1637 lines
48 KiB
C
1637 lines
48 KiB
C
/* Interprocedural constant propagation
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Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
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Free Software Foundation, Inc.
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Contributed by Razya Ladelsky <RAZYA@il.ibm.com>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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/* Interprocedural constant propagation. The aim of interprocedural constant
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propagation (IPCP) is to find which function's argument has the same
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constant value in each invocation throughout the whole program. For example,
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consider the following program:
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int g (int y)
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{
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printf ("value is %d",y);
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}
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int f (int x)
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{
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g (x);
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}
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int h (int y)
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{
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g (y);
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}
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void main (void)
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{
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f (3);
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h (3);
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}
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The IPCP algorithm will find that g's formal argument y is always called
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with the value 3.
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The algorithm used is based on "Interprocedural Constant Propagation", by
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David Callahan, Keith D Cooper, Ken Kennedy, Linda Torczon, Comp86, pg
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152-161
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The optimization is divided into three stages:
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First stage - intraprocedural analysis
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=======================================
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This phase computes jump_function and modification flags.
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A jump function for a callsite represents the values passed as an actual
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arguments of a given callsite. There are three types of values:
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Pass through - the caller's formal parameter is passed as an actual argument.
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Constant - a constant is passed as an actual argument.
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Unknown - neither of the above.
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The jump function info, ipa_jump_func, is stored in ipa_edge_args
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structure (defined in ipa_prop.h and pointed to by cgraph_node->aux)
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modified_flags are defined in ipa_node_params structure
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(defined in ipa_prop.h and pointed to by cgraph_edge->aux).
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-ipcp_generate_summary() is the first stage driver.
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Second stage - interprocedural analysis
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========================================
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This phase does the interprocedural constant propagation.
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It computes lattices for all formal parameters in the program
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and their value that may be:
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TOP - unknown.
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BOTTOM - non constant.
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CONSTANT - constant value.
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Lattice describing a formal parameter p will have a constant value if all
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callsites invoking this function have the same constant value passed to p.
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The lattices are stored in ipcp_lattice which is itself in ipa_node_params
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structure (defined in ipa_prop.h and pointed to by cgraph_edge->aux).
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-ipcp_iterate_stage() is the second stage driver.
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Third phase - transformation of function code
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============================================
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Propagates the constant-valued formals into the function.
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For each function whose parameters are constants, we create its clone.
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Then we process the clone in two ways:
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1. We insert an assignment statement 'parameter = const' at the beginning
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of the cloned function.
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2. For read-only parameters that do not live in memory, we replace all their
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uses with the constant.
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We also need to modify some callsites to call the cloned functions instead
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of the original ones. For a callsite passing an argument found to be a
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constant by IPCP, there are two different cases to handle:
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1. A constant is passed as an argument. In this case the callsite in the
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should be redirected to call the cloned callee.
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2. A parameter (of the caller) passed as an argument (pass through
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argument). In such cases both the caller and the callee have clones and
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only the callsite in the cloned caller is redirected to call to the
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cloned callee.
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This update is done in two steps: First all cloned functions are created
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during a traversal of the call graph, during which all callsites are
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redirected to call the cloned function. Then the callsites are traversed
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and many calls redirected back to fit the description above.
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-ipcp_insert_stage() is the third phase driver.
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This pass also performs devirtualization - turns virtual calls into direct
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ones if it can prove that all invocations of the function call the same
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callee. This is achieved by building a list of all base types (actually,
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their BINFOs) that individual parameters can have in an iterative matter
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just like propagating scalar constants and then examining whether virtual
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calls which take a parameter as their object fold to the same target for all
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these types. If we cannot enumerate all types or there is a type which does
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not have any BINFO associated with it, cannot_devirtualize of the associated
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parameter descriptor is set which is an equivalent of BOTTOM lattice value
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in standard IPA constant propagation.
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*/
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tree.h"
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#include "target.h"
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#include "gimple.h"
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#include "cgraph.h"
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#include "ipa-prop.h"
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#include "tree-flow.h"
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#include "tree-pass.h"
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#include "flags.h"
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#include "timevar.h"
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#include "diagnostic.h"
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#include "tree-pretty-print.h"
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#include "tree-dump.h"
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#include "tree-inline.h"
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#include "fibheap.h"
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#include "params.h"
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#include "ipa-inline.h"
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/* Number of functions identified as candidates for cloning. When not cloning
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we can simplify iterate stage not forcing it to go through the decision
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on what is profitable and what not. */
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static int n_cloning_candidates;
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/* Maximal count found in program. */
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static gcov_type max_count;
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/* Cgraph nodes that has been completely replaced by cloning during iterate
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* stage and will be removed after ipcp is finished. */
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static bitmap dead_nodes;
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static void ipcp_print_profile_data (FILE *);
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static void ipcp_function_scale_print (FILE *);
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/* Get the original node field of ipa_node_params associated with node NODE. */
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static inline struct cgraph_node *
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ipcp_get_orig_node (struct cgraph_node *node)
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{
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return IPA_NODE_REF (node)->ipcp_orig_node;
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}
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/* Return true if NODE describes a cloned/versioned function. */
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static inline bool
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ipcp_node_is_clone (struct cgraph_node *node)
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{
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return (ipcp_get_orig_node (node) != NULL);
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}
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/* Create ipa_node_params and its data structures for NEW_NODE. Set ORIG_NODE
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as the ipcp_orig_node field in ipa_node_params. */
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static void
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ipcp_init_cloned_node (struct cgraph_node *orig_node,
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struct cgraph_node *new_node)
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{
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gcc_checking_assert (ipa_node_params_vector
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&& (VEC_length (ipa_node_params_t,
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ipa_node_params_vector)
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> (unsigned) cgraph_max_uid));
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gcc_checking_assert (IPA_NODE_REF (new_node)->params);
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IPA_NODE_REF (new_node)->ipcp_orig_node = orig_node;
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}
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/* Return scale for NODE. */
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static inline gcov_type
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ipcp_get_node_scale (struct cgraph_node *node)
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{
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return IPA_NODE_REF (node)->count_scale;
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}
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/* Set COUNT as scale for NODE. */
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static inline void
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ipcp_set_node_scale (struct cgraph_node *node, gcov_type count)
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{
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IPA_NODE_REF (node)->count_scale = count;
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}
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/* Return whether LAT is a constant lattice. */
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static inline bool
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ipcp_lat_is_const (struct ipcp_lattice *lat)
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{
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if (lat->type == IPA_CONST_VALUE)
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return true;
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else
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return false;
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}
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/* Return whether LAT is a constant lattice that ipa-cp can actually insert
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into the code (i.e. constants excluding member pointers and pointers). */
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static inline bool
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ipcp_lat_is_insertable (struct ipcp_lattice *lat)
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{
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return lat->type == IPA_CONST_VALUE;
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}
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/* Return true if LAT1 and LAT2 are equal. */
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static inline bool
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ipcp_lats_are_equal (struct ipcp_lattice *lat1, struct ipcp_lattice *lat2)
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{
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gcc_assert (ipcp_lat_is_const (lat1) && ipcp_lat_is_const (lat2));
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if (lat1->type != lat2->type)
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return false;
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if (TREE_CODE (lat1->constant) == ADDR_EXPR
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&& TREE_CODE (lat2->constant) == ADDR_EXPR
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&& TREE_CODE (TREE_OPERAND (lat1->constant, 0)) == CONST_DECL
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&& TREE_CODE (TREE_OPERAND (lat2->constant, 0)) == CONST_DECL)
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return operand_equal_p (DECL_INITIAL (TREE_OPERAND (lat1->constant, 0)),
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DECL_INITIAL (TREE_OPERAND (lat2->constant, 0)), 0);
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else
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return operand_equal_p (lat1->constant, lat2->constant, 0);
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}
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/* Compute Meet arithmetics:
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Meet (IPA_BOTTOM, x) = IPA_BOTTOM
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Meet (IPA_TOP,x) = x
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Meet (const_a,const_b) = IPA_BOTTOM, if const_a != const_b.
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MEET (const_a,const_b) = const_a, if const_a == const_b.*/
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static void
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ipa_lattice_meet (struct ipcp_lattice *res, struct ipcp_lattice *lat1,
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struct ipcp_lattice *lat2)
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{
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if (lat1->type == IPA_BOTTOM || lat2->type == IPA_BOTTOM)
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{
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res->type = IPA_BOTTOM;
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return;
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}
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if (lat1->type == IPA_TOP)
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{
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res->type = lat2->type;
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res->constant = lat2->constant;
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return;
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}
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if (lat2->type == IPA_TOP)
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{
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res->type = lat1->type;
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res->constant = lat1->constant;
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return;
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}
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if (!ipcp_lats_are_equal (lat1, lat2))
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{
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res->type = IPA_BOTTOM;
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return;
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}
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res->type = lat1->type;
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res->constant = lat1->constant;
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}
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/* Return the lattice corresponding to the Ith formal parameter of the function
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described by INFO. */
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static inline struct ipcp_lattice *
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ipcp_get_lattice (struct ipa_node_params *info, int i)
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{
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return &(info->params[i].ipcp_lattice);
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}
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/* Given the jump function JFUNC, compute the lattice LAT that describes the
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value coming down the callsite. INFO describes the caller node so that
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pass-through jump functions can be evaluated. */
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static void
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ipcp_lattice_from_jfunc (struct ipa_node_params *info, struct ipcp_lattice *lat,
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struct ipa_jump_func *jfunc)
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{
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if (jfunc->type == IPA_JF_CONST)
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{
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lat->type = IPA_CONST_VALUE;
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lat->constant = jfunc->value.constant;
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}
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else if (jfunc->type == IPA_JF_PASS_THROUGH)
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{
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struct ipcp_lattice *caller_lat;
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tree cst;
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caller_lat = ipcp_get_lattice (info, jfunc->value.pass_through.formal_id);
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lat->type = caller_lat->type;
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if (caller_lat->type != IPA_CONST_VALUE)
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return;
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cst = caller_lat->constant;
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if (jfunc->value.pass_through.operation != NOP_EXPR)
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{
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tree restype;
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if (TREE_CODE_CLASS (jfunc->value.pass_through.operation)
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== tcc_comparison)
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restype = boolean_type_node;
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else
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restype = TREE_TYPE (cst);
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cst = fold_binary (jfunc->value.pass_through.operation,
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restype, cst, jfunc->value.pass_through.operand);
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}
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if (!cst || !is_gimple_ip_invariant (cst))
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lat->type = IPA_BOTTOM;
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lat->constant = cst;
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}
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else if (jfunc->type == IPA_JF_ANCESTOR)
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{
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struct ipcp_lattice *caller_lat;
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tree t;
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caller_lat = ipcp_get_lattice (info, jfunc->value.ancestor.formal_id);
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lat->type = caller_lat->type;
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if (caller_lat->type != IPA_CONST_VALUE)
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return;
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if (TREE_CODE (caller_lat->constant) != ADDR_EXPR)
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{
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/* This can happen when the constant is a NULL pointer. */
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lat->type = IPA_BOTTOM;
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return;
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}
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t = TREE_OPERAND (caller_lat->constant, 0);
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t = build_ref_for_offset (EXPR_LOCATION (t), t,
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jfunc->value.ancestor.offset,
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jfunc->value.ancestor.type, NULL, false);
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lat->constant = build_fold_addr_expr (t);
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}
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else
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lat->type = IPA_BOTTOM;
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}
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/* True when OLD_LAT and NEW_LAT values are not the same. */
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static bool
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ipcp_lattice_changed (struct ipcp_lattice *old_lat,
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struct ipcp_lattice *new_lat)
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{
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if (old_lat->type == new_lat->type)
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{
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if (!ipcp_lat_is_const (old_lat))
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return false;
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if (ipcp_lats_are_equal (old_lat, new_lat))
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return false;
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}
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return true;
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}
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/* Print all ipcp_lattices of all functions to F. */
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static void
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ipcp_print_all_lattices (FILE * f)
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{
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struct cgraph_node *node;
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int i, count;
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fprintf (f, "\nLattice:\n");
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for (node = cgraph_nodes; node; node = node->next)
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{
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struct ipa_node_params *info;
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if (!node->analyzed)
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continue;
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info = IPA_NODE_REF (node);
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fprintf (f, " Node: %s:\n", cgraph_node_name (node));
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count = ipa_get_param_count (info);
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for (i = 0; i < count; i++)
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{
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struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
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fprintf (f, " param [%d]: ", i);
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if (lat->type == IPA_CONST_VALUE)
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{
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tree cst = lat->constant;
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fprintf (f, "type is CONST ");
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print_generic_expr (f, cst, 0);
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if (TREE_CODE (cst) == ADDR_EXPR
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&& TREE_CODE (TREE_OPERAND (cst, 0)) == CONST_DECL)
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{
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fprintf (f, " -> ");
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print_generic_expr (f, DECL_INITIAL (TREE_OPERAND (cst, 0)),
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0);
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}
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}
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else if (lat->type == IPA_TOP)
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fprintf (f, "type is TOP");
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else
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fprintf (f, "type is BOTTOM");
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if (ipa_param_cannot_devirtualize_p (info, i))
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fprintf (f, " - cannot_devirtualize set\n");
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else if (ipa_param_types_vec_empty (info, i))
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fprintf (f, " - type list empty\n");
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else
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fprintf (f, "\n");
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}
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}
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}
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/* Return true if ipcp algorithms would allow cloning NODE. */
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static bool
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ipcp_versionable_function_p (struct cgraph_node *node)
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{
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struct cgraph_edge *edge;
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/* There are a number of generic reasons functions cannot be versioned. We
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also cannot remove parameters if there are type attributes such as fnspec
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present. */
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if (!node->local.versionable
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|| TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
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return false;
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/* Removing arguments doesn't work if the function takes varargs
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or use __builtin_apply_args. */
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for (edge = node->callees; edge; edge = edge->next_callee)
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{
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tree t = edge->callee->decl;
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if (DECL_BUILT_IN_CLASS (t) == BUILT_IN_NORMAL
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&& (DECL_FUNCTION_CODE (t) == BUILT_IN_APPLY_ARGS
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|| DECL_FUNCTION_CODE (t) == BUILT_IN_VA_START))
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return false;
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}
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return true;
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}
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/* Return true if this NODE is viable candidate for cloning. */
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static bool
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ipcp_cloning_candidate_p (struct cgraph_node *node)
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{
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int n_calls = 0;
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int n_hot_calls = 0;
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gcov_type direct_call_sum = 0;
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struct cgraph_edge *e;
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/* We never clone functions that are not visible from outside.
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FIXME: in future we should clone such functions when they are called with
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different constants, but current ipcp implementation is not good on this.
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*/
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if (cgraph_only_called_directly_p (node) || !node->analyzed)
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return false;
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/* When function address is taken, we are pretty sure it will be called in hidden way. */
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if (node->address_taken)
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{
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if (dump_file)
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fprintf (dump_file, "Not considering %s for cloning; address is taken.\n",
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cgraph_node_name (node));
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return false;
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}
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if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
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{
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if (dump_file)
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fprintf (dump_file, "Not considering %s for cloning; body is overwritable.\n",
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cgraph_node_name (node));
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return false;
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}
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if (!ipcp_versionable_function_p (node))
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{
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if (dump_file)
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fprintf (dump_file, "Not considering %s for cloning; body is not versionable.\n",
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cgraph_node_name (node));
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return false;
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}
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for (e = node->callers; e; e = e->next_caller)
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{
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direct_call_sum += e->count;
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n_calls ++;
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if (cgraph_maybe_hot_edge_p (e))
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n_hot_calls ++;
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}
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if (!n_calls)
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{
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if (dump_file)
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fprintf (dump_file, "Not considering %s for cloning; no direct calls.\n",
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cgraph_node_name (node));
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return false;
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}
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if (inline_summary (node)->self_size < n_calls)
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{
|
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if (dump_file)
|
|
fprintf (dump_file, "Considering %s for cloning; code would shrink.\n",
|
|
cgraph_node_name (node));
|
|
return true;
|
|
}
|
|
|
|
if (!flag_ipa_cp_clone)
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Not considering %s for cloning; -fipa-cp-clone disabled.\n",
|
|
cgraph_node_name (node));
|
|
return false;
|
|
}
|
|
|
|
if (!optimize_function_for_speed_p (DECL_STRUCT_FUNCTION (node->decl)))
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Not considering %s for cloning; optimizing it for size.\n",
|
|
cgraph_node_name (node));
|
|
return false;
|
|
}
|
|
|
|
/* When profile is available and function is hot, propagate into it even if
|
|
calls seems cold; constant propagation can improve function's speed
|
|
significantly. */
|
|
if (max_count)
|
|
{
|
|
if (direct_call_sum > node->count * 90 / 100)
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Considering %s for cloning; usually called directly.\n",
|
|
cgraph_node_name (node));
|
|
return true;
|
|
}
|
|
}
|
|
if (!n_hot_calls)
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Not considering %s for cloning; no hot calls.\n",
|
|
cgraph_node_name (node));
|
|
return false;
|
|
}
|
|
if (dump_file)
|
|
fprintf (dump_file, "Considering %s for cloning.\n",
|
|
cgraph_node_name (node));
|
|
return true;
|
|
}
|
|
|
|
/* Mark parameter with index I of function described by INFO as unsuitable for
|
|
devirtualization. Return true if it has already been marked so. */
|
|
|
|
static bool
|
|
ipa_set_param_cannot_devirtualize (struct ipa_node_params *info, int i)
|
|
{
|
|
bool ret = info->params[i].cannot_devirtualize;
|
|
info->params[i].cannot_devirtualize = true;
|
|
if (info->params[i].types)
|
|
VEC_free (tree, heap, info->params[i].types);
|
|
return ret;
|
|
}
|
|
|
|
/* Initialize ipcp_lattices array. The lattices corresponding to supported
|
|
types (integers, real types and Fortran constants defined as const_decls)
|
|
are initialized to IPA_TOP, the rest of them to IPA_BOTTOM. */
|
|
static void
|
|
ipcp_initialize_node_lattices (struct cgraph_node *node)
|
|
{
|
|
int i;
|
|
struct ipa_node_params *info = IPA_NODE_REF (node);
|
|
enum ipa_lattice_type type;
|
|
|
|
if (ipa_is_called_with_var_arguments (info))
|
|
type = IPA_BOTTOM;
|
|
else if (node->local.local)
|
|
type = IPA_TOP;
|
|
/* When cloning is allowed, we can assume that externally visible functions
|
|
are not called. We will compensate this by cloning later. */
|
|
else if (ipcp_cloning_candidate_p (node))
|
|
type = IPA_TOP, n_cloning_candidates ++;
|
|
else
|
|
type = IPA_BOTTOM;
|
|
|
|
for (i = 0; i < ipa_get_param_count (info) ; i++)
|
|
{
|
|
ipcp_get_lattice (info, i)->type = type;
|
|
if (type == IPA_BOTTOM)
|
|
ipa_set_param_cannot_devirtualize (info, i);
|
|
}
|
|
}
|
|
|
|
/* Build a constant tree with type TREE_TYPE and value according to LAT.
|
|
Return the tree, or, if it is not possible to convert such value
|
|
to TREE_TYPE, NULL. */
|
|
static tree
|
|
build_const_val (struct ipcp_lattice *lat, tree tree_type)
|
|
{
|
|
tree val;
|
|
|
|
gcc_assert (ipcp_lat_is_const (lat));
|
|
val = lat->constant;
|
|
|
|
if (!useless_type_conversion_p (tree_type, TREE_TYPE (val)))
|
|
{
|
|
if (fold_convertible_p (tree_type, val))
|
|
return fold_build1 (NOP_EXPR, tree_type, val);
|
|
else if (TYPE_SIZE (tree_type) == TYPE_SIZE (TREE_TYPE (val)))
|
|
return fold_build1 (VIEW_CONVERT_EXPR, tree_type, val);
|
|
else
|
|
return NULL;
|
|
}
|
|
return val;
|
|
}
|
|
|
|
/* Compute the proper scale for NODE. It is the ratio between the number of
|
|
direct calls (represented on the incoming cgraph_edges) and sum of all
|
|
invocations of NODE (represented as count in cgraph_node).
|
|
|
|
FIXME: This code is wrong. Since the callers can be also clones and
|
|
the clones are not scaled yet, the sums gets unrealistically high.
|
|
To properly compute the counts, we would need to do propagation across
|
|
callgraph (as external call to A might imply call to non-cloned B
|
|
if A's clone calls cloned B). */
|
|
static void
|
|
ipcp_compute_node_scale (struct cgraph_node *node)
|
|
{
|
|
gcov_type sum;
|
|
struct cgraph_edge *cs;
|
|
|
|
sum = 0;
|
|
/* Compute sum of all counts of callers. */
|
|
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
|
|
sum += cs->count;
|
|
/* Work around the unrealistically high sum problem. We just don't want
|
|
the non-cloned body to have negative or very low frequency. Since
|
|
majority of execution time will be spent in clones anyway, this should
|
|
give good enough profile. */
|
|
if (sum > node->count * 9 / 10)
|
|
sum = node->count * 9 / 10;
|
|
if (node->count == 0)
|
|
ipcp_set_node_scale (node, 0);
|
|
else
|
|
ipcp_set_node_scale (node, sum * REG_BR_PROB_BASE / node->count);
|
|
}
|
|
|
|
/* Return true if there are some formal parameters whose value is IPA_TOP (in
|
|
the whole compilation unit). Change their values to IPA_BOTTOM, since they
|
|
most probably get their values from outside of this compilation unit. */
|
|
static bool
|
|
ipcp_change_tops_to_bottom (void)
|
|
{
|
|
int i, count;
|
|
struct cgraph_node *node;
|
|
bool prop_again;
|
|
|
|
prop_again = false;
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
struct ipa_node_params *info = IPA_NODE_REF (node);
|
|
count = ipa_get_param_count (info);
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
if (lat->type == IPA_TOP)
|
|
{
|
|
prop_again = true;
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, "Forcing param ");
|
|
print_generic_expr (dump_file, ipa_get_param (info, i), 0);
|
|
fprintf (dump_file, " of node %s to bottom.\n",
|
|
cgraph_node_name (node));
|
|
}
|
|
lat->type = IPA_BOTTOM;
|
|
}
|
|
if (!ipa_param_cannot_devirtualize_p (info, i)
|
|
&& ipa_param_types_vec_empty (info, i))
|
|
{
|
|
prop_again = true;
|
|
ipa_set_param_cannot_devirtualize (info, i);
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, "Marking param ");
|
|
print_generic_expr (dump_file, ipa_get_param (info, i), 0);
|
|
fprintf (dump_file, " of node %s as unusable for "
|
|
"devirtualization.\n",
|
|
cgraph_node_name (node));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return prop_again;
|
|
}
|
|
|
|
/* Insert BINFO to the list of known types of parameter number I of the
|
|
function described by CALLEE_INFO. Return true iff the type information
|
|
associated with the callee parameter changed in any way. */
|
|
|
|
static bool
|
|
ipcp_add_param_type (struct ipa_node_params *callee_info, int i, tree binfo)
|
|
{
|
|
int j, count;
|
|
|
|
if (ipa_param_cannot_devirtualize_p (callee_info, i))
|
|
return false;
|
|
|
|
if (callee_info->params[i].types)
|
|
{
|
|
count = VEC_length (tree, callee_info->params[i].types);
|
|
for (j = 0; j < count; j++)
|
|
if (VEC_index (tree, callee_info->params[i].types, j) == binfo)
|
|
return false;
|
|
}
|
|
|
|
if (VEC_length (tree, callee_info->params[i].types)
|
|
== (unsigned) PARAM_VALUE (PARAM_DEVIRT_TYPE_LIST_SIZE))
|
|
return !ipa_set_param_cannot_devirtualize (callee_info, i);
|
|
|
|
VEC_safe_push (tree, heap, callee_info->params[i].types, binfo);
|
|
return true;
|
|
}
|
|
|
|
/* Copy known types information for parameter number CALLEE_IDX of CALLEE_INFO
|
|
from a parameter of CALLER_INFO as described by JF. Return true iff the
|
|
type information changed in any way. JF must be a pass-through or an
|
|
ancestor jump function. */
|
|
|
|
static bool
|
|
ipcp_copy_types (struct ipa_node_params *caller_info,
|
|
struct ipa_node_params *callee_info,
|
|
int callee_idx, struct ipa_jump_func *jf)
|
|
{
|
|
int caller_idx, j, count;
|
|
bool res;
|
|
|
|
if (ipa_param_cannot_devirtualize_p (callee_info, callee_idx))
|
|
return false;
|
|
|
|
if (jf->type == IPA_JF_PASS_THROUGH)
|
|
{
|
|
if (jf->value.pass_through.operation != NOP_EXPR)
|
|
{
|
|
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
|
|
return true;
|
|
}
|
|
caller_idx = jf->value.pass_through.formal_id;
|
|
}
|
|
else
|
|
caller_idx = jf->value.ancestor.formal_id;
|
|
|
|
if (ipa_param_cannot_devirtualize_p (caller_info, caller_idx))
|
|
{
|
|
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
|
|
return true;
|
|
}
|
|
|
|
if (!caller_info->params[caller_idx].types)
|
|
return false;
|
|
|
|
res = false;
|
|
count = VEC_length (tree, caller_info->params[caller_idx].types);
|
|
for (j = 0; j < count; j++)
|
|
{
|
|
tree binfo = VEC_index (tree, caller_info->params[caller_idx].types, j);
|
|
if (jf->type == IPA_JF_ANCESTOR)
|
|
{
|
|
binfo = get_binfo_at_offset (binfo, jf->value.ancestor.offset,
|
|
jf->value.ancestor.type);
|
|
if (!binfo)
|
|
{
|
|
ipa_set_param_cannot_devirtualize (callee_info, callee_idx);
|
|
return true;
|
|
}
|
|
}
|
|
res |= ipcp_add_param_type (callee_info, callee_idx, binfo);
|
|
}
|
|
return res;
|
|
}
|
|
|
|
/* Propagate type information for parameter of CALLEE_INFO number I as
|
|
described by JF. CALLER_INFO describes the caller. Return true iff the
|
|
type information changed in any way. */
|
|
|
|
static bool
|
|
ipcp_propagate_types (struct ipa_node_params *caller_info,
|
|
struct ipa_node_params *callee_info,
|
|
struct ipa_jump_func *jf, int i)
|
|
{
|
|
switch (jf->type)
|
|
{
|
|
case IPA_JF_UNKNOWN:
|
|
case IPA_JF_CONST_MEMBER_PTR:
|
|
case IPA_JF_CONST:
|
|
break;
|
|
|
|
case IPA_JF_KNOWN_TYPE:
|
|
return ipcp_add_param_type (callee_info, i, jf->value.base_binfo);
|
|
|
|
case IPA_JF_PASS_THROUGH:
|
|
case IPA_JF_ANCESTOR:
|
|
return ipcp_copy_types (caller_info, callee_info, i, jf);
|
|
}
|
|
|
|
/* If we reach this we cannot use this parameter for devirtualization. */
|
|
return !ipa_set_param_cannot_devirtualize (callee_info, i);
|
|
}
|
|
|
|
/* Interprocedural analysis. The algorithm propagates constants from the
|
|
caller's parameters to the callee's arguments. */
|
|
static void
|
|
ipcp_propagate_stage (void)
|
|
{
|
|
int i;
|
|
struct ipcp_lattice inc_lat = { IPA_BOTTOM, NULL };
|
|
struct ipcp_lattice new_lat = { IPA_BOTTOM, NULL };
|
|
struct ipcp_lattice *dest_lat;
|
|
struct cgraph_edge *cs;
|
|
struct ipa_jump_func *jump_func;
|
|
struct ipa_func_list *wl;
|
|
int count;
|
|
|
|
ipa_check_create_node_params ();
|
|
ipa_check_create_edge_args ();
|
|
|
|
/* Initialize worklist to contain all functions. */
|
|
wl = ipa_init_func_list ();
|
|
while (wl)
|
|
{
|
|
struct cgraph_node *node = ipa_pop_func_from_list (&wl);
|
|
struct ipa_node_params *info = IPA_NODE_REF (node);
|
|
|
|
for (cs = node->callees; cs; cs = cs->next_callee)
|
|
{
|
|
struct ipa_node_params *callee_info = IPA_NODE_REF (cs->callee);
|
|
struct ipa_edge_args *args = IPA_EDGE_REF (cs);
|
|
|
|
if (ipa_is_called_with_var_arguments (callee_info)
|
|
|| !cs->callee->analyzed
|
|
|| ipa_is_called_with_var_arguments (callee_info))
|
|
continue;
|
|
|
|
count = ipa_get_cs_argument_count (args);
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
jump_func = ipa_get_ith_jump_func (args, i);
|
|
ipcp_lattice_from_jfunc (info, &inc_lat, jump_func);
|
|
dest_lat = ipcp_get_lattice (callee_info, i);
|
|
ipa_lattice_meet (&new_lat, &inc_lat, dest_lat);
|
|
if (ipcp_lattice_changed (&new_lat, dest_lat))
|
|
{
|
|
dest_lat->type = new_lat.type;
|
|
dest_lat->constant = new_lat.constant;
|
|
ipa_push_func_to_list (&wl, cs->callee);
|
|
}
|
|
|
|
if (ipcp_propagate_types (info, callee_info, jump_func, i))
|
|
ipa_push_func_to_list (&wl, cs->callee);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Call the constant propagation algorithm and re-call it if necessary
|
|
(if there are undetermined values left). */
|
|
static void
|
|
ipcp_iterate_stage (void)
|
|
{
|
|
struct cgraph_node *node;
|
|
n_cloning_candidates = 0;
|
|
|
|
if (dump_file)
|
|
fprintf (dump_file, "\nIPA iterate stage:\n\n");
|
|
|
|
if (in_lto_p)
|
|
ipa_update_after_lto_read ();
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
ipcp_initialize_node_lattices (node);
|
|
ipcp_compute_node_scale (node);
|
|
}
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
ipcp_print_all_lattices (dump_file);
|
|
ipcp_function_scale_print (dump_file);
|
|
}
|
|
|
|
ipcp_propagate_stage ();
|
|
if (ipcp_change_tops_to_bottom ())
|
|
/* Some lattices have changed from IPA_TOP to IPA_BOTTOM.
|
|
This change should be propagated. */
|
|
{
|
|
gcc_assert (n_cloning_candidates);
|
|
ipcp_propagate_stage ();
|
|
}
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, "\nIPA lattices after propagation:\n");
|
|
ipcp_print_all_lattices (dump_file);
|
|
if (dump_flags & TDF_DETAILS)
|
|
ipcp_print_profile_data (dump_file);
|
|
}
|
|
}
|
|
|
|
/* Check conditions to forbid constant insertion to function described by
|
|
NODE. */
|
|
static inline bool
|
|
ipcp_node_modifiable_p (struct cgraph_node *node)
|
|
{
|
|
/* Once we will be able to do in-place replacement, we can be more
|
|
lax here. */
|
|
return ipcp_versionable_function_p (node);
|
|
}
|
|
|
|
/* Print count scale data structures. */
|
|
static void
|
|
ipcp_function_scale_print (FILE * f)
|
|
{
|
|
struct cgraph_node *node;
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
if (!node->analyzed)
|
|
continue;
|
|
fprintf (f, "printing scale for %s: ", cgraph_node_name (node));
|
|
fprintf (f, "value is " HOST_WIDE_INT_PRINT_DEC
|
|
" \n", (HOST_WIDE_INT) ipcp_get_node_scale (node));
|
|
}
|
|
}
|
|
|
|
/* Print counts of all cgraph nodes. */
|
|
static void
|
|
ipcp_print_func_profile_counts (FILE * f)
|
|
{
|
|
struct cgraph_node *node;
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
fprintf (f, "function %s: ", cgraph_node_name (node));
|
|
fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC
|
|
" \n", (HOST_WIDE_INT) node->count);
|
|
}
|
|
}
|
|
|
|
/* Print counts of all cgraph edges. */
|
|
static void
|
|
ipcp_print_call_profile_counts (FILE * f)
|
|
{
|
|
struct cgraph_node *node;
|
|
struct cgraph_edge *cs;
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
for (cs = node->callees; cs; cs = cs->next_callee)
|
|
{
|
|
fprintf (f, "%s -> %s ", cgraph_node_name (cs->caller),
|
|
cgraph_node_name (cs->callee));
|
|
fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC " \n",
|
|
(HOST_WIDE_INT) cs->count);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Print profile info for all functions. */
|
|
static void
|
|
ipcp_print_profile_data (FILE * f)
|
|
{
|
|
fprintf (f, "\nNODE COUNTS :\n");
|
|
ipcp_print_func_profile_counts (f);
|
|
fprintf (f, "\nCS COUNTS stage:\n");
|
|
ipcp_print_call_profile_counts (f);
|
|
}
|
|
|
|
/* Build and initialize ipa_replace_map struct according to LAT. This struct is
|
|
processed by versioning, which operates according to the flags set.
|
|
PARM_TREE is the formal parameter found to be constant. LAT represents the
|
|
constant. */
|
|
static struct ipa_replace_map *
|
|
ipcp_create_replace_map (tree parm_tree, struct ipcp_lattice *lat)
|
|
{
|
|
struct ipa_replace_map *replace_map;
|
|
tree const_val;
|
|
|
|
const_val = build_const_val (lat, TREE_TYPE (parm_tree));
|
|
if (const_val == NULL_TREE)
|
|
{
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, " const ");
|
|
print_generic_expr (dump_file, lat->constant, 0);
|
|
fprintf (dump_file, " can't be converted to param ");
|
|
print_generic_expr (dump_file, parm_tree, 0);
|
|
fprintf (dump_file, "\n");
|
|
}
|
|
return NULL;
|
|
}
|
|
replace_map = ggc_alloc_ipa_replace_map ();
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, " replacing param ");
|
|
print_generic_expr (dump_file, parm_tree, 0);
|
|
fprintf (dump_file, " with const ");
|
|
print_generic_expr (dump_file, const_val, 0);
|
|
fprintf (dump_file, "\n");
|
|
}
|
|
replace_map->old_tree = parm_tree;
|
|
replace_map->new_tree = const_val;
|
|
replace_map->replace_p = true;
|
|
replace_map->ref_p = false;
|
|
|
|
return replace_map;
|
|
}
|
|
|
|
/* Return true if this callsite should be redirected to the original callee
|
|
(instead of the cloned one). */
|
|
static bool
|
|
ipcp_need_redirect_p (struct cgraph_edge *cs)
|
|
{
|
|
struct ipa_node_params *orig_callee_info;
|
|
int i, count;
|
|
struct cgraph_node *node = cs->callee, *orig;
|
|
|
|
if (!n_cloning_candidates)
|
|
return false;
|
|
|
|
if ((orig = ipcp_get_orig_node (node)) != NULL)
|
|
node = orig;
|
|
if (ipcp_get_orig_node (cs->caller))
|
|
return false;
|
|
|
|
orig_callee_info = IPA_NODE_REF (node);
|
|
count = ipa_get_param_count (orig_callee_info);
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (orig_callee_info, i);
|
|
struct ipa_jump_func *jump_func;
|
|
|
|
jump_func = ipa_get_ith_jump_func (IPA_EDGE_REF (cs), i);
|
|
if ((ipcp_lat_is_const (lat)
|
|
&& jump_func->type != IPA_JF_CONST)
|
|
|| (!ipa_param_cannot_devirtualize_p (orig_callee_info, i)
|
|
&& !ipa_param_types_vec_empty (orig_callee_info, i)
|
|
&& jump_func->type != IPA_JF_CONST
|
|
&& jump_func->type != IPA_JF_KNOWN_TYPE))
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Fix the callsites and the call graph after function cloning was done. */
|
|
static void
|
|
ipcp_update_callgraph (void)
|
|
{
|
|
struct cgraph_node *node;
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
if (node->analyzed && ipcp_node_is_clone (node))
|
|
{
|
|
bitmap args_to_skip = NULL;
|
|
struct cgraph_node *orig_node = ipcp_get_orig_node (node);
|
|
struct ipa_node_params *info = IPA_NODE_REF (orig_node);
|
|
int i, count = ipa_get_param_count (info);
|
|
struct cgraph_edge *cs, *next;
|
|
|
|
if (node->local.can_change_signature)
|
|
{
|
|
args_to_skip = BITMAP_ALLOC (NULL);
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
|
|
/* We can proactively remove obviously unused arguments. */
|
|
if (!ipa_is_param_used (info, i))
|
|
{
|
|
bitmap_set_bit (args_to_skip, i);
|
|
continue;
|
|
}
|
|
|
|
if (lat->type == IPA_CONST_VALUE)
|
|
bitmap_set_bit (args_to_skip, i);
|
|
}
|
|
}
|
|
for (cs = node->callers; cs; cs = next)
|
|
{
|
|
next = cs->next_caller;
|
|
if (!ipcp_node_is_clone (cs->caller) && ipcp_need_redirect_p (cs))
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Redirecting edge %s/%i -> %s/%i "
|
|
"back to %s/%i.",
|
|
cgraph_node_name (cs->caller), cs->caller->uid,
|
|
cgraph_node_name (cs->callee), cs->callee->uid,
|
|
cgraph_node_name (orig_node), orig_node->uid);
|
|
cgraph_redirect_edge_callee (cs, orig_node);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Update profiling info for versioned functions and the functions they were
|
|
versioned from. */
|
|
static void
|
|
ipcp_update_profiling (void)
|
|
{
|
|
struct cgraph_node *node, *orig_node;
|
|
gcov_type scale, scale_complement;
|
|
struct cgraph_edge *cs;
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
if (ipcp_node_is_clone (node))
|
|
{
|
|
orig_node = ipcp_get_orig_node (node);
|
|
scale = ipcp_get_node_scale (orig_node);
|
|
node->count = orig_node->count * scale / REG_BR_PROB_BASE;
|
|
scale_complement = REG_BR_PROB_BASE - scale;
|
|
|
|
/* Negative scale complement can result from insane profile data
|
|
in which the total incoming edge counts in this module is
|
|
larger than the callee's entry count. The insane profile data
|
|
usually gets generated due to the following reasons:
|
|
|
|
1) in multithreaded programs, when profile data is dumped
|
|
to gcda files in gcov_exit, some other threads are still running.
|
|
The profile counters are dumped in bottom up order (call graph).
|
|
The caller's BB counters may still be updated while the callee's
|
|
counter data is already saved to disk.
|
|
|
|
2) Comdat functions: comdat functions' profile data are not
|
|
allocated in comdat. When a comdat callee function gets inlined
|
|
at some callsites after instrumentation, and the remaining calls
|
|
to this function resolves to a comdat copy in another module,
|
|
the profile counters for this function are split. This can
|
|
result in sum of incoming edge counts from this module being
|
|
larger than callee instance's entry count. */
|
|
|
|
if (scale_complement < 0 && flag_profile_correction)
|
|
scale_complement = 0;
|
|
|
|
orig_node->count =
|
|
orig_node->count * scale_complement / REG_BR_PROB_BASE;
|
|
for (cs = node->callees; cs; cs = cs->next_callee)
|
|
cs->count = cs->count * scale / REG_BR_PROB_BASE;
|
|
for (cs = orig_node->callees; cs; cs = cs->next_callee)
|
|
cs->count = cs->count * scale_complement / REG_BR_PROB_BASE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* If NODE was cloned, how much would program grow? */
|
|
static long
|
|
ipcp_estimate_growth (struct cgraph_node *node)
|
|
{
|
|
struct cgraph_edge *cs;
|
|
int redirectable_node_callers = 0;
|
|
int removable_args = 0;
|
|
bool need_original
|
|
= !cgraph_will_be_removed_from_program_if_no_direct_calls (node);
|
|
struct ipa_node_params *info;
|
|
int i, count;
|
|
int growth;
|
|
|
|
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
|
|
if (cs->caller == node || !ipcp_need_redirect_p (cs))
|
|
redirectable_node_callers++;
|
|
else
|
|
need_original = true;
|
|
|
|
/* If we will be able to fully replace original node, we never increase
|
|
program size. */
|
|
if (!need_original)
|
|
return 0;
|
|
|
|
info = IPA_NODE_REF (node);
|
|
count = ipa_get_param_count (info);
|
|
if (node->local.can_change_signature)
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
|
|
/* We can proactively remove obviously unused arguments. */
|
|
if (!ipa_is_param_used (info, i))
|
|
removable_args++;
|
|
|
|
if (lat->type == IPA_CONST_VALUE)
|
|
removable_args++;
|
|
}
|
|
|
|
/* We make just very simple estimate of savings for removal of operand from
|
|
call site. Precise cost is difficult to get, as our size metric counts
|
|
constants and moves as free. Generally we are looking for cases that
|
|
small function is called very many times. */
|
|
growth = inline_summary (node)->self_size
|
|
- removable_args * redirectable_node_callers;
|
|
if (growth < 0)
|
|
return 0;
|
|
return growth;
|
|
}
|
|
|
|
|
|
/* Estimate cost of cloning NODE. */
|
|
static long
|
|
ipcp_estimate_cloning_cost (struct cgraph_node *node)
|
|
{
|
|
int freq_sum = 1;
|
|
gcov_type count_sum = 1;
|
|
struct cgraph_edge *e;
|
|
int cost;
|
|
|
|
cost = ipcp_estimate_growth (node) * 1000;
|
|
if (!cost)
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Versioning of %s will save code size\n",
|
|
cgraph_node_name (node));
|
|
return 0;
|
|
}
|
|
|
|
for (e = node->callers; e; e = e->next_caller)
|
|
if (!bitmap_bit_p (dead_nodes, e->caller->uid)
|
|
&& !ipcp_need_redirect_p (e))
|
|
{
|
|
count_sum += e->count;
|
|
freq_sum += e->frequency + 1;
|
|
}
|
|
|
|
if (max_count)
|
|
cost /= count_sum * 1000 / max_count + 1;
|
|
else
|
|
cost /= freq_sum * 1000 / REG_BR_PROB_BASE + 1;
|
|
if (dump_file)
|
|
fprintf (dump_file, "Cost of versioning %s is %i, (size: %i, freq: %i)\n",
|
|
cgraph_node_name (node), cost, inline_summary (node)->self_size,
|
|
freq_sum);
|
|
return cost + 1;
|
|
}
|
|
|
|
/* Walk indirect calls of NODE and if any polymorphic can be turned into a
|
|
direct one now, do so. */
|
|
|
|
static void
|
|
ipcp_process_devirtualization_opportunities (struct cgraph_node *node)
|
|
{
|
|
struct ipa_node_params *info = IPA_NODE_REF (node);
|
|
struct cgraph_edge *ie, *next_ie;
|
|
|
|
for (ie = node->indirect_calls; ie; ie = next_ie)
|
|
{
|
|
int param_index, types_count, j;
|
|
HOST_WIDE_INT token;
|
|
tree target, delta;
|
|
|
|
next_ie = ie->next_callee;
|
|
if (!ie->indirect_info->polymorphic)
|
|
continue;
|
|
param_index = ie->indirect_info->param_index;
|
|
if (param_index == -1
|
|
|| ipa_param_cannot_devirtualize_p (info, param_index)
|
|
|| ipa_param_types_vec_empty (info, param_index))
|
|
continue;
|
|
|
|
token = ie->indirect_info->otr_token;
|
|
target = NULL_TREE;
|
|
types_count = VEC_length (tree, info->params[param_index].types);
|
|
for (j = 0; j < types_count; j++)
|
|
{
|
|
tree binfo = VEC_index (tree, info->params[param_index].types, j);
|
|
tree d;
|
|
tree t = gimple_get_virt_mehtod_for_binfo (token, binfo, &d, true);
|
|
|
|
if (!t)
|
|
{
|
|
target = NULL_TREE;
|
|
break;
|
|
}
|
|
else if (!target)
|
|
{
|
|
target = t;
|
|
delta = d;
|
|
}
|
|
else if (target != t || !tree_int_cst_equal (delta, d))
|
|
{
|
|
target = NULL_TREE;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (target)
|
|
ipa_make_edge_direct_to_target (ie, target, delta);
|
|
}
|
|
}
|
|
|
|
/* Return number of live constant parameters. */
|
|
static int
|
|
ipcp_const_param_count (struct cgraph_node *node)
|
|
{
|
|
int const_param = 0;
|
|
struct ipa_node_params *info = IPA_NODE_REF (node);
|
|
int count = ipa_get_param_count (info);
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
if ((ipcp_lat_is_insertable (lat)
|
|
/* Do not count obviously unused arguments. */
|
|
&& ipa_is_param_used (info, i))
|
|
|| (!ipa_param_cannot_devirtualize_p (info, i)
|
|
&& !ipa_param_types_vec_empty (info, i)))
|
|
const_param++;
|
|
}
|
|
return const_param;
|
|
}
|
|
|
|
/* Given that a formal parameter of NODE given by INDEX is known to be constant
|
|
CST, try to find any indirect edges that can be made direct and make them
|
|
so. Note that INDEX is the number the parameter at the time of analyzing
|
|
parameter uses and parameter removals should not be considered for it. (In
|
|
fact, the parameter itself has just been removed.) */
|
|
|
|
static void
|
|
ipcp_discover_new_direct_edges (struct cgraph_node *node, int index, tree cst)
|
|
{
|
|
struct cgraph_edge *ie, *next_ie;
|
|
|
|
for (ie = node->indirect_calls; ie; ie = next_ie)
|
|
{
|
|
struct cgraph_indirect_call_info *ici = ie->indirect_info;
|
|
|
|
next_ie = ie->next_callee;
|
|
if (ici->param_index != index
|
|
|| ici->polymorphic)
|
|
continue;
|
|
|
|
ipa_make_edge_direct_to_target (ie, cst, NULL_TREE);
|
|
}
|
|
}
|
|
|
|
|
|
/* Propagate the constant parameters found by ipcp_iterate_stage()
|
|
to the function's code. */
|
|
static void
|
|
ipcp_insert_stage (void)
|
|
{
|
|
struct cgraph_node *node, *node1 = NULL;
|
|
int i;
|
|
VEC (cgraph_edge_p, heap) * redirect_callers;
|
|
VEC (ipa_replace_map_p,gc)* replace_trees;
|
|
int node_callers, count;
|
|
tree parm_tree;
|
|
struct ipa_replace_map *replace_param;
|
|
fibheap_t heap;
|
|
long overall_size = 0, new_size = 0;
|
|
long max_new_size;
|
|
|
|
ipa_check_create_node_params ();
|
|
ipa_check_create_edge_args ();
|
|
if (dump_file)
|
|
fprintf (dump_file, "\nIPA insert stage:\n\n");
|
|
|
|
dead_nodes = BITMAP_ALLOC (NULL);
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
if (node->analyzed)
|
|
{
|
|
if (node->count > max_count)
|
|
max_count = node->count;
|
|
overall_size += inline_summary (node)->self_size;
|
|
}
|
|
|
|
max_new_size = overall_size;
|
|
if (max_new_size < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
|
|
max_new_size = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
|
|
max_new_size = max_new_size * PARAM_VALUE (PARAM_IPCP_UNIT_GROWTH) / 100 + 1;
|
|
|
|
/* First collect all functions we proved to have constant arguments to
|
|
heap. */
|
|
heap = fibheap_new ();
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
{
|
|
struct ipa_node_params *info;
|
|
/* Propagation of the constant is forbidden in certain conditions. */
|
|
if (!node->analyzed || !ipcp_node_modifiable_p (node))
|
|
continue;
|
|
info = IPA_NODE_REF (node);
|
|
if (ipa_is_called_with_var_arguments (info))
|
|
continue;
|
|
if (ipcp_const_param_count (node))
|
|
node->aux = fibheap_insert (heap, ipcp_estimate_cloning_cost (node),
|
|
node);
|
|
}
|
|
|
|
/* Now clone in priority order until code size growth limits are met or
|
|
heap is emptied. */
|
|
while (!fibheap_empty (heap))
|
|
{
|
|
struct ipa_node_params *info;
|
|
int growth = 0;
|
|
bitmap args_to_skip;
|
|
struct cgraph_edge *cs;
|
|
|
|
node = (struct cgraph_node *)fibheap_extract_min (heap);
|
|
node->aux = NULL;
|
|
if (dump_file)
|
|
fprintf (dump_file, "considering function %s\n",
|
|
cgraph_node_name (node));
|
|
|
|
growth = ipcp_estimate_growth (node);
|
|
|
|
if (new_size + growth > max_new_size)
|
|
break;
|
|
if (growth
|
|
&& optimize_function_for_size_p (DECL_STRUCT_FUNCTION (node->decl)))
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Not versioning, cold code would grow");
|
|
continue;
|
|
}
|
|
|
|
info = IPA_NODE_REF (node);
|
|
count = ipa_get_param_count (info);
|
|
|
|
replace_trees = VEC_alloc (ipa_replace_map_p, gc, 1);
|
|
|
|
if (node->local.can_change_signature)
|
|
args_to_skip = BITMAP_GGC_ALLOC ();
|
|
else
|
|
args_to_skip = NULL;
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
parm_tree = ipa_get_param (info, i);
|
|
|
|
/* We can proactively remove obviously unused arguments. */
|
|
if (!ipa_is_param_used (info, i))
|
|
{
|
|
if (args_to_skip)
|
|
bitmap_set_bit (args_to_skip, i);
|
|
continue;
|
|
}
|
|
|
|
if (lat->type == IPA_CONST_VALUE)
|
|
{
|
|
replace_param =
|
|
ipcp_create_replace_map (parm_tree, lat);
|
|
if (replace_param == NULL)
|
|
break;
|
|
VEC_safe_push (ipa_replace_map_p, gc, replace_trees, replace_param);
|
|
if (args_to_skip)
|
|
bitmap_set_bit (args_to_skip, i);
|
|
}
|
|
}
|
|
if (i < count)
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "Not versioning, some parameters couldn't be replaced");
|
|
continue;
|
|
}
|
|
|
|
new_size += growth;
|
|
|
|
/* Look if original function becomes dead after cloning. */
|
|
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
|
|
if (cs->caller == node || ipcp_need_redirect_p (cs))
|
|
break;
|
|
if (!cs && cgraph_will_be_removed_from_program_if_no_direct_calls (node))
|
|
bitmap_set_bit (dead_nodes, node->uid);
|
|
|
|
/* Compute how many callers node has. */
|
|
node_callers = 0;
|
|
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
|
|
node_callers++;
|
|
redirect_callers = VEC_alloc (cgraph_edge_p, heap, node_callers);
|
|
for (cs = node->callers; cs != NULL; cs = cs->next_caller)
|
|
if (!cs->indirect_inlining_edge)
|
|
VEC_quick_push (cgraph_edge_p, redirect_callers, cs);
|
|
|
|
/* Redirecting all the callers of the node to the
|
|
new versioned node. */
|
|
node1 =
|
|
cgraph_create_virtual_clone (node, redirect_callers, replace_trees,
|
|
args_to_skip, "constprop");
|
|
args_to_skip = NULL;
|
|
VEC_free (cgraph_edge_p, heap, redirect_callers);
|
|
replace_trees = NULL;
|
|
|
|
if (node1 == NULL)
|
|
continue;
|
|
ipcp_process_devirtualization_opportunities (node1);
|
|
|
|
if (dump_file)
|
|
fprintf (dump_file, "versioned function %s with growth %i, overall %i\n",
|
|
cgraph_node_name (node), (int)growth, (int)new_size);
|
|
ipcp_init_cloned_node (node, node1);
|
|
|
|
info = IPA_NODE_REF (node);
|
|
for (i = 0; i < count; i++)
|
|
{
|
|
struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
|
|
if (lat->type == IPA_CONST_VALUE)
|
|
ipcp_discover_new_direct_edges (node1, i, lat->constant);
|
|
}
|
|
|
|
if (dump_file)
|
|
dump_function_to_file (node1->decl, dump_file, dump_flags);
|
|
|
|
for (cs = node->callees; cs; cs = cs->next_callee)
|
|
if (cs->callee->aux)
|
|
{
|
|
fibheap_delete_node (heap, (fibnode_t) cs->callee->aux);
|
|
cs->callee->aux = fibheap_insert (heap,
|
|
ipcp_estimate_cloning_cost (cs->callee),
|
|
cs->callee);
|
|
}
|
|
}
|
|
|
|
while (!fibheap_empty (heap))
|
|
{
|
|
if (dump_file)
|
|
fprintf (dump_file, "skipping function %s\n",
|
|
cgraph_node_name (node));
|
|
node = (struct cgraph_node *) fibheap_extract_min (heap);
|
|
node->aux = NULL;
|
|
}
|
|
fibheap_delete (heap);
|
|
BITMAP_FREE (dead_nodes);
|
|
ipcp_update_callgraph ();
|
|
ipcp_update_profiling ();
|
|
}
|
|
|
|
/* The IPCP driver. */
|
|
static unsigned int
|
|
ipcp_driver (void)
|
|
{
|
|
cgraph_remove_unreachable_nodes (true,dump_file);
|
|
if (dump_file)
|
|
{
|
|
fprintf (dump_file, "\nIPA structures before propagation:\n");
|
|
if (dump_flags & TDF_DETAILS)
|
|
ipa_print_all_params (dump_file);
|
|
ipa_print_all_jump_functions (dump_file);
|
|
}
|
|
ipa_check_create_node_params ();
|
|
ipa_check_create_edge_args ();
|
|
/* 2. Do the interprocedural propagation. */
|
|
ipcp_iterate_stage ();
|
|
/* 3. Insert the constants found to the functions. */
|
|
ipcp_insert_stage ();
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "\nProfiling info after insert stage:\n");
|
|
ipcp_print_profile_data (dump_file);
|
|
}
|
|
/* Free all IPCP structures. */
|
|
ipa_free_all_structures_after_ipa_cp ();
|
|
if (dump_file)
|
|
fprintf (dump_file, "\nIPA constant propagation end\n");
|
|
return 0;
|
|
}
|
|
|
|
/* Initialization and computation of IPCP data structures. This is the initial
|
|
intraprocedural analysis of functions, which gathers information to be
|
|
propagated later on. */
|
|
|
|
static void
|
|
ipcp_generate_summary (void)
|
|
{
|
|
struct cgraph_node *node;
|
|
|
|
if (dump_file)
|
|
fprintf (dump_file, "\nIPA constant propagation start:\n");
|
|
ipa_register_cgraph_hooks ();
|
|
|
|
for (node = cgraph_nodes; node; node = node->next)
|
|
if (node->analyzed)
|
|
{
|
|
/* Unreachable nodes should have been eliminated before ipcp. */
|
|
gcc_assert (node->needed || node->reachable);
|
|
|
|
node->local.versionable = tree_versionable_function_p (node->decl);
|
|
ipa_analyze_node (node);
|
|
}
|
|
}
|
|
|
|
/* Write ipcp summary for nodes in SET. */
|
|
static void
|
|
ipcp_write_summary (cgraph_node_set set,
|
|
varpool_node_set vset ATTRIBUTE_UNUSED)
|
|
{
|
|
ipa_prop_write_jump_functions (set);
|
|
}
|
|
|
|
/* Read ipcp summary. */
|
|
static void
|
|
ipcp_read_summary (void)
|
|
{
|
|
ipa_prop_read_jump_functions ();
|
|
}
|
|
|
|
/* Gate for IPCP optimization. */
|
|
static bool
|
|
cgraph_gate_cp (void)
|
|
{
|
|
/* FIXME: We should remove the optimize check after we ensure we never run
|
|
IPA passes when not optimizing. */
|
|
return flag_ipa_cp && optimize;
|
|
}
|
|
|
|
struct ipa_opt_pass_d pass_ipa_cp =
|
|
{
|
|
{
|
|
IPA_PASS,
|
|
"cp", /* name */
|
|
cgraph_gate_cp, /* gate */
|
|
ipcp_driver, /* execute */
|
|
NULL, /* sub */
|
|
NULL, /* next */
|
|
0, /* static_pass_number */
|
|
TV_IPA_CONSTANT_PROP, /* tv_id */
|
|
0, /* properties_required */
|
|
0, /* properties_provided */
|
|
0, /* properties_destroyed */
|
|
0, /* todo_flags_start */
|
|
TODO_dump_cgraph | TODO_dump_func |
|
|
TODO_remove_functions | TODO_ggc_collect /* todo_flags_finish */
|
|
},
|
|
ipcp_generate_summary, /* generate_summary */
|
|
ipcp_write_summary, /* write_summary */
|
|
ipcp_read_summary, /* read_summary */
|
|
NULL, /* write_optimization_summary */
|
|
NULL, /* read_optimization_summary */
|
|
NULL, /* stmt_fixup */
|
|
0, /* TODOs */
|
|
NULL, /* function_transform */
|
|
NULL, /* variable_transform */
|
|
};
|