gcc/gcc/ubsan.c

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/* UndefinedBehaviorSanitizer, undefined behavior detector.
Copyright (C) 2013 Free Software Foundation, Inc.
Contributed by Marek Polacek <polacek@redhat.com>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "cgraph.h"
#include "gimple.h"
#include "hashtab.h"
#include "pointer-set.h"
#include "output.h"
#include "tm_p.h"
#include "toplev.h"
#include "ubsan.h"
#include "c-family/c-common.h"
/* Map from a tree to a VAR_DECL tree. */
struct GTY(()) tree_type_map {
struct tree_map_base type;
tree decl;
};
#define tree_type_map_eq tree_map_base_eq
#define tree_type_map_hash tree_map_base_hash
#define tree_type_map_marked_p tree_map_base_marked_p
static GTY ((if_marked ("tree_type_map_marked_p"), param_is (struct tree_type_map)))
htab_t decl_tree_for_type;
/* Lookup a VAR_DECL for TYPE, and return it if we find one. */
static tree
decl_for_type_lookup (tree type)
{
/* If the hash table is not initialized yet, create it now. */
if (decl_tree_for_type == NULL)
{
decl_tree_for_type = htab_create_ggc (10, tree_type_map_hash,
tree_type_map_eq, 0);
/* That also means we don't have to bother with the lookup. */
return NULL_TREE;
}
struct tree_type_map *h, in;
in.type.from = type;
h = (struct tree_type_map *)
htab_find_with_hash (decl_tree_for_type, &in, TYPE_UID (type));
return h ? h->decl : NULL_TREE;
}
/* Insert a mapping TYPE->DECL in the VAR_DECL for type hashtable. */
static void
decl_for_type_insert (tree type, tree decl)
{
struct tree_type_map *h;
void **slot;
h = ggc_alloc_tree_type_map ();
h->type.from = type;
h->decl = decl;
slot = htab_find_slot_with_hash (decl_tree_for_type, h, TYPE_UID (type),
INSERT);
*(struct tree_type_map **) slot = h;
}
/* Helper routine, which encodes a value in the pointer_sized_int_node.
Arguments with precision <= POINTER_SIZE are passed directly,
the rest is passed by reference. T is a value we are to encode. */
tree
ubsan_encode_value (tree t)
{
tree type = TREE_TYPE (t);
switch (TREE_CODE (type))
{
case INTEGER_TYPE:
if (TYPE_PRECISION (type) <= POINTER_SIZE)
return fold_build1 (NOP_EXPR, pointer_sized_int_node, t);
else
return build_fold_addr_expr (t);
case REAL_TYPE:
{
unsigned int bitsize = GET_MODE_BITSIZE (TYPE_MODE (type));
if (bitsize <= POINTER_SIZE)
{
tree itype = build_nonstandard_integer_type (bitsize, true);
t = fold_build1 (VIEW_CONVERT_EXPR, itype, t);
return fold_convert (pointer_sized_int_node, t);
}
else
{
if (!TREE_ADDRESSABLE (t))
{
/* The reason for this is that we don't want to pessimize
code by making vars unnecessarily addressable. */
tree var = create_tmp_var (TREE_TYPE (t), NULL);
tree tem = build2 (MODIFY_EXPR, void_type_node, var, t);
t = build_fold_addr_expr (var);
return build2 (COMPOUND_EXPR, TREE_TYPE (t), tem, t);
}
else
return build_fold_addr_expr (t);
}
}
default:
gcc_unreachable ();
}
}
/* Build
struct __ubsan_type_descriptor
{
unsigned short __typekind;
unsigned short __typeinfo;
char __typename[];
}
type. */
static tree
ubsan_type_descriptor_type (void)
{
static const char *field_names[3]
= { "__typekind", "__typeinfo", "__typename" };
tree fields[3], ret;
tree itype = build_range_type (sizetype, size_zero_node, NULL_TREE);
tree flex_arr_type = build_array_type (char_type_node, itype);
ret = make_node (RECORD_TYPE);
for (int i = 0; i < 3; i++)
{
fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL,
get_identifier (field_names[i]),
(i == 2) ? flex_arr_type
: short_unsigned_type_node);
DECL_CONTEXT (fields[i]) = ret;
if (i)
DECL_CHAIN (fields[i - 1]) = fields[i];
}
TYPE_FIELDS (ret) = fields[0];
TYPE_NAME (ret) = get_identifier ("__ubsan_type_descriptor");
layout_type (ret);
return ret;
}
/* Build
struct __ubsan_source_location
{
const char *__filename;
unsigned int __line;
unsigned int __column;
}
type. */
static tree
ubsan_source_location_type (void)
{
static const char *field_names[3]
= { "__filename", "__line", "__column" };
tree fields[3], ret;
tree const_char_type = build_qualified_type (char_type_node,
TYPE_QUAL_CONST);
ret = make_node (RECORD_TYPE);
for (int i = 0; i < 3; i++)
{
fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL,
get_identifier (field_names[i]),
(i == 0) ? build_pointer_type (const_char_type)
: unsigned_type_node);
DECL_CONTEXT (fields[i]) = ret;
if (i)
DECL_CHAIN (fields[i - 1]) = fields[i];
}
TYPE_FIELDS (ret) = fields[0];
TYPE_NAME (ret) = get_identifier ("__ubsan_source_location");
layout_type (ret);
return ret;
}
/* Helper routine that returns a CONSTRUCTOR of __ubsan_source_location
type with its fields filled from a location_t LOC. */
static tree
ubsan_source_location (location_t loc)
{
expanded_location xloc;
tree type = ubsan_source_location_type ();
xloc = expand_location (loc);
/* Fill in the values from LOC. */
size_t len = strlen (xloc.file);
tree str = build_string (len + 1, xloc.file);
TREE_TYPE (str) = build_array_type (char_type_node,
build_index_type (size_int (len)));
TREE_READONLY (str) = 1;
TREE_STATIC (str) = 1;
str = build_fold_addr_expr_loc (loc, str);
tree ctor = build_constructor_va (type, 3, NULL_TREE, str, NULL_TREE,
build_int_cst (unsigned_type_node,
xloc.line), NULL_TREE,
build_int_cst (unsigned_type_node,
xloc.column));
TREE_CONSTANT (ctor) = 1;
TREE_STATIC (ctor) = 1;
return ctor;
}
/* This routine returns a magic number for TYPE. */
static unsigned short
get_ubsan_type_info_for_type (tree type)
{
gcc_assert (TYPE_SIZE (type) && tree_fits_uhwi_p (TYPE_SIZE (type)));
decl.c, [...]: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/ada/ * gcc-interface/decl.c, gcc-interface/utils.c, gcc-interface/utils2.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/c-family/ * c-common.c, c-cppbuiltin.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/c/ * c-decl.c, c-typeck.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/cp/ * call.c, class.c, decl.c, error.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/objc/ * objc-encoding.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. gcc/ * alias.c, asan.c, builtins.c, cfgexpand.c, cgraph.c, config/aarch64/aarch64.c, config/alpha/predicates.md, config/arm/arm.c, config/darwin.c, config/epiphany/epiphany.c, config/i386/i386.c, config/iq2000/iq2000.c, config/m32c/m32c-pragma.c, config/mep/mep-pragma.c, config/mips/mips.c, config/picochip/picochip.c, config/rs6000/rs6000.c, cppbuiltin.c, dbxout.c, dwarf2out.c, emit-rtl.c, except.c, expr.c, fold-const.c, function.c, gimple-fold.c, godump.c, ipa-cp.c, ipa-prop.c, omp-low.c, predict.c, sdbout.c, stor-layout.c, trans-mem.c, tree-object-size.c, tree-sra.c, tree-ssa-ccp.c, tree-ssa-forwprop.c, tree-ssa-loop-ivcanon.c, tree-ssa-loop-ivopts.c, tree-ssa-loop-niter.c, tree-ssa-loop-prefetch.c, tree-ssa-strlen.c, tree-stdarg.c, tree-switch-conversion.c, tree-vect-generic.c, tree-vect-loop.c, tree-vect-patterns.c, tree-vrp.c, tree.c, tsan.c, ubsan.c, varasm.c: Replace tree_low_cst (..., 1) with tree_to_uhwi throughout. From-SVN: r204961
2013-11-18 15:52:19 +01:00
int prec = exact_log2 (tree_to_uhwi (TYPE_SIZE (type)));
gcc_assert (prec != -1);
return (prec << 1) | !TYPE_UNSIGNED (type);
}
/* Helper routine that returns ADDR_EXPR of a VAR_DECL of a type
descriptor. It first looks into the pointer map; if not found,
create the VAR_DECL, put it into the pointer map and return the
ADDR_EXPR of it. TYPE describes a particular type. */
tree
ubsan_type_descriptor (tree type)
{
/* See through any typedefs. */
type = TYPE_MAIN_VARIANT (type);
tree decl = decl_for_type_lookup (type);
if (decl != NULL_TREE)
return decl;
tree dtype = ubsan_type_descriptor_type ();
const char *tname;
unsigned short tkind, tinfo;
/* At least for INTEGER_TYPE/REAL_TYPE/COMPLEX_TYPE, this should work.
For e.g. type_unsigned_for (type) or bit-fields, the TYPE_NAME
would be NULL. */
if (TYPE_NAME (type) != NULL)
{
if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
tname = IDENTIFIER_POINTER (TYPE_NAME (type));
else
tname = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
}
else
tname = "<unknown>";
if (TREE_CODE (type) == INTEGER_TYPE)
{
/* For INTEGER_TYPE, this is 0x0000. */
tkind = 0x000;
tinfo = get_ubsan_type_info_for_type (type);
}
else if (TREE_CODE (type) == REAL_TYPE)
/* We don't have float support yet. */
gcc_unreachable ();
else
gcc_unreachable ();
/* Create a new VAR_DECL of type descriptor. */
char tmp_name[32];
static unsigned int type_var_id_num;
ASM_GENERATE_INTERNAL_LABEL (tmp_name, "Lubsan_type", type_var_id_num++);
decl = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier (tmp_name),
dtype);
TREE_STATIC (decl) = 1;
TREE_PUBLIC (decl) = 0;
DECL_ARTIFICIAL (decl) = 1;
DECL_IGNORED_P (decl) = 1;
DECL_EXTERNAL (decl) = 0;
size_t len = strlen (tname);
tree str = build_string (len + 1, tname);
TREE_TYPE (str) = build_array_type (char_type_node,
build_index_type (size_int (len)));
TREE_READONLY (str) = 1;
TREE_STATIC (str) = 1;
tree ctor = build_constructor_va (dtype, 3, NULL_TREE,
build_int_cst (short_unsigned_type_node,
tkind), NULL_TREE,
build_int_cst (short_unsigned_type_node,
tinfo), NULL_TREE, str);
TREE_CONSTANT (ctor) = 1;
TREE_STATIC (ctor) = 1;
DECL_INITIAL (decl) = ctor;
rest_of_decl_compilation (decl, 1, 0);
/* Save the address of the VAR_DECL into the pointer map. */
decl = build_fold_addr_expr (decl);
decl_for_type_insert (type, decl);
return decl;
}
/* Create a structure for the ubsan library. NAME is a name of the new
structure. The arguments in ... are of __ubsan_type_descriptor type
and there are at most two of them. */
tree
ubsan_create_data (const char *name, location_t loc, ...)
{
va_list args;
tree ret, t;
tree fields[3];
vec<tree, va_gc> *saved_args = NULL;
size_t i = 0;
/* Firstly, create a pointer to type descriptor type. */
tree td_type = ubsan_type_descriptor_type ();
TYPE_READONLY (td_type) = 1;
td_type = build_pointer_type (td_type);
/* Create the structure type. */
ret = make_node (RECORD_TYPE);
if (loc != UNKNOWN_LOCATION)
{
fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL, NULL_TREE,
ubsan_source_location_type ());
DECL_CONTEXT (fields[i]) = ret;
i++;
}
va_start (args, loc);
for (t = va_arg (args, tree); t != NULL_TREE;
i++, t = va_arg (args, tree))
{
gcc_checking_assert (i < 3);
/* Save the tree argument for later use. */
vec_safe_push (saved_args, t);
fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL, NULL_TREE,
td_type);
DECL_CONTEXT (fields[i]) = ret;
if (i)
DECL_CHAIN (fields[i - 1]) = fields[i];
}
TYPE_FIELDS (ret) = fields[0];
TYPE_NAME (ret) = get_identifier (name);
layout_type (ret);
va_end (args);
/* Now, fill in the type. */
char tmp_name[32];
static unsigned int ubsan_var_id_num;
ASM_GENERATE_INTERNAL_LABEL (tmp_name, "Lubsan_data", ubsan_var_id_num++);
tree var = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier (tmp_name),
ret);
TREE_STATIC (var) = 1;
TREE_PUBLIC (var) = 0;
DECL_ARTIFICIAL (var) = 1;
DECL_IGNORED_P (var) = 1;
DECL_EXTERNAL (var) = 0;
vec<constructor_elt, va_gc> *v;
vec_alloc (v, i);
tree ctor = build_constructor (ret, v);
/* If desirable, set the __ubsan_source_location element. */
if (loc != UNKNOWN_LOCATION)
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, ubsan_source_location (loc));
size_t nelts = vec_safe_length (saved_args);
for (i = 0; i < nelts; i++)
{
t = (*saved_args)[i];
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, t);
}
TREE_CONSTANT (ctor) = 1;
TREE_STATIC (ctor) = 1;
DECL_INITIAL (var) = ctor;
rest_of_decl_compilation (var, 1, 0);
return var;
}
/* Instrument the __builtin_unreachable call. We just call the libubsan
routine instead. */
tree
ubsan_instrument_unreachable (location_t loc)
{
tree data = ubsan_create_data ("__ubsan_unreachable_data", loc, NULL_TREE);
tree t = builtin_decl_explicit (BUILT_IN_UBSAN_HANDLE_BUILTIN_UNREACHABLE);
return build_call_expr_loc (loc, t, 1, build_fold_addr_expr_loc (loc, data));
}
/* Return true if T is a call to a libubsan routine. */
bool
is_ubsan_builtin_p (tree t)
{
gcc_checking_assert (TREE_CODE (t) == FUNCTION_DECL);
return strncmp (IDENTIFIER_POINTER (DECL_NAME (t)),
"__builtin___ubsan_", 18) == 0;
}
#include "gt-ubsan.h"