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jit: use deep unsharing of trees [PR 95314]

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PR jit/95314 reports a internal error inside verify_gimple, which
turned out to be due to reusing the result of
gcc_jit_lvalue_get_address in several functions, leading to tree nodes
shared between multiple function bodies.

This patch fixes the issue by adopting the "Deep unsharing" strategy
described in the comment in gimplify.c preceding mostly_copy_tree_r:
to mark all of the jit "frontend"'s expression tree nodes with
TREE_VISITED, and to set LANG_HOOKS_DEEP_UNSHARING, so that "they are
unshared on the first reference within functions when the regular
unsharing algorithm runs".

gcc/jit/ChangeLog:
	PR jit/95314
	* dummy-frontend.c (LANG_HOOKS_DEEP_UNSHARING): Define to be true.
	* jit-playback.h (gcc::jit::playback::rvalue): Mark tree node with
	TREE_VISITED.

gcc/testsuite/ChangeLog:
	PR jit/95314
	* jit.dg/all-non-failing-tests.h: Add test-pr95314-rvalue-reuse.c.
	* jit.dg/test-pr95314-rvalue-reuse.c: New test.
This commit is contained in:
David Malcolm 2020-05-27 09:44:07 -04:00
parent ac43b32ce2
commit c98bd673ef
4 changed files with 75 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
gcc/jit/dummy-frontend.c
View File

@ -269,6 +269,9 @@ jit_langhook_getdecls (void)
#undef LANG_HOOKS_GETDECLS
#define LANG_HOOKS_GETDECLS jit_langhook_getdecls
#undef LANG_HOOKS_DEEP_UNSHARING
#define LANG_HOOKS_DEEP_UNSHARING true
struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
#include "gt-jit-dummy-frontend.h"

7
gcc/jit/jit-playback.h
View File

@ -576,7 +576,12 @@ public:
rvalue (context *ctxt, tree inner)
: m_ctxt (ctxt),
m_inner (inner)
{}
{
/* Pre-mark tree nodes with TREE_VISITED so that they can be
deeply unshared during gimplification (including across
functions); this requires LANG_HOOKS_DEEP_UNSHARING to be true. */
TREE_VISITED (inner) = 1;
}
rvalue *
as_rvalue () { return this; }

10
gcc/testsuite/jit.dg/all-non-failing-tests.h
View File

@ -234,6 +234,13 @@
#undef create_code
#undef verify_code
/* test-pr95314-rvalue-reuse.c. */
#define create_code create_code_pr95314_rvalue_reuse
#define verify_code verify_code_pr95314_rvalue_reuse
#include "test-pr95314-rvalue-reuse.c"
#undef create_code
#undef verify_code
/* test-reading-struct.c */
#define create_code create_code_reading_struct
#define verify_code verify_code_reading_struct
@ -401,6 +408,9 @@ const struct testcase testcases[] = {
{"pr95306_builtin_types",
create_code_pr95306_builtin_types,
verify_code_pr95306_builtin_types},
{"pr95314_rvalue_reuse",
create_code_pr95314_rvalue_reuse,
verify_code_pr95314_rvalue_reuse},
{"reading_struct ",
create_code_reading_struct ,
verify_code_reading_struct },

56
gcc/testsuite/jit.dg/test-pr95314-rvalue-reuse.c Normal file
View File

@ -0,0 +1,56 @@
#include <libgccjit.h>
#include "harness.h"
void create_code (gcc_jit_context *ctxt, void *user_data)
{
gcc_jit_type *t_int = gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
gcc_jit_type *t_void = gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID);
gcc_jit_type *t_const_char_ptr
= gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CONST_CHAR_PTR);
gcc_jit_lvalue *global
= gcc_jit_context_new_global (ctxt, NULL, GCC_JIT_GLOBAL_INTERNAL,
t_const_char_ptr, "pr95314_global");
gcc_jit_rvalue *global_ref = gcc_jit_lvalue_get_address(global, NULL);
gcc_jit_param *param_string
= gcc_jit_context_new_param (ctxt, NULL, t_const_char_ptr, "string");
gcc_jit_function *puts_func
= gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_IMPORTED,
t_int, "puts", 1, &param_string, 0);
#define NUM_INNER_FNS 3
gcc_jit_function *inner_fns[NUM_INNER_FNS];
for (int i = 0; i < NUM_INNER_FNS; i++)
{
char fnname[128];
sprintf (fnname, "pr95314_inner_%i", i);
inner_fns[i]
= gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_INTERNAL,
t_void, fnname, 0, NULL, 0);
gcc_jit_block *block = gcc_jit_function_new_block (inner_fns[i], NULL);
gcc_jit_rvalue *arg
= gcc_jit_context_new_cast (ctxt, NULL, global_ref, t_const_char_ptr);
gcc_jit_block_add_eval (block, NULL,
gcc_jit_context_new_call (ctxt, NULL, puts_func,
1, &arg));
gcc_jit_block_end_with_void_return (block, NULL);
}
gcc_jit_function *outer_func
= gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_EXPORTED,
t_void, "pr95314_outer", 0, NULL, 0);
gcc_jit_block *block = gcc_jit_function_new_block (outer_func, NULL);
for (int i = 0; i < NUM_INNER_FNS; i++)
gcc_jit_block_add_eval (block, NULL,
gcc_jit_context_new_call (ctxt, NULL, inner_fns[i],
0, NULL));
gcc_jit_block_end_with_void_return (block, NULL);
}
void
verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
{
CHECK_NON_NULL (result);
(void)gcc_jit_result_get_code (result, "pr95314_outer");
}