> On Jul 28, 2022, at 3:28 AM, Richard Biener <rguent...@suse.de> wrote: > > On Tue, 19 Jul 2022, Qing Zhao wrote: > >> From a09f39ded462611286a44d9e8273de8342673ba2 Mon Sep 17 00:00:00 2001 >> From: Qing Zhao <qing.z...@oracle.com> >> Date: Mon, 18 Jul 2022 18:12:26 +0000 >> Subject: [PATCH 2/2] Use new flag DECL_NOT_FLEXARRAY in __builtin_object_size >> [PR101836] >> >> Use new flag DECL_NOT_FLEXARRAY to determine whether the trailing array >> of a structure is flexible array member in __builtin_object_size. >> >> gcc/ChangeLog: >> >> PR tree-optimization/101836 >> * tree-object-size.cc (addr_object_size): Use array_at_struct_end_p >> and DECL_NOT_FLEXARRAY to determine a flexible array member reference. >> >> gcc/testsuite/ChangeLog: >> >> PR tree-optimization/101836 >> * gcc.dg/pr101836.c: New test. >> * gcc.dg/pr101836_1.c: New test. >> * gcc.dg/pr101836_2.c: New test. >> * gcc.dg/pr101836_3.c: New test. >> * gcc.dg/pr101836_4.c: New test. >> * gcc.dg/pr101836_5.c: New test. >> * gcc.dg/strict-flex-array-2.c: New test. >> * gcc.dg/strict-flex-array-3.c: New test. >> --- >> gcc/testsuite/gcc.dg/pr101836.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/pr101836_1.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/pr101836_2.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/pr101836_3.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/pr101836_4.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/pr101836_5.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/strict-flex-array-2.c | 60 ++++++++++++++++++++++ >> gcc/testsuite/gcc.dg/strict-flex-array-3.c | 60 ++++++++++++++++++++++ >> gcc/tree-object-size.cc | 18 +++---- >> 9 files changed, 489 insertions(+), 9 deletions(-) >> create mode 100644 gcc/testsuite/gcc.dg/pr101836.c >> create mode 100644 gcc/testsuite/gcc.dg/pr101836_1.c >> create mode 100644 gcc/testsuite/gcc.dg/pr101836_2.c >> create mode 100644 gcc/testsuite/gcc.dg/pr101836_3.c >> create mode 100644 gcc/testsuite/gcc.dg/pr101836_4.c >> create mode 100644 gcc/testsuite/gcc.dg/pr101836_5.c >> create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-2.c >> create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-3.c >> >> diff --git a/gcc/testsuite/gcc.dg/pr101836.c >> b/gcc/testsuite/gcc.dg/pr101836.c >> new file mode 100644 >> index 00000000000..e5b4e5160a4 >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836.c >> @@ -0,0 +1,60 @@ >> +/* -fstrict-flex-array is aliased with -ftrict-flex-array=3, which is the >> + strictest, only [] is treated as flexible array. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), 16); >> + expect(__builtin_object_size(trailing_1->c, 1), 4); >> + expect(__builtin_object_size(trailing_0->c, 1), 0); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/pr101836_1.c >> b/gcc/testsuite/gcc.dg/pr101836_1.c >> new file mode 100644 >> index 00000000000..30ea20427a5 >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836_1.c >> @@ -0,0 +1,60 @@ >> +/* -fstrict-flex-array=3 is the strictest, only [] is treated as >> + flexible array. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=3" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), 16); >> + expect(__builtin_object_size(trailing_1->c, 1), 4); >> + expect(__builtin_object_size(trailing_0->c, 1), 0); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/pr101836_2.c >> b/gcc/testsuite/gcc.dg/pr101836_2.c >> new file mode 100644 >> index 00000000000..ebbe88f433c >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836_2.c >> @@ -0,0 +1,60 @@ >> +/* When -fstrict-flex-array=2, only [] and [0] are treated as flexiable >> + arrays. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=2" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), 16); >> + expect(__builtin_object_size(trailing_1->c, 1), 4); >> + expect(__builtin_object_size(trailing_0->c, 1), -1); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/pr101836_3.c >> b/gcc/testsuite/gcc.dg/pr101836_3.c >> new file mode 100644 >> index 00000000000..d4ba0afe5bc >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836_3.c >> @@ -0,0 +1,60 @@ >> +/* When -fstrict-flex-array=1, [], [0], and [1] are treated as flexible >> + arrays. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=1" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), 16); >> + expect(__builtin_object_size(trailing_1->c, 1), -1); >> + expect(__builtin_object_size(trailing_0->c, 1), -1); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/pr101836_4.c >> b/gcc/testsuite/gcc.dg/pr101836_4.c >> new file mode 100644 >> index 00000000000..b10d3ce312d >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836_4.c >> @@ -0,0 +1,60 @@ >> +/* when -fstrict-flex-array=0, all trailing arrays are treated as >> + flexible arrays. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=0" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), -1); >> + expect(__builtin_object_size(trailing_1->c, 1), -1); >> + expect(__builtin_object_size(trailing_0->c, 1), -1); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/pr101836_5.c >> b/gcc/testsuite/gcc.dg/pr101836_5.c >> new file mode 100644 >> index 00000000000..2f6b5f7ae1f >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr101836_5.c >> @@ -0,0 +1,60 @@ >> +/* -fno-strict-flex-array is aliased to -fstrict-flex-array=0, >> + all trailing arrays are treated as flexible array. */ >> +/* PR tree-optimization/101836 */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fno-strict-flex-array" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4]; >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1]; >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0]; >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), -1); >> + expect(__builtin_object_size(trailing_1->c, 1), -1); >> + expect(__builtin_object_size(trailing_0->c, 1), -1); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-2.c >> b/gcc/testsuite/gcc.dg/strict-flex-array-2.c >> new file mode 100644 >> index 00000000000..326ddcfeda5 >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/strict-flex-array-2.c >> @@ -0,0 +1,60 @@ >> +/* test the combination of attribute strict_flex_array and option >> + -fstrict-flex-array: when both attribute and option specified, >> + attribute will have higher priority. */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=3" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4] __attribute__ ((strict_flex_array (0))); >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1] __attribute__ ((strict_flex_array (1))); >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0] __attribute__ ((strict_flex_array (2))); >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), -1); >> + expect(__builtin_object_size(trailing_1->c, 1), -1); >> + expect(__builtin_object_size(trailing_0->c, 1), -1); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-3.c >> b/gcc/testsuite/gcc.dg/strict-flex-array-3.c >> new file mode 100644 >> index 00000000000..990c5bb6223 >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/strict-flex-array-3.c >> @@ -0,0 +1,60 @@ >> +/* test the combination of attribute strict_flex_array and option >> + -fstrict-flex-array: when both attribute and option specified, >> + attribute will have higher priority. */ >> +/* { dg-do run } */ >> +/* { dg-options "-O2 -fstrict-flex-array=0" } */ >> + >> +#include <stdio.h> >> + >> +#define expect(p, _v) do { \ >> + size_t v = _v; \ >> + if (p == v) \ >> + printf("ok: %s == %zd\n", #p, p); \ >> + else \ >> + { \ >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ >> + __builtin_abort (); \ >> + } \ >> +} while (0); >> + >> +struct trailing_array_1 { >> + int a; >> + int b; >> + int c[4] __attribute__ ((strict_flex_array (1))); >> +}; >> + >> +struct trailing_array_2 { >> + int a; >> + int b; >> + int c[1] __attribute__ ((strict_flex_array (2))); >> +}; >> + >> +struct trailing_array_3 { >> + int a; >> + int b; >> + int c[0] __attribute__ ((strict_flex_array (3))); >> +}; >> +struct trailing_array_4 { >> + int a; >> + int b; >> + int c[]; >> +}; >> + >> +void __attribute__((__noinline__)) stuff( >> + struct trailing_array_1 *normal, >> + struct trailing_array_2 *trailing_1, >> + struct trailing_array_3 *trailing_0, >> + struct trailing_array_4 *trailing_flex) >> +{ >> + expect(__builtin_object_size(normal->c, 1), 16); >> + expect(__builtin_object_size(trailing_1->c, 1), 4); >> + expect(__builtin_object_size(trailing_0->c, 1), 0); >> + expect(__builtin_object_size(trailing_flex->c, 1), -1); >> +} >> + >> +int main(int argc, char *argv[]) >> +{ >> + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void >> *)argv[0]); >> + >> + return 0; >> +} >> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc >> index 4eb454a4a33..90710ecba72 100644 >> --- a/gcc/tree-object-size.cc >> +++ b/gcc/tree-object-size.cc >> @@ -604,9 +604,9 @@ addr_object_size (struct object_size_info *osi, >> const_tree ptr, >> else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) >> { >> tree v = var; >> - /* For &X->fld, compute object size only if fld isn't the last >> - field, as struct { int i; char c[1]; } is often used instead >> - of flexible array member. */ >> + bool is_flexible_array_mem_ref = false; >> + /* For &X->fld, compute object size if fld isn't a flexible array >> + member. */ >> while (v && v != pt_var) >> switch (TREE_CODE (v)) >> { >> @@ -633,6 +633,9 @@ addr_object_size (struct object_size_info *osi, >> const_tree ptr, >> v = NULL_TREE; >> break; >> } >> + is_flexible_array_mem_ref >> + = array_at_struct_end_p (v) >> + && !DECL_NOT_FLEXARRAY (TREE_OPERAND (v, 1)); > > As said in the review for the first patch array_at_struct_end_p should > check DECL_NOT_FLEXARRAY. Okay.
Then, should we change the name of “array_at_struct_end_p” to a more descriptive name, for example,”flexible_array_member_p”? Otherwise, It’s really confusing. > > OK with removing the extra check here. Okay. thanks. Qing > >> while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) >> if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) >> != UNION_TYPE >> @@ -645,12 +648,9 @@ addr_object_size (struct object_size_info *osi, >> const_tree ptr, >> && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) >> == RECORD_TYPE) >> { >> - tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); >> - for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) >> - if (TREE_CODE (fld_chain) == FIELD_DECL) >> - break; >> - >> - if (fld_chain) >> + /* compute object size only if v is not a >> + flexible array member. */ >> + if (!is_flexible_array_mem_ref) >> { >> v = NULL_TREE; >> break; >> > > -- > Richard Biener <rguent...@suse.de> > SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, > Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; > HRB 36809 (AG Nuernberg)