From f9555f402caf35c8b1065daaebc361b753f025a2 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 31 Jul 2008 10:02:49 +0200 Subject: [PATCH] re PR c/36970 (GCC should display a warning when trying to free a static array) PR c/36970 * builtins.c (maybe_emit_free_warning): New function. (expand_builtin): Process BUILT_IN_FREE even at -O0. Call maybe_emit_free_warning for BUILT_IN_FREE. * gcc.dg/free-1.c: New test. * gcc.dg/free-2.c: New test. From-SVN: r138362 --- gcc/ChangeLog | 5 +++++ gcc/builtins.c | 29 ++++++++++++++++++++++++++++- gcc/testsuite/ChangeLog | 4 ++++ gcc/testsuite/gcc.dg/free-1.c | 26 ++++++++++++++++++++++++++ gcc/testsuite/gcc.dg/free-2.c | 26 ++++++++++++++++++++++++++ 5 files changed, 89 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/free-1.c create mode 100644 gcc/testsuite/gcc.dg/free-2.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 49799a84695..7da323b6cae 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2008-07-31 Jakub Jelinek + PR c/36970 + * builtins.c (maybe_emit_free_warning): New function. + (expand_builtin): Process BUILT_IN_FREE even at -O0. Call + maybe_emit_free_warning for BUILT_IN_FREE. + PR debug/36278 * dwarf2out.c (get_context_die): New function. (force_decl_die, force_type_die): Use it. diff --git a/gcc/builtins.c b/gcc/builtins.c index ca551915c50..2dffd53e604 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -207,6 +207,7 @@ static rtx expand_builtin_memory_chk (tree, rtx, enum machine_mode, enum built_in_function); static void maybe_emit_chk_warning (tree, enum built_in_function); static void maybe_emit_sprintf_chk_warning (tree, enum built_in_function); +static void maybe_emit_free_warning (tree); static tree fold_builtin_object_size (tree, tree); static tree fold_builtin_strcat_chk (tree, tree, tree, tree); static tree fold_builtin_strncat_chk (tree, tree, tree, tree, tree); @@ -6130,7 +6131,8 @@ expand_builtin (tree exp, rtx target, rtx subtarget, enum machine_mode mode, if (!optimize && !called_as_built_in (fndecl) && DECL_ASSEMBLER_NAME_SET_P (fndecl) - && fcode != BUILT_IN_ALLOCA) + && fcode != BUILT_IN_ALLOCA + && fcode != BUILT_IN_FREE) return expand_call (exp, target, ignore); /* The built-in function expanders test for target == const0_rtx @@ -7007,6 +7009,10 @@ expand_builtin (tree exp, rtx target, rtx subtarget, enum machine_mode mode, maybe_emit_sprintf_chk_warning (exp, fcode); break; + case BUILT_IN_FREE: + maybe_emit_free_warning (exp); + break; + default: /* just do library call, if unknown builtin */ break; } @@ -11981,6 +11987,27 @@ maybe_emit_sprintf_chk_warning (tree exp, enum built_in_function fcode) } } +/* Emit warning if a free is called with address of a variable. */ + +static void +maybe_emit_free_warning (tree exp) +{ + tree arg = CALL_EXPR_ARG (exp, 0); + + STRIP_NOPS (arg); + if (TREE_CODE (arg) != ADDR_EXPR) + return; + + arg = get_base_address (TREE_OPERAND (arg, 0)); + if (arg == NULL || INDIRECT_REF_P (arg)) + return; + + if (SSA_VAR_P (arg)) + warning (0, "%Kattempt to free a non-heap object %qD", exp, arg); + else + warning (0, "%Kattempt to free a non-heap object", exp); +} + /* Fold a call to __builtin_object_size with arguments PTR and OST, if possible. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 0df56e856ee..c4257ea1566 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,9 @@ 2008-07-31 Jakub Jelinek + PR c/36970 + * gcc.dg/free-1.c: New test. + * gcc.dg/free-2.c: New test. + PR debug/36278 * g++.dg/debug/namespace2.C: New test. diff --git a/gcc/testsuite/gcc.dg/free-1.c b/gcc/testsuite/gcc.dg/free-1.c new file mode 100644 index 00000000000..5496c84fdb8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/free-1.c @@ -0,0 +1,26 @@ +/* PR c/36970 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +extern void free (void *); + +char *p, buf3[10], d; +struct S { char a; int b; } *r; + +void foo (void) +{ + char buf[10], buf2[10], c; + static char buf4[10], e; + char *q = buf; + free (p); + free (q); /* { dg-warning "attempt to free a non-heap object" } */ + free (buf2); /* { dg-warning "attempt to free a non-heap object" } */ + free (&c); /* { dg-warning "attempt to free a non-heap object" } */ + free (buf3); /* { dg-warning "attempt to free a non-heap object" } */ + free (&d); /* { dg-warning "attempt to free a non-heap object" } */ + free (buf4); /* { dg-warning "attempt to free a non-heap object" } */ + free (&e); /* { dg-warning "attempt to free a non-heap object" } */ + free (&r->a); + free ("abcd"); /* { dg-warning "attempt to free a non-heap object" } */ + free (L"abcd"); /* { dg-warning "attempt to free a non-heap object" } */ +} diff --git a/gcc/testsuite/gcc.dg/free-2.c b/gcc/testsuite/gcc.dg/free-2.c new file mode 100644 index 00000000000..eb94651311b --- /dev/null +++ b/gcc/testsuite/gcc.dg/free-2.c @@ -0,0 +1,26 @@ +/* PR c/36970 */ +/* { dg-do compile } */ +/* { dg-options "-O0" } */ + +extern void free (void *); + +char *p, buf3[10], d; +struct S { char a; int b; } *r; + +void foo (void) +{ + char buf[10], buf2[10], c; + static char buf4[10], e; + char *q = buf; + free (p); + free (q); /* At -O0 no warning is reported here. */ + free (buf2); /* { dg-warning "attempt to free a non-heap object" } */ + free (&c); /* { dg-warning "attempt to free a non-heap object" } */ + free (buf3); /* { dg-warning "attempt to free a non-heap object" } */ + free (&d); /* { dg-warning "attempt to free a non-heap object" } */ + free (buf4); /* { dg-warning "attempt to free a non-heap object" } */ + free (&e); /* { dg-warning "attempt to free a non-heap object" } */ + free (&r->a); + free ("abcd"); /* { dg-warning "attempt to free a non-heap object" } */ + free (L"abcd"); /* { dg-warning "attempt to free a non-heap object" } */ +} -- 2.30.2