diff options
| author | Eric Botcazou <ebotcazou@adacore.com> | 2022-10-14 00:55:40 +0200 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@adacore.com> | 2022-10-14 00:59:31 +0200 |
| commit | c26d335fffc689051ee5826455c9d54d1fcf1816 (patch) | |
| tree | e535bd578278e70ec247442af67c9aa835359ede | |
| parent | 537e08cfad04e79fb97d368e397cfc7e782865ec (diff) | |
| download | gcc-c26d335fffc689051ee5826455c9d54d1fcf1816.zip gcc-c26d335fffc689051ee5826455c9d54d1fcf1816.tar.gz gcc-c26d335fffc689051ee5826455c9d54d1fcf1816.tar.bz2 | |
Fix bogus -Wstringop-overflow warning
If you compile the testcase with -O2 -fno-inline -Wall, you get:
In function 'process_array3':
cc1: warning: 'process_array4' accessing 4 bytes in a region of size 3 [-
Wstringop-overflow=]
cc1: note: referencing argument 1 of type 'char[4]'
t.c:6:6: note: in a call to function 'process_array4'
6 | void process_array4 (char a[4], int n)
| ^~~~~~~~~~~~~~
cc1: warning: 'process_array4' accessing 4 bytes in a region of size 3 [-
Wstringop-overflow=]
cc1: note: referencing argument 1 of type 'char[4]'
t.c:6:6: note: in a call to function 'process_array4'
That's because the ICF IPA pass has identified the two functions and turned
process_array3 into a wrapper of process_array4.
gcc/
* gimple-ssa-warn-access.cc (pass_waccess::check_call): Return
early for calls made from thunks.
gcc/testsuite/
* gcc.dg/Wstringop-overflow-89.c: New test.
| -rw-r--r-- | gcc/gimple-ssa-warn-access.cc | 8 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/Wstringop-overflow-89.c | 16 |
2 files changed, 22 insertions, 2 deletions
diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc index 04aa849..59a7053 100644 --- a/gcc/gimple-ssa-warn-access.cc +++ b/gcc/gimple-ssa-warn-access.cc @@ -4291,14 +4291,18 @@ pass_waccess::check_pointer_uses (gimple *stmt, tree ptr, void pass_waccess::check_call (gcall *stmt) { - if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) - check_builtin (stmt); + /* Skip special calls generated by the compiler. */ + if (gimple_call_from_thunk_p (stmt)) + return; /* .ASAN_MARK doesn't access any vars, only modifies shadow memory. */ if (gimple_call_internal_p (stmt) && gimple_call_internal_fn (stmt) == IFN_ASAN_MARK) return; + if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) + check_builtin (stmt); + if (!m_early_checks_p) if (tree callee = gimple_call_fndecl (stmt)) { diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c new file mode 100644 index 0000000..ba25a93 --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fno-inline -Wall" } */ + +extern void process (char); + +void process_array4 (char a[4], int n) +{ + for (int i = 0; i < n; i++) + process (a[i]); +} + +void process_array3 (char a[3], int n) +{ + for (int i = 0; i < n; i++) + process (a[i]); +} |