[PATCH] D14817: [sanitizer] Avoid -Wmaybe-uninitialized related warnings when building ASan with GCC.

[Maxim Ostapenko via llvm-commits]

m.ostepenko created this revision.
m.ostepenko added reviewers: kcc, samsonov.
m.ostepenko added subscribers: llvm-commits, ygribov.
m.ostepenko set the repository for this revision to rL LLVM.
Herald added a subscriber: aemerson.

Hi!

Since "Use same shadow offset for aarch64"  and  "Enable optional ASan recovery" patches seem to work robustly in LLVM, I would like to perform another merge to GCC (GCC is on stage 3 now, but it is OK to perform merge now). For now, everything seems OK with library, except some warnings I got in GCC due to -Wmaybe-uninitialized switch:

```
/home/max/workspace/downloads/trunk/libsanitizer/asan/asan_interceptors.cc: In function ‘__sanitizer::uptr __interceptor_ptrace(int, int, void*, void*)’:
/home/max/workspace/downloads/trunk/libsanitizer/asan/asan_interceptors.cc:59:29: warning: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_len’ may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (__offset > __offset + __size) {                                 \
                             ^

In file included from /home/max/workspace/downloads/trunk/libsanitizer/asan/asan_interceptors.cc:196:0:
/home/max/workspace/downloads/trunk/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:2449:21: note: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_len’ was declared here
   __sanitizer_iovec local_iovec;
                     ^~~~~~~~~~~
```

This patch just adds proper default values to local variables in several places.

Repository:
  rL LLVM

http://reviews.llvm.org/D14817

Files:
  lib/sanitizer_common/sanitizer_common_interceptors.inc
  lib/sanitizer_common/sanitizer_posix.cc

Index: lib/sanitizer_common/sanitizer_posix.cc
===================================================================
--- lib/sanitizer_common/sanitizer_posix.cc
+++ lib/sanitizer_common/sanitizer_posix.cc
@@ -177,6 +177,7 @@
     case RdOnly: flags = O_RDONLY; break;
     case WrOnly: flags = O_WRONLY | O_CREAT; break;
     case RdWr: flags = O_RDWR | O_CREAT; break;
+    default: flags = O_RDONLY; break;
   }
   fd_t res = internal_open(filename, flags, 0660);
   if (internal_iserror(res, errno_p))
Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -2448,7 +2448,7 @@
 INTERCEPTOR(uptr, ptrace, int request, int pid, void *addr, void *data) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, ptrace, request, pid, addr, data);
-  __sanitizer_iovec local_iovec;
+  __sanitizer_iovec local_iovec = {0, 0};
 
   if (data) {
     if (request == ptrace_setregs)


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