diff options
| author | Etienne Bergeron <etienneb@google.com> | 2016-09-21 16:32:14 +0000 |
|---|---|---|
| committer | Etienne Bergeron <etienneb@google.com> | 2016-09-21 16:32:14 +0000 |
| commit | 4fd2747b747412418b499475ff7122842c150015 (patch) | |
| tree | c3c330d8094627940cbcecb747540a6d593addb5 /lib/asan/asan_rtl.cc | |
| parent | 1d7390eea36b7deee5c5c19e3a88803a322e5f92 (diff) | |
[compiler-rt] Fix Asan build on Android
Summary:
The dynamic shadow code is not detected correctly on Android.
The android shadow seems to start at address zero.
The bug is introduced here:
https://reviews.llvm.org/D23363
Started here: https://build.chromium.org/p/chromium.fyi/builders/ClangToTAndroidASan/builds/4029
Likely due to an asan runtime change, filed https://llvm.org/bugs/show_bug.cgi?id=30462
From asan_mapping.h:
```
#if SANITIZER_WORDSIZE == 32
# if SANITIZER_ANDROID
# define SHADOW_OFFSET (0) <<---- HERE
# elif defined(__mips__)
```
Shadow address on android is 0.
From asan_rtl.c:
```
if (shadow_start == 0) {
[...]
shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity);
}
```
We assumed that 0 is dynamic address.
On windows, the address was determined with:
```
# elif SANITIZER_WINDOWS64
# define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
# else
```
and __asan_shadow_memory_dynamic_address is initially zero.
Reviewers: rnk, eugenis, vitalybuka
Subscribers: kcc, tberghammer, danalbert, kubabrecka, dberris, llvm-commits, chrisha
Differential Revision: https://reviews.llvm.org/D24768
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@282085 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/asan/asan_rtl.cc')
| -rw-r--r-- | lib/asan/asan_rtl.cc | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/asan/asan_rtl.cc b/lib/asan/asan_rtl.cc index 1d676bd0d..c232db5cd 100644 --- a/lib/asan/asan_rtl.cc +++ b/lib/asan/asan_rtl.cc @@ -461,9 +461,18 @@ static void AsanInitInternal() { ReplaceSystemMalloc(); - __asan_shadow_memory_dynamic_address = 0; + // Set the shadow memory address to uninitialized. + __asan_shadow_memory_dynamic_address = kDefaultShadowSentinel; + uptr shadow_start = kLowShadowBeg; - if (shadow_start == 0) { + // Detect if a dynamic shadow address must used and find a available location + // when necessary. When dynamic address is used, the macro |kLowShadowBeg| + // expands to |__asan_shadow_memory_dynamic_address| which is + // |kDefaultShadowSentinel|. + if (shadow_start == kDefaultShadowSentinel) { + __asan_shadow_memory_dynamic_address = 0; + CHECK_EQ(0, kLowShadowBeg); + uptr granularity = GetMmapGranularity(); uptr alignment = 8 * granularity; uptr left_padding = granularity; @@ -473,6 +482,7 @@ static void AsanInitInternal() { CHECK_NE((uptr)0, shadow_start); CHECK(IsAligned(shadow_start, alignment)); } + // Update the shadow memory address (potentially) used by instrumentation. __asan_shadow_memory_dynamic_address = shadow_start; if (kLowShadowBeg) |