[compiler-rt] r318717 - [sanitizers] Add init function to set alignment of low level allocator

[Walter Lee via llvm-commits]

Author: waltl
Date: Mon Nov 20 17:01:32 2017
New Revision: 318717

URL: http://llvm.org/viewvc/llvm-project?rev=318717&view=rev
Log:
[sanitizers] Add init function to set alignment of low level allocator

ASan requires that the min alignment be at least the shadow
granularity, so add an init function to do that.

Differential Revision: https://reviews.llvm.org/D39473

Modified:
    compiler-rt/trunk/lib/asan/asan_rtl.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h

Modified: compiler-rt/trunk/lib/asan/asan_rtl.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_rtl.cc?rev=318717&r1=318716&r2=318717&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_rtl.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_rtl.cc Mon Nov 20 17:01:32 2017
@@ -407,6 +407,7 @@ static void AsanInitInternal() {
   MaybeReexec();
 
   // Setup internal allocator callback.
+  SetLowLevelAllocateMinAlignment(SHADOW_GRANULARITY);
   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 
   InitializeAsanInterceptors();

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.cc?rev=318717&r1=318716&r2=318717&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.cc Mon Nov 20 17:01:32 2017
@@ -178,11 +178,13 @@ void InternalFree(void *addr, InternalAl
 }
 
 // LowLevelAllocator
+constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
+static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
 static LowLevelAllocateCallback low_level_alloc_callback;
 
 void *LowLevelAllocator::Allocate(uptr size) {
   // Align allocation size.
-  size = RoundUpTo(size, 8);
+  size = RoundUpTo(size, low_level_alloc_min_alignment);
   if (allocated_end_ - allocated_current_ < (sptr)size) {
     uptr size_to_allocate = Max(size, GetPageSizeCached());
     allocated_current_ =
@@ -199,6 +201,11 @@ void *LowLevelAllocator::Allocate(uptr s
   return res;
 }
 
+void SetLowLevelAllocateMinAlignment(uptr alignment) {
+  CHECK(IsPowerOfTwo(alignment));
+  low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
+}
+
 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
   low_level_alloc_callback = callback;
 }

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=318717&r1=318716&r2=318717&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Mon Nov 20 17:01:32 2017
@@ -206,6 +206,8 @@ class LowLevelAllocator {
   char *allocated_end_;
   char *allocated_current_;
 };
+// Set the min alignment of LowLevelAllocator to at least alignment.
+void SetLowLevelAllocateMinAlignment(uptr alignment);
 typedef void (*LowLevelAllocateCallback)(uptr ptr, uptr size);
 // Allows to register tool-specific callbacks for LowLevelAllocator.
 // Passing NULL removes the callback.