[PATCH] D39473: [sanitizers] Add init function to set alignment of low level allocator

[Walter Lee via Phabricator via llvm-commits]

waltl updated this revision to Diff 123633.
waltl edited the summary of this revision.
waltl added a comment.

Address CR comments


https://reviews.llvm.org/D39473

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


Index: compiler-rt/lib/sanitizer_common/sanitizer_common.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -205,6 +205,8 @@
   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.
Index: compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc
+++ compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc
@@ -178,11 +178,13 @@
 }
 
 // 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 @@
   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;
 }
Index: compiler-rt/lib/asan/asan_rtl.cc
===================================================================
--- compiler-rt/lib/asan/asan_rtl.cc
+++ compiler-rt/lib/asan/asan_rtl.cc
@@ -407,6 +407,7 @@
   MaybeReexec();
 
   // Setup internal allocator callback.
+  SetLowLevelAllocateMinAlignment(SHADOW_GRANULARITY);
   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 
   InitializeAsanInterceptors();


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