[PATCH] D39470: [asan] Fix size/alignment issues with non-default shadow scale

[Walter Lee via Phabricator via llvm-commits]

waltl updated this revision to Diff 122691.
waltl added a comment.

Add test to verify metadata_array alignment


https://reviews.llvm.org/D39470

Files:
  llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
  llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll


Index: llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
===================================================================
--- llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
+++ llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
@@ -24,6 +24,8 @@
 ; Check that location descriptors and global names were passed into __asan_register_globals:
 ; CHECK: i64 ptrtoint ([7 x i8]* [[VARNAME]] to i64)
 ; CHECK: i64 ptrtoint ({ [22 x i8]*, i32, i32 }* [[LOCDESCR]] to i64)
+; Check alignment of metadata_array.
+; CHECK-S5-SAME: {{align 32$}}
 
 ; Function Attrs: nounwind sanitize_address
 define internal void @__cxx_global_var_init() #0 section ".text.startup" {
Index: llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1974,6 +1974,8 @@
   auto AllGlobals = new GlobalVariable(
       M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
       ConstantArray::get(ArrayOfGlobalStructTy, MetadataInitializers), "");
+  if (Mapping.Scale > 3)
+    AllGlobals->setAlignment(1ULL << Mapping.Scale);
 
   IRB.CreateCall(AsanRegisterGlobals,
                  {IRB.CreatePointerCast(AllGlobals, IntptrTy),
@@ -2797,9 +2799,10 @@
 
   // Minimal header size (left redzone) is 4 pointers,
   // i.e. 32 bytes on 64-bit platforms and 16 bytes in 32-bit platforms.
-  size_t MinHeaderSize = ASan.LongSize / 2;
+  size_t Granularity = 1ULL << Mapping.Scale;
+  size_t MinHeaderSize = std::max((size_t)ASan.LongSize / 2, Granularity);
   const ASanStackFrameLayout &L =
-      ComputeASanStackFrameLayout(SVD, 1ULL << Mapping.Scale, MinHeaderSize);
+      ComputeASanStackFrameLayout(SVD, Granularity, MinHeaderSize);
 
   // Build AllocaToSVDMap for ASanStackVariableDescription lookup.
   DenseMap<const AllocaInst *, ASanStackVariableDescription *> AllocaToSVDMap;


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