[llvm] 9f4047e - [ASan] Handle allocas in non-default address spaces (#213764)

[via llvm-commits]

Author: npanchen
Date: 2026-08-04T09:27:54-04:00
New Revision: 9f4047e46e6be19672f7635a174b5cd7b0bd9f1d

URL: https://github.com/llvm/llvm-project/commit/9f4047e46e6be19672f7635a174b5cd7b0bd9f1d
DIFF: https://github.com/llvm/llvm-project/commit/9f4047e46e6be19672f7635a174b5cd7b0bd9f1d.diff

LOG: [ASan] Handle allocas in non-default address spaces (#213764)

Do addrspace cast for allocas that live in address space different from
the datalayout's alloca address space, otherwise ASan will crash during
use replacement

Added: 
    llvm/test/Instrumentation/AddressSanitizer/alloca-addrspace.ll

Modified: 
    llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 2fae7d8c15ff3..d358318195265 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -3734,6 +3734,8 @@ void FunctionStackPoisoner::processStaticAllocas() {
     replaceDbgDeclare(AI, LocalStackBaseAlloca, DIB, DIExprFlags, Desc.Offset);
     Value *NewAllocaPtr = IRB.CreatePtrAdd(
         LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset));
+    if (NewAllocaPtr->getType() != AI->getType())
+      NewAllocaPtr = IRB.CreateAddrSpaceCast(NewAllocaPtr, AI->getType());
     AI->replaceAllUsesWith(NewAllocaPtr);
     NewAllocaPtrs.push_back(NewAllocaPtr);
   }

diff  --git a/llvm/test/Instrumentation/AddressSanitizer/alloca-addrspace.ll b/llvm/test/Instrumentation/AddressSanitizer/alloca-addrspace.ll
new file mode 100644
index 0000000000000..5553235352bef
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/alloca-addrspace.ll
@@ -0,0 +1,30 @@
+; RUN: opt < %s -passes=asan -S | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @use(ptr)
+
+; CHECK-LABEL: define ptr addrspace(3) @only_addrspace_alloca()
+; CHECK:         %[[BASE:[0-9]+]] = phi ptr
+; CHECK:         %[[SLOT:[0-9]+]] = getelementptr i8, ptr %[[BASE]], i64 32
+; CHECK-NEXT:    %[[CAST:[0-9]+]] = addrspacecast ptr %[[SLOT]] to ptr addrspace(3)
+; CHECK:         ret ptr addrspace(3) %[[CAST]]
+define ptr addrspace(3) @only_addrspace_alloca() sanitize_address {
+  %p = alloca float, align 4, addrspace(3)
+  ret ptr addrspace(3) %p
+}
+
+; CHECK-LABEL: define ptr addrspace(3) @mixed_allocas()
+; CHECK:         %[[BASE:[0-9]+]] = phi ptr
+; CHECK:         %[[QSLOT:[0-9]+]] = getelementptr i8, ptr %[[BASE]], i64 32
+; CHECK-NEXT:    %[[PSLOT:[0-9]+]] = getelementptr i8, ptr %[[BASE]], i64 48
+; CHECK-NEXT:    %[[PCAST:[0-9]+]] = addrspacecast ptr %[[PSLOT]] to ptr addrspace(3)
+; CHECK:         call void @use(ptr %[[QSLOT]])
+; CHECK:         ret ptr addrspace(3) %[[PCAST]]
+define ptr addrspace(3) @mixed_allocas() sanitize_address {
+  %q = alloca i32, align 4
+  %p = alloca float, align 4, addrspace(3)
+  call void @use(ptr %q)
+  ret ptr addrspace(3) %p
+}