[llvm] aa5bec0 - [ASan] Prevent assert from scalable vectors in FunctionStackPoisoner. (#155357)

[via llvm-commits]

Author: David Green
Date: 2025-08-27T09:00:52+01:00
New Revision: aa5bec0a6274ebe873cc60238206730929e4dd37

URL: https://github.com/llvm/llvm-project/commit/aa5bec0a6274ebe873cc60238206730929e4dd37
DIFF: https://github.com/llvm/llvm-project/commit/aa5bec0a6274ebe873cc60238206730929e4dd37.diff

LOG: [ASan] Prevent assert from scalable vectors in FunctionStackPoisoner. (#155357)

This has recently started causing 'Invalid size request on a scalable
vector.'

Added: 
    llvm/test/Instrumentation/AddressSanitizer/asan-scalable-vector.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 50258af5e26c3..42c3d4a4f4c46 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1219,7 +1219,9 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
 
     std::optional<TypeSize> Size = AI->getAllocationSize(AI->getDataLayout());
     // Check that size is known and can be stored in IntptrTy.
-    if (!Size || !ConstantInt::isValueValidForType(IntptrTy, *Size))
+    // TODO: Add support for scalable vectors if possible.
+    if (!Size || Size->isScalable() ||
+        !ConstantInt::isValueValidForType(IntptrTy, *Size))
       return;
 
     bool DoPoison = (ID == Intrinsic::lifetime_end);

diff  --git a/llvm/test/Instrumentation/AddressSanitizer/asan-scalable-vector.ll b/llvm/test/Instrumentation/AddressSanitizer/asan-scalable-vector.ll
new file mode 100644
index 0000000000000..6a841f2d399c0
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/asan-scalable-vector.ll
@@ -0,0 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes='asan<use-after-scope>' -S | FileCheck %s
+
+define void @test() #1 {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[CTX_PG:%.*]] = alloca <vscale x 16 x i1>, align 2
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0(ptr [[CTX_PG]])
+; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr inttoptr (i64 17592186044416 to ptr), align 1
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i8 [[TMP0]], 0
+; CHECK-NEXT:    br i1 [[TMP1]], label %[[BB2:.*]], label %[[BB3:.*]]
+; CHECK:       [[BB2]]:
+; CHECK-NEXT:    call void @__asan_report_store8(i64 0) #[[ATTR4:[0-9]+]]
+; CHECK-NEXT:    unreachable
+; CHECK:       [[BB3]]:
+; CHECK-NEXT:    store ptr [[CTX_PG]], ptr null, align 8
+; CHECK-NEXT:    ret void
+;
+entry:
+  %ctx_pg = alloca <vscale x 16 x i1>, align 2
+  call void @llvm.lifetime.start.p0(ptr %ctx_pg)
+  store ptr %ctx_pg, ptr null, align 8
+  ret void
+}
+
+attributes #1 = { sanitize_address }