[MSAN] Handle array alloca with non-i64 size specification

The array size specification of the an alloca can be any integer,
so zext or trunc it to intptr before attempting to multiply it
with an intptr constant.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D131846

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -3948,7 +3948,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     uint64_t TypeSize = DL.getTypeAllocSize(I.getAllocatedType());
     Value *Len = ConstantInt::get(MS.IntptrTy, TypeSize);
     if (I.isArrayAllocation())
-      Len = IRB.CreateMul(Len, I.getArraySize());
+      Len = IRB.CreateMul(Len,
+                          IRB.CreateZExtOrTrunc(I.getArraySize(), MS.IntptrTy));
 
     if (MS.CompileKernel)
       poisonAllocaKmsan(I, IRB, Len);

llvm/test/Instrumentation/MemorySanitizer/alloca.ll

@@ -65,6 +65,20 @@ entry:
 ; KMSAN: call void @__msan_poison_alloca(i8* {{.*}}, i64 20,
 ; CHECK: ret void
 
+define void @array32() sanitize_memory {
+entry:
+  %x = alloca i32, i32 5, align 4
+  ret void
+}
+
+; CHECK-LABEL: define void @array32(
+; INLINE: call void @llvm.memset.p0i8.i64(i8* align 4 {{.*}}, i8 -1, i64 20, i1 false)
+; CALL: call void @__msan_poison_stack(i8* {{.*}}, i64 20)
+; ORIGIN: call void @__msan_set_alloca_origin_with_descr(i8* {{.*}}, i64 20,
+; ORIGIN-LEAN: call void @__msan_set_alloca_origin_no_descr(i8* {{.*}}, i64 20,
+; KMSAN: call void @__msan_poison_alloca(i8* {{.*}}, i64 20,
+; CHECK: ret void
+
 define void @array_non_const(i64 %cnt) sanitize_memory {
 entry:
   %x = alloca i32, i64 %cnt, align 4
@@ -80,6 +94,22 @@ entry:
 ; KMSAN: call void @__msan_poison_alloca(i8* {{.*}}, i64 %[[A]],
 ; CHECK: ret void
 
+define void @array_non_const32(i32 %cnt) sanitize_memory {
+entry:
+  %x = alloca i32, i32 %cnt, align 4
+  ret void
+}
+
+; CHECK-LABEL: define void @array_non_const32(
+; CHECK: %[[Z:.*]] = zext i32 %cnt to i64
+; CHECK: %[[A:.*]] = mul i64 4, %[[Z]]
+; INLINE: call void @llvm.memset.p0i8.i64(i8* align 4 {{.*}}, i8 -1, i64 %[[A]], i1 false)
+; CALL: call void @__msan_poison_stack(i8* {{.*}}, i64 %[[A]])
+; ORIGIN: call void @__msan_set_alloca_origin_with_descr(i8* {{.*}}, i64 %[[A]],
+; ORIGIN-LEAN: call void @__msan_set_alloca_origin_no_descr(i8* {{.*}}, i64 %[[A]],
+; KMSAN: call void @__msan_poison_alloca(i8* {{.*}}, i64 %[[A]],
+; CHECK: ret void
+
 ; Check that the local is unpoisoned in the absence of sanitize_memory
 define void @unpoison_local() {
 entry: