[llvm-branch-commits] [llvm] release/22.x: [SafeStack] Fix crashing with scalable TypeSizes (#180547) (PR #203306)

[Jakob Koschel via llvm-branch-commits]

jakos-sec wrote:

@brad0: Looks like there is another code change that fixed another instance of the bug (https://github.com/llvm/llvm-project/pull/176486).

In particular this change is needed for `llvm/lib/CodeGen/SafeStack.cpp`:

```
diff --git a/llvm/lib/CodeGen/SafeStack.cpp b/llvm/lib/CodeGen/SafeStack.cpp
index 33ffd94e4f8f..d8c727df2a39 100644
--- a/llvm/lib/CodeGen/SafeStack.cpp
+++ b/llvm/lib/CodeGen/SafeStack.cpp
@@ -198,14 +198,10 @@ public:
 };

 uint64_t SafeStack::getStaticAllocaAllocationSize(const AllocaInst* AI) {
-  uint64_t Size = DL.getTypeAllocSize(AI->getAllocatedType());
-  if (AI->isArrayAllocation()) {
-    auto C = dyn_cast<ConstantInt>(AI->getArraySize());
-    if (!C)
-      return 0;
-    Size *= C->getZExtValue();
-  }
-  return Size;
+  if (auto Size = AI->getAllocationSize(DL))
+    if (Size->isFixed())
+      return Size->getFixedValue();
+  return 0;
 }
```

https://github.com/llvm/llvm-project/pull/203306