release/21.x: [clang] Align cleanup structs to prevent SIGBUS on sparc32 (#152866) #154002
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@efriedma-quic What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-clang-codegen Author: None (llvmbot) ChangesBackport 8071d27 Requested by: @brad0 Full diff: https://github.com/llvm/llvm-project/pull/154002.diff 3 Files Affected:
diff --git a/clang/include/clang/AST/APValue.h b/clang/include/clang/AST/APValue.h
index 9999a30c51ade..cb942ea865e2d 100644
--- a/clang/include/clang/AST/APValue.h
+++ b/clang/include/clang/AST/APValue.h
@@ -143,7 +143,7 @@ class APValue {
AddrLabelDiff
};
- class LValueBase {
+ class alignas(uint64_t) LValueBase {
typedef llvm::PointerUnion<const ValueDecl *, const Expr *, TypeInfoLValue,
DynamicAllocLValue>
PtrTy;
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 6c32c98cec011..f5ac9f387c641 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -727,7 +727,7 @@ class CodeGenFunction : public CodeGenTypeCache {
};
/// Header for data within LifetimeExtendedCleanupStack.
- struct LifetimeExtendedCleanupHeader {
+ struct alignas(uint64_t) LifetimeExtendedCleanupHeader {
/// The size of the following cleanup object.
unsigned Size;
/// The kind of cleanup to push.
@@ -949,7 +949,8 @@ class CodeGenFunction : public CodeGenTypeCache {
LifetimeExtendedCleanupStack.size() + sizeof(Header) + Header.Size +
(Header.IsConditional ? sizeof(ActiveFlag) : 0));
- static_assert(sizeof(Header) % alignof(T) == 0,
+ static_assert((alignof(LifetimeExtendedCleanupHeader) == alignof(T)) &&
+ (alignof(T) == alignof(RawAddress)),
"Cleanup will be allocated on misaligned address");
char *Buffer = &LifetimeExtendedCleanupStack[OldSize];
new (Buffer) LifetimeExtendedCleanupHeader(Header);
diff --git a/clang/lib/CodeGen/EHScopeStack.h b/clang/lib/CodeGen/EHScopeStack.h
index ed11dc2bb05d7..54f6ceaa52b95 100644
--- a/clang/lib/CodeGen/EHScopeStack.h
+++ b/clang/lib/CodeGen/EHScopeStack.h
@@ -143,7 +143,7 @@ class EHScopeStack {
///
/// Cleanup implementations should generally be declared in an
/// anonymous namespace.
- class Cleanup {
+ class alignas(uint64_t) Cleanup {
// Anchor the construction vtable.
virtual void anchor();
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@llvm/pr-subscribers-clang Author: None (llvmbot) ChangesBackport 8071d27 Requested by: @brad0 Full diff: https://github.com/llvm/llvm-project/pull/154002.diff 3 Files Affected:
diff --git a/clang/include/clang/AST/APValue.h b/clang/include/clang/AST/APValue.h
index 9999a30c51ade..cb942ea865e2d 100644
--- a/clang/include/clang/AST/APValue.h
+++ b/clang/include/clang/AST/APValue.h
@@ -143,7 +143,7 @@ class APValue {
AddrLabelDiff
};
- class LValueBase {
+ class alignas(uint64_t) LValueBase {
typedef llvm::PointerUnion<const ValueDecl *, const Expr *, TypeInfoLValue,
DynamicAllocLValue>
PtrTy;
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 6c32c98cec011..f5ac9f387c641 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -727,7 +727,7 @@ class CodeGenFunction : public CodeGenTypeCache {
};
/// Header for data within LifetimeExtendedCleanupStack.
- struct LifetimeExtendedCleanupHeader {
+ struct alignas(uint64_t) LifetimeExtendedCleanupHeader {
/// The size of the following cleanup object.
unsigned Size;
/// The kind of cleanup to push.
@@ -949,7 +949,8 @@ class CodeGenFunction : public CodeGenTypeCache {
LifetimeExtendedCleanupStack.size() + sizeof(Header) + Header.Size +
(Header.IsConditional ? sizeof(ActiveFlag) : 0));
- static_assert(sizeof(Header) % alignof(T) == 0,
+ static_assert((alignof(LifetimeExtendedCleanupHeader) == alignof(T)) &&
+ (alignof(T) == alignof(RawAddress)),
"Cleanup will be allocated on misaligned address");
char *Buffer = &LifetimeExtendedCleanupStack[OldSize];
new (Buffer) LifetimeExtendedCleanupHeader(Header);
diff --git a/clang/lib/CodeGen/EHScopeStack.h b/clang/lib/CodeGen/EHScopeStack.h
index ed11dc2bb05d7..54f6ceaa52b95 100644
--- a/clang/lib/CodeGen/EHScopeStack.h
+++ b/clang/lib/CodeGen/EHScopeStack.h
@@ -143,7 +143,7 @@ class EHScopeStack {
///
/// Cleanup implementations should generally be declared in an
/// anonymous namespace.
- class Cleanup {
+ class alignas(uint64_t) Cleanup {
// Anchor the construction vtable.
virtual void anchor();
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ping @efriedma-quic for review. |
efriedma-quic
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efriedma-quic
approved these changes
Aug 21, 2025
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…m#152866) The cleanup structs expect that pointers and (u)int64_t have the same alignment requirements, which isn't true on sparc32, which causes SIGBUSes. See also: llvm#66620 (cherry picked from commit 8071d27)
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@brad0 (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Backport 8071d27
Requested by: @brad0