[clang] Reapply "[clang][bytecode] Stack-allocate bottom function frame" (#12… (PR #125349)
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Sat Feb 1 07:53:23 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Timm Baeder (tbaederr)
<details>
<summary>Changes</summary>
…5325)
Move the BottomFrame to InterpState instead.
---
Full diff: https://github.com/llvm/llvm-project/pull/125349.diff
7 Files Affected:
- (modified) clang/lib/AST/ByteCode/Context.cpp (+1-4)
- (modified) clang/lib/AST/ByteCode/EvalEmitter.cpp (+1-5)
- (modified) clang/lib/AST/ByteCode/Interp.h (+4-4)
- (modified) clang/lib/AST/ByteCode/InterpFrame.cpp (+14-6)
- (modified) clang/lib/AST/ByteCode/InterpFrame.h (+12)
- (modified) clang/lib/AST/ByteCode/InterpState.cpp (+10-2)
- (modified) clang/lib/AST/ByteCode/InterpState.h (+4)
``````````diff
diff --git a/clang/lib/AST/ByteCode/Context.cpp b/clang/lib/AST/ByteCode/Context.cpp
index a322700fc0d229..aa434d5c85921f 100644
--- a/clang/lib/AST/ByteCode/Context.cpp
+++ b/clang/lib/AST/ByteCode/Context.cpp
@@ -212,14 +212,11 @@ const llvm::fltSemantics &Context::getFloatSemantics(QualType T) const {
bool Context::Run(State &Parent, const Function *Func) {
{
- InterpState State(Parent, *P, Stk, *this);
- State.Current = new InterpFrame(State, Func, /*Caller=*/nullptr, CodePtr(),
- Func->getArgSize());
+ InterpState State(Parent, *P, Stk, *this, Func);
if (Interpret(State)) {
assert(Stk.empty());
return true;
}
-
// State gets destroyed here, so the Stk.clear() below doesn't accidentally
// remove values the State's destructor might access.
}
diff --git a/clang/lib/AST/ByteCode/EvalEmitter.cpp b/clang/lib/AST/ByteCode/EvalEmitter.cpp
index 8134bbf270363e..95149efbea9921 100644
--- a/clang/lib/AST/ByteCode/EvalEmitter.cpp
+++ b/clang/lib/AST/ByteCode/EvalEmitter.cpp
@@ -17,11 +17,7 @@ using namespace clang::interp;
EvalEmitter::EvalEmitter(Context &Ctx, Program &P, State &Parent,
InterpStack &Stk)
- : Ctx(Ctx), P(P), S(Parent, P, Stk, Ctx, this), EvalResult(&Ctx) {
- // Create a dummy frame for the interpreter which does not have locals.
- S.Current =
- new InterpFrame(S, /*Func=*/nullptr, /*Caller=*/nullptr, CodePtr(), 0);
-}
+ : Ctx(Ctx), P(P), S(Parent, P, Stk, Ctx, this), EvalResult(&Ctx) {}
EvalEmitter::~EvalEmitter() {
for (auto &[K, V] : Locals) {
diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index 063970afec9e35..2a39e3932077f5 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -325,11 +325,11 @@ bool Ret(InterpState &S, CodePtr &PC) {
if (InterpFrame *Caller = S.Current->Caller) {
PC = S.Current->getRetPC();
- delete S.Current;
+ InterpFrame::free(S.Current);
S.Current = Caller;
S.Stk.push<T>(Ret);
} else {
- delete S.Current;
+ InterpFrame::free(S.Current);
S.Current = nullptr;
// The topmost frame should come from an EvalEmitter,
// which has its own implementation of the Ret<> instruction.
@@ -345,10 +345,10 @@ inline bool RetVoid(InterpState &S, CodePtr &PC) {
if (InterpFrame *Caller = S.Current->Caller) {
PC = S.Current->getRetPC();
- delete S.Current;
+ InterpFrame::free(S.Current);
S.Current = Caller;
} else {
- delete S.Current;
+ InterpFrame::free(S.Current);
S.Current = nullptr;
}
return true;
diff --git a/clang/lib/AST/ByteCode/InterpFrame.cpp b/clang/lib/AST/ByteCode/InterpFrame.cpp
index 48a3db055c6c9b..89fc7a4515d641 100644
--- a/clang/lib/AST/ByteCode/InterpFrame.cpp
+++ b/clang/lib/AST/ByteCode/InterpFrame.cpp
@@ -23,11 +23,15 @@
using namespace clang;
using namespace clang::interp;
+InterpFrame::InterpFrame(InterpState &S)
+ : Caller(nullptr), S(S), Depth(0), Func(nullptr), RetPC(CodePtr()),
+ ArgSize(0), Args(nullptr), FrameOffset(0), IsBottom(true) {}
+
InterpFrame::InterpFrame(InterpState &S, const Function *Func,
InterpFrame *Caller, CodePtr RetPC, unsigned ArgSize)
: Caller(Caller), S(S), Depth(Caller ? Caller->Depth + 1 : 0), Func(Func),
RetPC(RetPC), ArgSize(ArgSize), Args(static_cast<char *>(S.Stk.top())),
- FrameOffset(S.Stk.size()) {
+ FrameOffset(S.Stk.size()), IsBottom(!Caller) {
if (!Func)
return;
@@ -73,11 +77,15 @@ InterpFrame::~InterpFrame() {
// When destroying the InterpFrame, call the Dtor for all block
// that haven't been destroyed via a destroy() op yet.
// This happens when the execution is interruped midway-through.
- if (Func) {
- for (auto &Scope : Func->scopes()) {
- for (auto &Local : Scope.locals()) {
- S.deallocate(localBlock(Local.Offset));
- }
+ destroyScopes();
+}
+
+void InterpFrame::destroyScopes() {
+ if (!Func)
+ return;
+ for (auto &Scope : Func->scopes()) {
+ for (auto &Local : Scope.locals()) {
+ S.deallocate(localBlock(Local.Offset));
}
}
}
diff --git a/clang/lib/AST/ByteCode/InterpFrame.h b/clang/lib/AST/ByteCode/InterpFrame.h
index 7cfc3ac68b4f3e..360e6bff12327a 100644
--- a/clang/lib/AST/ByteCode/InterpFrame.h
+++ b/clang/lib/AST/ByteCode/InterpFrame.h
@@ -28,6 +28,9 @@ class InterpFrame final : public Frame {
/// The frame of the previous function.
InterpFrame *Caller;
+ /// Bottom Frame.
+ InterpFrame(InterpState &S);
+
/// Creates a new frame for a method call.
InterpFrame(InterpState &S, const Function *Func, InterpFrame *Caller,
CodePtr RetPC, unsigned ArgSize);
@@ -42,9 +45,15 @@ class InterpFrame final : public Frame {
/// Destroys the frame, killing all live pointers to stack slots.
~InterpFrame();
+ static void free(InterpFrame *F) {
+ if (!F->isBottomFrame())
+ delete F;
+ }
+
/// Invokes the destructors for a scope.
void destroy(unsigned Idx);
void initScope(unsigned Idx);
+ void destroyScopes();
/// Describes the frame with arguments for diagnostic purposes.
void describe(llvm::raw_ostream &OS) const override;
@@ -119,6 +128,8 @@ class InterpFrame final : public Frame {
bool isStdFunction() const;
+ bool isBottomFrame() const { return IsBottom; }
+
void dump() const { dump(llvm::errs(), 0); }
void dump(llvm::raw_ostream &OS, unsigned Indent = 0) const;
@@ -167,6 +178,7 @@ class InterpFrame final : public Frame {
const size_t FrameOffset;
/// Mapping from arg offsets to their argument blocks.
llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Params;
+ bool IsBottom = false;
};
} // namespace interp
diff --git a/clang/lib/AST/ByteCode/InterpState.cpp b/clang/lib/AST/ByteCode/InterpState.cpp
index 287c3bd3bca3a5..70a2e9b62fc3ad 100644
--- a/clang/lib/AST/ByteCode/InterpState.cpp
+++ b/clang/lib/AST/ByteCode/InterpState.cpp
@@ -17,7 +17,14 @@ using namespace clang::interp;
InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
Context &Ctx, SourceMapper *M)
- : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr) {}
+ : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), BottomFrame(*this),
+ Current(&BottomFrame) {}
+
+InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
+ Context &Ctx, const Function *Func)
+ : Parent(Parent), M(nullptr), P(P), Stk(Stk), Ctx(Ctx),
+ BottomFrame(*this, Func, nullptr, CodePtr(), Func->getArgSize()),
+ Current(&BottomFrame) {}
bool InterpState::inConstantContext() const {
if (ConstantContextOverride)
@@ -27,11 +34,12 @@ bool InterpState::inConstantContext() const {
}
InterpState::~InterpState() {
- while (Current) {
+ while (Current && !Current->isBottomFrame()) {
InterpFrame *Next = Current->Caller;
delete Current;
Current = Next;
}
+ BottomFrame.destroyScopes();
while (DeadBlocks) {
DeadBlock *Next = DeadBlocks->Next;
diff --git a/clang/lib/AST/ByteCode/InterpState.h b/clang/lib/AST/ByteCode/InterpState.h
index 2a1311c86a2f2a..d6adfff1a713ac 100644
--- a/clang/lib/AST/ByteCode/InterpState.h
+++ b/clang/lib/AST/ByteCode/InterpState.h
@@ -37,6 +37,8 @@ class InterpState final : public State, public SourceMapper {
public:
InterpState(State &Parent, Program &P, InterpStack &Stk, Context &Ctx,
SourceMapper *M = nullptr);
+ InterpState(State &Parent, Program &P, InterpStack &Stk, Context &Ctx,
+ const Function *Func);
~InterpState();
@@ -134,6 +136,8 @@ class InterpState final : public State, public SourceMapper {
InterpStack &Stk;
/// Interpreter Context.
Context &Ctx;
+ /// Bottom function frame.
+ InterpFrame BottomFrame;
/// The current frame.
InterpFrame *Current = nullptr;
/// Source location of the evaluating expression
``````````
</details>
https://github.com/llvm/llvm-project/pull/125349
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