[clang] [clang][bytecode] Fix local destructor order (PR #107951)
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Mon Sep 9 19:15:07 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Timm Baeder (tbaederr)
<details>
<summary>Changes</summary>
Add appropriate scopes and use reverse-order iteration in LocalScope::emitDestructors().
---
Full diff: https://github.com/llvm/llvm-project/pull/107951.diff
3 Files Affected:
- (modified) clang/lib/AST/ByteCode/Compiler.cpp (+51-31)
- (modified) clang/lib/AST/ByteCode/Compiler.h (+5-3)
- (modified) clang/test/AST/ByteCode/cxx2a.cpp (+76)
``````````diff
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index fddd6db4f4814c..3ba9732a979244 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -115,22 +115,26 @@ template <class Emitter> class LoopScope final : public LabelScope<Emitter> {
LoopScope(Compiler<Emitter> *Ctx, LabelTy BreakLabel, LabelTy ContinueLabel)
: LabelScope<Emitter>(Ctx), OldBreakLabel(Ctx->BreakLabel),
OldContinueLabel(Ctx->ContinueLabel),
- OldLabelVarScope(Ctx->LabelVarScope) {
+ OldBreakVarScope(Ctx->BreakVarScope),
+ OldContinueVarScope(Ctx->ContinueVarScope) {
this->Ctx->BreakLabel = BreakLabel;
this->Ctx->ContinueLabel = ContinueLabel;
- this->Ctx->LabelVarScope = this->Ctx->VarScope;
+ this->Ctx->BreakVarScope = this->Ctx->VarScope;
+ this->Ctx->ContinueVarScope = this->Ctx->VarScope;
}
~LoopScope() {
this->Ctx->BreakLabel = OldBreakLabel;
this->Ctx->ContinueLabel = OldContinueLabel;
- this->Ctx->LabelVarScope = OldLabelVarScope;
+ this->Ctx->ContinueVarScope = OldContinueVarScope;
+ this->Ctx->BreakVarScope = OldBreakVarScope;
}
private:
OptLabelTy OldBreakLabel;
OptLabelTy OldContinueLabel;
- VariableScope<Emitter> *OldLabelVarScope;
+ VariableScope<Emitter> *OldBreakVarScope;
+ VariableScope<Emitter> *OldContinueVarScope;
};
// Sets the context for a switch scope, mapping labels.
@@ -145,18 +149,18 @@ template <class Emitter> class SwitchScope final : public LabelScope<Emitter> {
: LabelScope<Emitter>(Ctx), OldBreakLabel(Ctx->BreakLabel),
OldDefaultLabel(this->Ctx->DefaultLabel),
OldCaseLabels(std::move(this->Ctx->CaseLabels)),
- OldLabelVarScope(Ctx->LabelVarScope) {
+ OldLabelVarScope(Ctx->BreakVarScope) {
this->Ctx->BreakLabel = BreakLabel;
this->Ctx->DefaultLabel = DefaultLabel;
this->Ctx->CaseLabels = std::move(CaseLabels);
- this->Ctx->LabelVarScope = this->Ctx->VarScope;
+ this->Ctx->BreakVarScope = this->Ctx->VarScope;
}
~SwitchScope() {
this->Ctx->BreakLabel = OldBreakLabel;
this->Ctx->DefaultLabel = OldDefaultLabel;
this->Ctx->CaseLabels = std::move(OldCaseLabels);
- this->Ctx->LabelVarScope = OldLabelVarScope;
+ this->Ctx->BreakVarScope = OldLabelVarScope;
}
private:
@@ -4605,18 +4609,23 @@ bool Compiler<Emitter>::visitWhileStmt(const WhileStmt *S) {
this->fallthrough(CondLabel);
this->emitLabel(CondLabel);
- if (const DeclStmt *CondDecl = S->getConditionVariableDeclStmt())
- if (!visitDeclStmt(CondDecl))
- return false;
+ {
+ LocalScope<Emitter> CondScope(this);
+ if (const DeclStmt *CondDecl = S->getConditionVariableDeclStmt())
+ if (!visitDeclStmt(CondDecl))
+ return false;
- if (!this->visitBool(Cond))
- return false;
- if (!this->jumpFalse(EndLabel))
- return false;
+ if (!this->visitBool(Cond))
+ return false;
+ if (!this->jumpFalse(EndLabel))
+ return false;
- if (!this->visitStmt(Body))
- return false;
+ if (!this->visitStmt(Body))
+ return false;
+ if (!CondScope.destroyLocals())
+ return false;
+ }
if (!this->jump(CondLabel))
return false;
this->fallthrough(EndLabel);
@@ -4636,13 +4645,18 @@ template <class Emitter> bool Compiler<Emitter>::visitDoStmt(const DoStmt *S) {
this->fallthrough(StartLabel);
this->emitLabel(StartLabel);
+
{
+ LocalScope<Emitter> CondScope(this);
if (!this->visitStmt(Body))
return false;
this->fallthrough(CondLabel);
this->emitLabel(CondLabel);
if (!this->visitBool(Cond))
return false;
+
+ if (!CondScope.destroyLocals())
+ return false;
}
if (!this->jumpTrue(StartLabel))
return false;
@@ -4671,18 +4685,19 @@ bool Compiler<Emitter>::visitForStmt(const ForStmt *S) {
this->fallthrough(CondLabel);
this->emitLabel(CondLabel);
- if (const DeclStmt *CondDecl = S->getConditionVariableDeclStmt())
- if (!visitDeclStmt(CondDecl))
- return false;
+ {
+ LocalScope<Emitter> CondScope(this);
+ if (const DeclStmt *CondDecl = S->getConditionVariableDeclStmt())
+ if (!visitDeclStmt(CondDecl))
+ return false;
- if (Cond) {
- if (!this->visitBool(Cond))
- return false;
- if (!this->jumpFalse(EndLabel))
- return false;
- }
+ if (Cond) {
+ if (!this->visitBool(Cond))
+ return false;
+ if (!this->jumpFalse(EndLabel))
+ return false;
+ }
- {
if (Body && !this->visitStmt(Body))
return false;
@@ -4690,10 +4705,13 @@ bool Compiler<Emitter>::visitForStmt(const ForStmt *S) {
this->emitLabel(IncLabel);
if (Inc && !this->discard(Inc))
return false;
- }
+ if (!CondScope.destroyLocals())
+ return false;
+ }
if (!this->jump(CondLabel))
return false;
+
this->fallthrough(EndLabel);
this->emitLabel(EndLabel);
return true;
@@ -4760,7 +4778,7 @@ bool Compiler<Emitter>::visitBreakStmt(const BreakStmt *S) {
if (!BreakLabel)
return false;
- for (VariableScope<Emitter> *C = VarScope; C != LabelVarScope;
+ for (VariableScope<Emitter> *C = VarScope; C != BreakVarScope;
C = C->getParent())
C->emitDestruction();
return this->jump(*BreakLabel);
@@ -4771,8 +4789,8 @@ bool Compiler<Emitter>::visitContinueStmt(const ContinueStmt *S) {
if (!ContinueLabel)
return false;
- for (VariableScope<Emitter> *C = VarScope; C != LabelVarScope;
- C = C->getParent())
+ for (VariableScope<Emitter> *C = VarScope;
+ C && C->getParent() != ContinueVarScope; C = C->getParent())
C->emitDestruction();
return this->jump(*ContinueLabel);
}
@@ -4781,6 +4799,7 @@ template <class Emitter>
bool Compiler<Emitter>::visitSwitchStmt(const SwitchStmt *S) {
const Expr *Cond = S->getCond();
PrimType CondT = this->classifyPrim(Cond->getType());
+ LocalScope<Emitter> LS(this);
LabelTy EndLabel = this->getLabel();
OptLabelTy DefaultLabel = std::nullopt;
@@ -4844,7 +4863,8 @@ bool Compiler<Emitter>::visitSwitchStmt(const SwitchStmt *S) {
if (!this->visitStmt(S->getBody()))
return false;
this->emitLabel(EndLabel);
- return true;
+
+ return LS.destroyLocals();
}
template <class Emitter>
diff --git a/clang/lib/AST/ByteCode/Compiler.h b/clang/lib/AST/ByteCode/Compiler.h
index ac4c08c4d0ffb6..2dfa187713a803 100644
--- a/clang/lib/AST/ByteCode/Compiler.h
+++ b/clang/lib/AST/ByteCode/Compiler.h
@@ -409,10 +409,12 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
/// Switch case mapping.
CaseMap CaseLabels;
- /// Scope to cleanup until when chumping to one of the labels.
- VariableScope<Emitter> *LabelVarScope = nullptr;
+ /// Scope to cleanup until when we see a break statement.
+ VariableScope<Emitter> *BreakVarScope = nullptr;
/// Point to break to.
OptLabelTy BreakLabel;
+ /// Scope to cleanup until when we see a continue statement.
+ VariableScope<Emitter> *ContinueVarScope = nullptr;
/// Point to continue to.
OptLabelTy ContinueLabel;
/// Default case label.
@@ -533,7 +535,7 @@ template <class Emitter> class LocalScope : public VariableScope<Emitter> {
return true;
// Emit destructor calls for local variables of record
// type with a destructor.
- for (Scope::Local &Local : this->Ctx->Descriptors[*Idx]) {
+ for (Scope::Local &Local : llvm::reverse(this->Ctx->Descriptors[*Idx])) {
if (!Local.Desc->isPrimitive() && !Local.Desc->isPrimitiveArray()) {
if (!this->Ctx->emitGetPtrLocal(Local.Offset, E))
return false;
diff --git a/clang/test/AST/ByteCode/cxx2a.cpp b/clang/test/AST/ByteCode/cxx2a.cpp
index ad021b30cfd3cf..eaae978e011843 100644
--- a/clang/test/AST/ByteCode/cxx2a.cpp
+++ b/clang/test/AST/ByteCode/cxx2a.cpp
@@ -34,3 +34,79 @@ namespace Covariant {
constexpr const Covariant1 *cb1 = &cb;
static_assert(cb1->f()->a == 'Z');
}
+
+namespace DtorOrder {
+ struct Buf {
+ char buf[64];
+ int n = 0;
+ constexpr void operator+=(char c) { buf[n++] = c; }
+ constexpr bool operator==(const char *str) const {
+ if (str[n] != 0)
+ return false;
+
+ for (int i = 0; i < n; ++i) {
+ if (buf[n] != str[n])
+ return false;
+ }
+ return true;
+
+ return __builtin_memcmp(str, buf, n) == 0;
+ }
+ constexpr bool operator!=(const char *str) const { return !operator==(str); }
+ };
+
+ struct A {
+ constexpr A(Buf &buf, char c) : buf(buf), c(c) { buf += c; }
+ constexpr ~A() { buf += (c - 32);}
+ constexpr operator bool() const { return true; }
+ Buf &buf;
+ char c;
+ };
+
+ constexpr void abnormal_termination(Buf &buf) {
+ struct Indestructible {
+ constexpr ~Indestructible(); // not defined
+ };
+ A a(buf, 'a');
+ A(buf, 'b');
+ int n = 0;
+
+ for (A &&c = A(buf, 'c'); A d = A(buf, 'd'); A(buf, 'e')) {
+ switch (A f(buf, 'f'); A g = A(buf, 'g')) { // both-warning {{boolean}}
+ case false: {
+ A x(buf, 'x');
+ }
+
+ case true: {
+ A h(buf, 'h');
+ switch (n++) {
+ case 0:
+ break;
+ case 1:
+ continue;
+ case 2:
+ return;
+ }
+ break;
+ }
+
+ default:
+ Indestructible indest;
+ }
+
+ A j = (A(buf, 'i'), A(buf, 'j'));
+ }
+ }
+
+ constexpr bool check_abnormal_termination() {
+ Buf buf = {};
+ abnormal_termination(buf);
+ return buf ==
+ "abBc"
+ "dfgh" /*break*/ "HGFijIJeED"
+ "dfgh" /*continue*/ "HGFeED"
+ "dfgh" /*return*/ "HGFD"
+ "CA";
+ }
+ static_assert(check_abnormal_termination());
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/107951
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