[clang] [clang-repl] Names declared in if conditions and for-init statements are local to the inner context (C++ 3.3.2p4) (PR #84150)
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Wed Mar 6 03:03:01 PST 2024
Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>,
Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>,
Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>,
Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>,
Stefan =?utf-8?q?Gränitz?= <stefan.graenitz at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/84150 at github.com>
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Stefan Gränitz (weliveindetail)
<details>
<summary>Changes</summary>
A `TopLevelStmtDecl` must be a `DeclContext` itself to avoid variable definitions to be added to the outer `TranslationUnitDecl` context. Additionally, `ActOnForStmt()` requires a `CompoundScope` when processing a `NullStmt` body.
---
Full diff: https://github.com/llvm/llvm-project/pull/84150.diff
9 Files Affected:
- (modified) clang/include/clang/AST/Decl.h (+10-6)
- (modified) clang/include/clang/AST/DeclBase.h (+1)
- (modified) clang/include/clang/Basic/DeclNodes.td (+1-1)
- (modified) clang/include/clang/Sema/Sema.h (+2-1)
- (modified) clang/lib/AST/Decl.cpp (+8-3)
- (modified) clang/lib/AST/DeclBase.cpp (+1)
- (modified) clang/lib/Parse/ParseDecl.cpp (+16-8)
- (modified) clang/lib/Sema/SemaDecl.cpp (+13-3)
- (modified) clang/test/Interpreter/execute-stmts.cpp (+13-1)
``````````diff
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 61117cc5ce71f9..a5879591f4c659 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -4419,7 +4419,7 @@ class FileScopeAsmDecl : public Decl {
///
/// \note This is used in libInterpreter, clang -cc1 -fincremental-extensions
/// and in tools such as clang-repl.
-class TopLevelStmtDecl : public Decl {
+class TopLevelStmtDecl : public Decl, public DeclContext {
friend class ASTDeclReader;
friend class ASTDeclWriter;
@@ -4427,7 +4427,7 @@ class TopLevelStmtDecl : public Decl {
bool IsSemiMissing = false;
TopLevelStmtDecl(DeclContext *DC, SourceLocation L, Stmt *S)
- : Decl(TopLevelStmt, DC, L), Statement(S) {}
+ : Decl(TopLevelStmt, DC, L), DeclContext(TopLevelStmt), Statement(S) {}
virtual void anchor();
@@ -4438,15 +4438,19 @@ class TopLevelStmtDecl : public Decl {
SourceRange getSourceRange() const override LLVM_READONLY;
Stmt *getStmt() { return Statement; }
const Stmt *getStmt() const { return Statement; }
- void setStmt(Stmt *S) {
- assert(IsSemiMissing && "Operation supported for printing values only!");
- Statement = S;
- }
+ void setStmt(Stmt *S);
bool isSemiMissing() const { return IsSemiMissing; }
void setSemiMissing(bool Missing = true) { IsSemiMissing = Missing; }
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == TopLevelStmt; }
+
+ static DeclContext *castToDeclContext(const TopLevelStmtDecl *D) {
+ return static_cast<DeclContext *>(const_cast<TopLevelStmtDecl *>(D));
+ }
+ static TopLevelStmtDecl *castFromDeclContext(const DeclContext *DC) {
+ return static_cast<TopLevelStmtDecl *>(const_cast<DeclContext *>(DC));
+ }
};
/// Represents a block literal declaration, which is like an
diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 9a4736019d1b1b..76810a86a78a46 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -2120,6 +2120,7 @@ class DeclContext {
case Decl::Block:
case Decl::Captured:
case Decl::ObjCMethod:
+ case Decl::TopLevelStmt:
return true;
default:
return getDeclKind() >= Decl::firstFunction &&
diff --git a/clang/include/clang/Basic/DeclNodes.td b/clang/include/clang/Basic/DeclNodes.td
index 8b1f415dd5fe2c..48396e85c5adac 100644
--- a/clang/include/clang/Basic/DeclNodes.td
+++ b/clang/include/clang/Basic/DeclNodes.td
@@ -95,7 +95,7 @@ def LinkageSpec : DeclNode<Decl>, DeclContext;
def Export : DeclNode<Decl>, DeclContext;
def ObjCPropertyImpl : DeclNode<Decl>;
def FileScopeAsm : DeclNode<Decl>;
-def TopLevelStmt : DeclNode<Decl>;
+def TopLevelStmt : DeclNode<Decl>, DeclContext;
def AccessSpec : DeclNode<Decl>;
def Friend : DeclNode<Decl>;
def FriendTemplate : DeclNode<Decl>;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index ef4b93fac95ce5..db45de107163a2 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -3307,7 +3307,8 @@ class Sema final {
SourceLocation AsmLoc,
SourceLocation RParenLoc);
- Decl *ActOnTopLevelStmtDecl(Stmt *Statement);
+ TopLevelStmtDecl *ActOnStartTopLevelStmtDecl(Scope *S);
+ void ActOnFinishTopLevelStmtDecl(TopLevelStmtDecl *D, Stmt *Statement);
/// Handle a C++11 empty-declaration and attribute-declaration.
Decl *ActOnEmptyDeclaration(Scope *S, const ParsedAttributesView &AttrList,
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 5d6bb72a208a1a..5f2edee3e60a0d 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -5539,14 +5539,13 @@ FileScopeAsmDecl *FileScopeAsmDecl::CreateDeserialized(ASTContext &C,
void TopLevelStmtDecl::anchor() {}
TopLevelStmtDecl *TopLevelStmtDecl::Create(ASTContext &C, Stmt *Statement) {
- assert(Statement);
assert(C.getLangOpts().IncrementalExtensions &&
"Must be used only in incremental mode");
- SourceLocation BeginLoc = Statement->getBeginLoc();
+ SourceLocation Loc = Statement ? Statement->getBeginLoc() : SourceLocation();
DeclContext *DC = C.getTranslationUnitDecl();
- return new (C, DC) TopLevelStmtDecl(DC, BeginLoc, Statement);
+ return new (C, DC) TopLevelStmtDecl(DC, Loc, Statement);
}
TopLevelStmtDecl *TopLevelStmtDecl::CreateDeserialized(ASTContext &C,
@@ -5559,6 +5558,12 @@ SourceRange TopLevelStmtDecl::getSourceRange() const {
return SourceRange(getLocation(), Statement->getEndLoc());
}
+void TopLevelStmtDecl::setStmt(Stmt *S) {
+ assert(S);
+ Statement = S;
+ setLocation(Statement->getBeginLoc());
+}
+
void EmptyDecl::anchor() {}
EmptyDecl *EmptyDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L) {
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 10fe8bb97ce660..fcedb3cfd176a0 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1352,6 +1352,7 @@ DeclContext *DeclContext::getPrimaryContext() {
case Decl::ExternCContext:
case Decl::LinkageSpec:
case Decl::Export:
+ case Decl::TopLevelStmt:
case Decl::Block:
case Decl::Captured:
case Decl::OMPDeclareReduction:
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index edfab11c37cf0f..25634a5889271e 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -5676,24 +5676,32 @@ Parser::DeclGroupPtrTy Parser::ParseTopLevelStmtDecl() {
// Parse a top-level-stmt.
Parser::StmtVector Stmts;
ParsedStmtContext SubStmtCtx = ParsedStmtContext();
- Actions.PushFunctionScope();
+ ParseScope FnScope(this, Scope::FnScope | Scope::DeclScope |
+ Scope::CompoundStmtScope);
+ TopLevelStmtDecl *TLSD = Actions.ActOnStartTopLevelStmtDecl(getCurScope());
StmtResult R = ParseStatementOrDeclaration(Stmts, SubStmtCtx);
- Actions.PopFunctionScopeInfo();
if (!R.isUsable())
return nullptr;
- SmallVector<Decl *, 2> DeclsInGroup;
- DeclsInGroup.push_back(Actions.ActOnTopLevelStmtDecl(R.get()));
+ Actions.ActOnFinishTopLevelStmtDecl(TLSD, R.get());
if (Tok.is(tok::annot_repl_input_end) &&
Tok.getAnnotationValue() != nullptr) {
ConsumeAnnotationToken();
- cast<TopLevelStmtDecl>(DeclsInGroup.back())->setSemiMissing();
+ TLSD->setSemiMissing();
}
- // Currently happens for things like -fms-extensions and use `__if_exists`.
- for (Stmt *S : Stmts)
- DeclsInGroup.push_back(Actions.ActOnTopLevelStmtDecl(S));
+ SmallVector<Decl *, 2> DeclsInGroup;
+ DeclsInGroup.push_back(TLSD);
+
+ // Currently happens for things like -fms-extensions and use `__if_exists`.
+ for (Stmt *S : Stmts) {
+ // Here we should be safe as `__if_exists` and friends are not introducing
+ // new variables which need to live outside file scope.
+ TopLevelStmtDecl *D = Actions.ActOnStartTopLevelStmtDecl(getCurScope());
+ Actions.ActOnFinishTopLevelStmtDecl(D, S);
+ DeclsInGroup.push_back(D);
+ }
return Actions.BuildDeclaratorGroup(DeclsInGroup);
}
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9fdd8eb236d1ee..438a4b7fbe844a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -20446,12 +20446,22 @@ Decl *Sema::ActOnFileScopeAsmDecl(Expr *expr,
return New;
}
-Decl *Sema::ActOnTopLevelStmtDecl(Stmt *Statement) {
- auto *New = TopLevelStmtDecl::Create(Context, Statement);
- Context.getTranslationUnitDecl()->addDecl(New);
+TopLevelStmtDecl *Sema::ActOnStartTopLevelStmtDecl(Scope *S) {
+ auto *New = TopLevelStmtDecl::Create(Context, /*Statement=*/nullptr);
+ CurContext->addDecl(New);
+ PushDeclContext(S, New);
+ PushFunctionScope();
+ PushCompoundScope(false);
return New;
}
+void Sema::ActOnFinishTopLevelStmtDecl(TopLevelStmtDecl *D, Stmt *Statement) {
+ D->setStmt(Statement);
+ PopCompoundScope();
+ PopFunctionScopeInfo();
+ PopDeclContext();
+}
+
void Sema::ActOnPragmaRedefineExtname(IdentifierInfo* Name,
IdentifierInfo* AliasName,
SourceLocation PragmaLoc,
diff --git a/clang/test/Interpreter/execute-stmts.cpp b/clang/test/Interpreter/execute-stmts.cpp
index 2d4c17e0c91e66..e341b06d154f18 100644
--- a/clang/test/Interpreter/execute-stmts.cpp
+++ b/clang/test/Interpreter/execute-stmts.cpp
@@ -9,7 +9,6 @@
//CODEGEN-CHECK-COUNT-2: define internal void @__stmts__
//CODEGEN-CHECK-NOT: define internal void @__stmts__
-
extern "C" int printf(const char*,...);
template <typename T> T call() { printf("called\n"); return T(); }
@@ -41,3 +40,16 @@ for (; i > 4; --i) { printf("i = %d\n", i); };
int j = i; printf("j = %d\n", j);
// CHECK-NEXT: j = 4
+
+if (int i = j) printf("i = %d\n", i);
+// CHECK-NEXT: i = 4
+
+for (int i = j; i > 3; --i) printf("i = %d\n", i);
+// CHECK-NEXT: i = 4
+
+for(int i=0; i<2; i+=1) {};
+
+for(int i=0; i<2; i+=1) ;
+
+int *aa=nullptr;
+if (auto *b=aa) *b += 1;
``````````
</details>
https://github.com/llvm/llvm-project/pull/84150
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