riccibruno created this revision.
riccibruno added reviewers: vabridgers, martong, aaron.ballman.
riccibruno added a project: clang.
Herald added subscribers: cfe-commits, rnkovacs.
05843dc6ab97a00cbde7aa4f08bf3692eb83109d
<https://reviews.llvm.org/rG05843dc6ab97a00cbde7aa4f08bf3692eb83109d> changed
the serialization of the body
of `LambdaExpr` to avoid a mutation in `LambdaExpr::getBody` and to avoid a
missing
body in `LambdaExpr::children`.
Unfortunately this replaced one bug by another: we are now duplicating the body
during
deserialization; that is after deserialization the identity:
`E->getBody() == E->getCallOperator()->getBody()` does not hold.
Fix that by instead lazily loading the body from the call operator when needed.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D83009
Files:
clang/include/clang/AST/ExprCXX.h
clang/lib/AST/ExprCXX.cpp
clang/lib/Serialization/ASTReaderStmt.cpp
clang/lib/Serialization/ASTWriterStmt.cpp
clang/test/AST/ast-dump-lambda-body-not-duplicated.cpp
Index: clang/test/AST/ast-dump-lambda-body-not-duplicated.cpp
===================================================================
--- /dev/null
+++ clang/test/AST/ast-dump-lambda-body-not-duplicated.cpp
@@ -0,0 +1,26 @@
+// Test without serialization:
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -Wno-unused-value -ast-dump %s \
+// RUN: | FileCheck %s
+//
+// Test with serialization:
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -Wno-unused-value -emit-pch -o %t %s
+// RUN: %clang_cc1 -x c++ -triple x86_64-unknown-unknown -Wno-unused-value \
+// RUN: -include-pch %t -ast-dump-all /dev/null \
+// RUN: | FileCheck %s
+
+// Make sure that the Stmt * for the body of the LambdaExpr is
+// equal to the Stmt * for the body of the call operator.
+void Test() {
+ []() {
+ return 42;
+ };
+}
+
+// CHECK: FunctionDecl {{.*}} Test
+//
+// CHECK: CXXMethodDecl {{.*}} operator() 'int () const' inline
+// CHECK-NEXT: CompoundStmt 0x[[TMP:.*]]
+// CHECK: IntegerLiteral {{.*}} 'int' 42
+//
+// CHECK: CompoundStmt 0x[[TMP]]
+// Check: IntegerLiteral {{.*}} 'int' 42
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1615,7 +1615,8 @@
Record.AddStmt(*C);
}
- Record.AddStmt(E->getBody());
+ // Don't serialize the body. It belongs to the call operator declaration.
+ // LambdaExpr only stores a copy of the Stmt *.
Code = serialization::EXPR_LAMBDA;
}
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1715,12 +1715,12 @@
// Read capture initializers.
for (LambdaExpr::capture_init_iterator C = E->capture_init_begin(),
- CEnd = E->capture_init_end();
+ CEnd = E->capture_init_end();
C != CEnd; ++C)
*C = Record.readSubExpr();
- // Ok, not one past the end.
- E->getStoredStmts()[NumCaptures] = Record.readSubStmt();
+ // The body will be lazily deserialized when needed from the call operator
+ // declaration.
}
void
Index: clang/lib/AST/ExprCXX.cpp
===================================================================
--- clang/lib/AST/ExprCXX.cpp
+++ clang/lib/AST/ExprCXX.cpp
@@ -1118,6 +1118,10 @@
LambdaExpr::LambdaExpr(EmptyShell Empty, unsigned NumCaptures)
: Expr(LambdaExprClass, Empty) {
LambdaExprBits.NumCaptures = NumCaptures;
+
+ // Initially don't initialize the body of the LambdaExpr. The body will
+ // be lazily deserialized when needed.
+ getStoredStmts()[NumCaptures] = nullptr; // Not one past the end.
}
LambdaExpr *LambdaExpr::Create(const ASTContext &Context, CXXRecordDecl *Class,
@@ -1147,6 +1151,25 @@
return new (Mem) LambdaExpr(EmptyShell(), NumCaptures);
}
+void LambdaExpr::initBodyIfNeeded() const {
+ if (!getStoredStmts()[capture_size()]) {
+ auto *This = const_cast<LambdaExpr *>(this);
+ This->getStoredStmts()[capture_size()] = getCallOperator()->getBody();
+ }
+}
+
+Stmt *LambdaExpr::getBody() const {
+ initBodyIfNeeded();
+ return getStoredStmts()[capture_size()];
+}
+
+const CompoundStmt *LambdaExpr::getCompoundStmtBody() const {
+ Stmt *Body = getBody();
+ if (const auto *CoroBody = dyn_cast<CoroutineBodyStmt>(Body))
+ return cast<CompoundStmt>(CoroBody->getBody());
+ return cast<CompoundStmt>(Body);
+}
+
bool LambdaExpr::isInitCapture(const LambdaCapture *C) const {
return (C->capturesVariable() && C->getCapturedVar()->isInitCapture() &&
(getCallOperator() == C->getCapturedVar()->getDeclContext()));
@@ -1216,6 +1239,17 @@
bool LambdaExpr::isMutable() const { return !getCallOperator()->isConst(); }
+LambdaExpr::child_range LambdaExpr::children() {
+ initBodyIfNeeded();
+ return child_range(getStoredStmts(), getStoredStmts() + capture_size() + 1);
+}
+
+LambdaExpr::const_child_range LambdaExpr::children() const {
+ initBodyIfNeeded();
+ return const_child_range(getStoredStmts(),
+ getStoredStmts() + capture_size() + 1);
+}
+
ExprWithCleanups::ExprWithCleanups(Expr *subexpr,
bool CleanupsHaveSideEffects,
ArrayRef<CleanupObject> objects)
Index: clang/include/clang/AST/ExprCXX.h
===================================================================
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -1861,6 +1861,8 @@
Stmt **getStoredStmts() { return getTrailingObjects<Stmt *>(); }
Stmt *const *getStoredStmts() const { return getTrailingObjects<Stmt *>(); }
+ void initBodyIfNeeded() const;
+
public:
friend class ASTStmtReader;
friend class ASTStmtWriter;
@@ -2009,17 +2011,12 @@
/// a \p CompoundStmt, but can also be \p CoroutineBodyStmt wrapping
/// a \p CompoundStmt. Note that unlike functions, lambda-expressions
/// cannot have a function-try-block.
- Stmt *getBody() const { return getStoredStmts()[capture_size()]; }
+ Stmt *getBody() const;
/// Retrieve the \p CompoundStmt representing the body of the lambda.
/// This is a convenience function for callers who do not need
/// to handle node(s) which may wrap a \p CompoundStmt.
- const CompoundStmt *getCompoundStmtBody() const {
- Stmt *Body = getBody();
- if (const auto *CoroBody = dyn_cast<CoroutineBodyStmt>(Body))
- return cast<CompoundStmt>(CoroBody->getBody());
- return cast<CompoundStmt>(Body);
- }
+ const CompoundStmt *getCompoundStmtBody() const;
CompoundStmt *getCompoundStmtBody() {
const auto *ConstThis = this;
return const_cast<CompoundStmt *>(ConstThis->getCompoundStmtBody());
@@ -2048,15 +2045,9 @@
SourceLocation getEndLoc() const LLVM_READONLY { return ClosingBrace; }
- child_range children() {
- // Includes initialization exprs plus body stmt
- return child_range(getStoredStmts(), getStoredStmts() + capture_size() + 1);
- }
-
- const_child_range children() const {
- return const_child_range(getStoredStmts(),
- getStoredStmts() + capture_size() + 1);
- }
+ /// Includes the captures and the body of the lambda.
+ child_range children();
+ const_child_range children() const;
};
/// An expression "T()" which creates a value-initialized rvalue of type
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