vsk updated this revision to Diff 161536.
vsk added a comment.
- Here is a GIF that might help illustrate the bug:
http://net.vedantk.com/static/llvm/lambda-implicit-capture-bug.gif
- Update test/SemaCXX/uninitialized.cpp to highlight the behavior change which
comes from using getBeginOrDeclLoc().
https://reviews.llvm.org/D50927
Files:
clang/include/clang/AST/Expr.h
clang/lib/AST/Expr.cpp
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaLambda.cpp
clang/test/CodeGenCXX/debug-info-lambda.cpp
clang/test/SemaCXX/uninitialized.cpp
clang/unittests/Tooling/RecursiveASTVisitorTests/DeclRefExpr.cpp
Index: clang/unittests/Tooling/RecursiveASTVisitorTests/DeclRefExpr.cpp
===================================================================
--- clang/unittests/Tooling/RecursiveASTVisitorTests/DeclRefExpr.cpp
+++ clang/unittests/Tooling/RecursiveASTVisitorTests/DeclRefExpr.cpp
@@ -75,11 +75,14 @@
TEST(RecursiveASTVisitor, VisitsImplicitLambdaCaptureInit) {
DeclRefExprVisitor Visitor;
Visitor.setShouldVisitImplicitCode(true);
- // We're expecting the "i" in the lambda to be visited twice:
- // - Once for the DeclRefExpr in the lambda capture initialization (whose
- // source code location is set to the first use of the variable).
- // - Once for the DeclRefExpr for the use of "i" inside the lambda.
- Visitor.ExpectMatch("i", 1, 24, /*Times=*/2);
+ // We're expecting the "i" in the lambda to be visited just once (for the
+ // DeclRefExpr for the use of "i" inside the lambda).
+ //
+ // Previously, the DeclRefExpr in the implicit lambda capture initialization
+ // (whose source code location is set to the first use of the variable) was
+ // also matched. This behavior was removed because it resulted in poor debug
+ // info.
+ Visitor.ExpectMatch("i", 1, 24, /*Times=*/1);
EXPECT_TRUE(Visitor.runOver(
"void f() { int i; [=]{ i; }; }",
DeclRefExprVisitor::Lang_CXX11));
Index: clang/test/SemaCXX/uninitialized.cpp
===================================================================
--- clang/test/SemaCXX/uninitialized.cpp
+++ clang/test/SemaCXX/uninitialized.cpp
@@ -884,8 +884,10 @@
int x;
};
A a0([] { return a0.x; }); // ok
- void f() {
- A a1([=] { return a1.x; }); // expected-warning{{variable 'a1' is uninitialized when used within its own initialization}}
+ void f() {
+ A a1([=] { // expected-warning{{variable 'a1' is uninitialized when used within its own initialization}}
+ return a1.x;
+ });
A a2([&] { return a2.x; }); // ok
}
}
Index: clang/test/CodeGenCXX/debug-info-lambda.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/debug-info-lambda.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm \
+// RUN: -debug-info-kind=line-tables-only -std=c++11 %s -o - | FileCheck %s
+
+// CHECK-LABEL: define{{.*}}lambda_in_func
+void lambda_in_func(int &ref) {
+ // CHECK: [[ref_slot:%.*]] = getelementptr inbounds %class.anon, %class.anon* {{.*}}, i32 0, i32 0, !dbg [[lambda_decl_loc:![0-9]+]]
+ // CHECK-NEXT: %1 = load i32*, i32** %ref.addr, align 8, !dbg [[init_sequence_loc:![0-9]+]]
+ // CHECK-NEXT: store i32* %1, i32** %0, align 8, !dbg [[lambda_decl_loc]]
+ // CHECK-NEXT: call void {{.*}}, !dbg [[lambda_call_loc:![0-9]+]]
+
+ auto helper = [&]() { // CHECK: [[lambda_decl_loc]] = !DILocation(line: [[@LINE]]
+ ++ref; // CHECK: [[init_sequence_loc]] = !DILocation(line: 0
+ };
+ helper(); // CHECK: [[lambda_call_loc]] = !DILocation(line: [[@LINE]]
+}
Index: clang/lib/Sema/SemaLambda.cpp
===================================================================
--- clang/lib/Sema/SemaLambda.cpp
+++ clang/lib/Sema/SemaLambda.cpp
@@ -1392,13 +1392,13 @@
Class->addDecl(Conversion);
}
-static ExprResult performLambdaVarCaptureInitialization(Sema &S,
- const Capture &Capture,
- FieldDecl *Field) {
+static ExprResult performLambdaVarCaptureInitialization(
+ Sema &S, const Capture &Capture, FieldDecl *Field, bool IsImplicitCapture) {
assert(Capture.isVariableCapture() && "not a variable capture");
auto *Var = Capture.getVariable();
SourceLocation Loc = Capture.getLocation();
+ SourceLocation InitLoc = IsImplicitCapture ? SourceLocation() : Loc;
// C++11 [expr.prim.lambda]p21:
// When the lambda-expression is evaluated, the entities that
@@ -1413,7 +1413,7 @@
// An entity captured by a lambda-expression is odr-used (3.2) in
// the scope containing the lambda-expression.
ExprResult RefResult = S.BuildDeclarationNameExpr(
- CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), Loc), Var);
+ CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), InitLoc), Var);
if (RefResult.isInvalid())
return ExprError();
Expr *Ref = RefResult.get();
@@ -1607,8 +1607,8 @@
Var, From.getEllipsisLoc()));
Expr *Init = From.getInitExpr();
if (!Init) {
- auto InitResult =
- performLambdaVarCaptureInitialization(*this, From, *CurField);
+ auto InitResult = performLambdaVarCaptureInitialization(
+ *this, From, *CurField, IsImplicit);
if (InitResult.isInvalid())
return ExprError();
Init = InitResult.get();
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -10686,7 +10686,7 @@
return;
}
- S.DiagRuntimeBehavior(DRE->getBeginLoc(), DRE,
+ S.DiagRuntimeBehavior(DRE->getBeginOrDeclLoc(), DRE,
S.PDiag(diag)
<< DRE->getDecl() << OrigDecl->getLocation()
<< DRE->getSourceRange());
Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -457,6 +457,12 @@
return getRAngleLoc();
return getNameInfo().getEndLoc();
}
+SourceLocation DeclRefExpr::getBeginOrDeclLoc() const {
+ SourceLocation BeginLoc = getBeginLoc();
+ if (BeginLoc.isValid())
+ return BeginLoc;
+ return getDecl()->getLocation();
+}
PredefinedExpr::PredefinedExpr(SourceLocation L, QualType FNTy, IdentType IT,
StringLiteral *SL)
Index: clang/include/clang/AST/Expr.h
===================================================================
--- clang/include/clang/AST/Expr.h
+++ clang/include/clang/AST/Expr.h
@@ -1083,6 +1083,11 @@
}
SourceLocation getEndLoc() const LLVM_READONLY;
+ /// If this declaration reference explicitly appears in the source, return
+ /// its location. Otherwise, return the location of the declaration it refers
+ /// to.
+ SourceLocation getBeginOrDeclLoc() const LLVM_READONLY;
+
/// Determine whether this declaration reference was preceded by a
/// C++ nested-name-specifier, e.g., \c N::foo.
bool hasQualifier() const { return DeclRefExprBits.HasQualifier; }
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