Re: r301735 - Fix PR32831: 'this capture while instantiating generic lambda call operator specialization
I'll revert this as it makes the following snippet makes clang crash:
class SomeClass {
public:
void foo() {
auto l = [this] { auto l = [] EXCLUSIVE_LOCKS_REQUIRED(mu_) {}; };
}
Mutex mu_;
};
(e.g. this can be added to test/SemaCXX/warn-thread-safety-parsing.cpp)
>From a brief look at the backtrace, it seems like
CurLSI->Lambda->getDeclContext() fails.
On Fri, Apr 28, 2017 at 8:49 PM, Faisal Vali via cfe-commits <
cfe-commits@lists.llvm.org> wrote:
> Author: faisalv
> Date: Fri Apr 28 22:49:17 2017
> New Revision: 301735
>
> URL: http://llvm.org/viewvc/llvm-project?rev=301735&view=rev
> Log:
> Fix PR32831: 'this capture while instantiating generic lambda call
> operator specialization
>
> When computing the appropriate cv-qualifiers for the 'this' capture, we
> have to examine each enclosing lambda - but when using the
> FunctionScopeInfo stack we have to ensure that the lambda below (outer) is
> the decl-context of the closure-class of the current lambda.
>
> https://bugs.llvm.org/show_bug.cgi?id=32831
>
> Modified:
> cfe/trunk/lib/Sema/SemaExprCXX.cpp
> cfe/trunk/test/SemaCXX/cxx1z-lambda-star-this.cpp
>
> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/
> SemaExprCXX.cpp?rev=301735&r1=301734&r2=301735&view=diff
>
> ==
> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Fri Apr 28 22:49:17 2017
> @@ -901,17 +901,35 @@ static QualType adjustCVQualifiersForCXX
>// capturing lamdbda's call operator.
>//
>
> - // The issue is that we cannot rely entirely on the FunctionScopeInfo
> stack
> - // since ScopeInfos are pushed on during parsing and treetransforming.
> But
> - // since a generic lambda's call operator can be instantiated anywhere
> (even
> - // end of the TU) we need to be able to examine its enclosing lambdas
> and so
> - // we use the DeclContext to get a hold of the closure-class and query
> it for
> - // capture information. The reason we don't just resort to always
> using the
> - // DeclContext chain is that it is only mature for lambda expressions
> - // enclosing generic lambda's call operators that are being
> instantiated.
> + // Since the FunctionScopeInfo stack is representative of the lexical
> + // nesting of the lambda expressions during initial parsing (and is the
> best
> + // place for querying information about captures about lambdas that are
> + // partially processed) and perhaps during instantiation of function
> templates
> + // that contain lambda expressions that need to be transformed BUT not
> + // necessarily during instantiation of a nested generic lambda's
> function call
> + // operator (which might even be instantiated at the end of the TU) -
> at which
> + // time the DeclContext tree is mature enough to query capture
> information
> + // reliably - we use a two pronged approach to walk through all the
> lexically
> + // enclosing lambda expressions:
> + //
> + // 1) Climb down the FunctionScopeInfo stack as long as each item
> represents
> + // a Lambda (i.e. LambdaScopeInfo) AND each LSI's 'closure-type' is
> lexically
> + // enclosed by the call-operator of the LSI below it on the stack
> (while
> + // tracking the enclosing DC for step 2 if needed). Note the topmost
> LSI on
> + // the stack represents the innermost lambda.
> + //
> + // 2) Iterate out through the DeclContext chain (if it represents a
> lambda's
> + // call operator, and therefore must be a generic lambda's call
> operator,
> + // which is the only time an inconsistency between the LSI and the
> + // DeclContext should occur) querying closure types regarding capture
> + // information.
>
> +
> + // 1) Climb down the function scope info stack.
>for (int I = FunctionScopes.size();
> - I-- && isa(FunctionScopes[I]);
> + I-- && isa(FunctionScopes[I]) &&
> + (!CurLSI || CurLSI->Lambda->getDeclContext() ==
> + cast(FunctionScopes[I])->
> CallOperator);
> CurDC = getLambdaAwareParentOfDeclContext(CurDC)) {
> CurLSI = cast(FunctionScopes[I]);
>
> @@ -927,11 +945,17 @@ static QualType adjustCVQualifiersForCXX
>return ASTCtx.getPointerType(ClassType);
> }
>}
> - // We've run out of ScopeInfos but check if CurDC is a lambda (which can
> - // happen during instantiation of generic lambdas)
> +
> + // 2) We've run out of ScopeInfos but check if CurDC is a lambda (which
> can
> + // happen during instantiation of its nested generic lambda call
> operator)
>if (isLambdaCallOperator(CurDC)) {
> -assert(CurLSI);
> -assert(isGenericLambdaCallOperatorSpecialization(CurLSI->
> CallOperator));
> +assert(CurLSI && "While computing 'this' capture-type for a generic "
> + "lambda, we must have a corresponding
> LambdaScopeInfo");
> +assert(isGenericLambdaCa
r301735 - Fix PR32831: 'this capture while instantiating generic lambda call operator specialization
Author: faisalv
Date: Fri Apr 28 22:49:17 2017
New Revision: 301735
URL: http://llvm.org/viewvc/llvm-project?rev=301735&view=rev
Log:
Fix PR32831: 'this capture while instantiating generic lambda call operator
specialization
When computing the appropriate cv-qualifiers for the 'this' capture, we have to
examine each enclosing lambda - but when using the FunctionScopeInfo stack we
have to ensure that the lambda below (outer) is the decl-context of the
closure-class of the current lambda.
https://bugs.llvm.org/show_bug.cgi?id=32831
Modified:
cfe/trunk/lib/Sema/SemaExprCXX.cpp
cfe/trunk/test/SemaCXX/cxx1z-lambda-star-this.cpp
Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=301735&r1=301734&r2=301735&view=diff
==
--- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Fri Apr 28 22:49:17 2017
@@ -901,17 +901,35 @@ static QualType adjustCVQualifiersForCXX
// capturing lamdbda's call operator.
//
- // The issue is that we cannot rely entirely on the FunctionScopeInfo stack
- // since ScopeInfos are pushed on during parsing and treetransforming. But
- // since a generic lambda's call operator can be instantiated anywhere (even
- // end of the TU) we need to be able to examine its enclosing lambdas and so
- // we use the DeclContext to get a hold of the closure-class and query it for
- // capture information. The reason we don't just resort to always using the
- // DeclContext chain is that it is only mature for lambda expressions
- // enclosing generic lambda's call operators that are being instantiated.
+ // Since the FunctionScopeInfo stack is representative of the lexical
+ // nesting of the lambda expressions during initial parsing (and is the best
+ // place for querying information about captures about lambdas that are
+ // partially processed) and perhaps during instantiation of function
templates
+ // that contain lambda expressions that need to be transformed BUT not
+ // necessarily during instantiation of a nested generic lambda's function
call
+ // operator (which might even be instantiated at the end of the TU) - at
which
+ // time the DeclContext tree is mature enough to query capture information
+ // reliably - we use a two pronged approach to walk through all the lexically
+ // enclosing lambda expressions:
+ //
+ // 1) Climb down the FunctionScopeInfo stack as long as each item represents
+ // a Lambda (i.e. LambdaScopeInfo) AND each LSI's 'closure-type' is
lexically
+ // enclosed by the call-operator of the LSI below it on the stack (while
+ // tracking the enclosing DC for step 2 if needed). Note the topmost LSI on
+ // the stack represents the innermost lambda.
+ //
+ // 2) Iterate out through the DeclContext chain (if it represents a lambda's
+ // call operator, and therefore must be a generic lambda's call operator,
+ // which is the only time an inconsistency between the LSI and the
+ // DeclContext should occur) querying closure types regarding capture
+ // information.
+
+ // 1) Climb down the function scope info stack.
for (int I = FunctionScopes.size();
- I-- && isa(FunctionScopes[I]);
+ I-- && isa(FunctionScopes[I]) &&
+ (!CurLSI || CurLSI->Lambda->getDeclContext() ==
+ cast(FunctionScopes[I])->CallOperator);
CurDC = getLambdaAwareParentOfDeclContext(CurDC)) {
CurLSI = cast(FunctionScopes[I]);
@@ -927,11 +945,17 @@ static QualType adjustCVQualifiersForCXX
return ASTCtx.getPointerType(ClassType);
}
}
- // We've run out of ScopeInfos but check if CurDC is a lambda (which can
- // happen during instantiation of generic lambdas)
+
+ // 2) We've run out of ScopeInfos but check if CurDC is a lambda (which can
+ // happen during instantiation of its nested generic lambda call operator)
if (isLambdaCallOperator(CurDC)) {
-assert(CurLSI);
-assert(isGenericLambdaCallOperatorSpecialization(CurLSI->CallOperator));
+assert(CurLSI && "While computing 'this' capture-type for a generic "
+ "lambda, we must have a corresponding LambdaScopeInfo");
+assert(isGenericLambdaCallOperatorSpecialization(CurLSI->CallOperator) &&
+ "While computing 'this' capture-type for a generic lambda, when we "
+ "run out of enclosing LSI's, yet the enclosing DC is a "
+ "lambda-call-operator we must be (i.e. Current LSI) in a generic "
+ "lambda call oeprator");
assert(CurDC == getLambdaAwareParentOfDeclContext(CurLSI->CallOperator));
auto IsThisCaptured =
Modified: cfe/trunk/test/SemaCXX/cxx1z-lambda-star-this.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-lambda-star-this.cpp?rev=301735&r1=301734&r2=301735&view=diff
