Richard, yes, I understood that. We have troubles in CodeGen in this
case. Yes, I can call getSizeExpr() for VariableArrayType, by it is
impossible to get llvm::Value* for the expression returned by
getSizeExpr() in lambda operator(). This value is calculated in parent
function for lambda expr and we have to pass it somehow to lambda.
Passing VariableArrayType* does not allow us to get an access to this
value.
We must not recalculate the value of expression from getSizeExpr(), we
must use the value, calculated in parent function. That's why it is not
enough just to pass VariableArrayType*, also we need to pass
llvm::Value* for getSizeExpr(), calculated in parent function.
Best regards,
Alexey Bataev
=============
Software Engineer
Intel Compiler Team
22 Июль 2014 г. 9:41:43, Richard Smith писал:
On Mon, Jul 21, 2014 at 10:14 PM, Bataev, Alexey <[email protected]
<mailto:[email protected]>> wrote:
Richard, I don't think this is possible. If we storing
VariableLengthArray* on FieldDecl, then in Lambda operator we can
access VariableLengthArray->__getSizeExpr(). But! We won't be able
to get the llvm::Value* for this
VariableLengthArray->__getSizeExpr(), calculated in another
function. We should pass this llvm::Value* as a member of
RecordDecl for LambdaExpr! Here is a scheme:
foo() {
int vla[n+m];
....
some_lambda {vla....;}
....
}
What we have in CodeGen for this example:
CodeGenFunction(foo), llvm::DenseMap<const Expr*, llvm::Value*>
VLASizeMap[n+m]=value; VLASizeMap stores pre-calculated size of
each VLA.
{
FD->field_for_m+n_expr = (int [n+m]*)0;
CodeGenFunction CGF(some_lambda.operator(), FD);
}
CodeGenFunction(some_lambda.__operator()), llvm::DenseMap<const
Expr*, llvm::Value*> VLASizeMap[n+m]=????? - llvm::Value* for
'n+m' is not captured here, we don't have an access to 'value',
calculated in CodeGenFunction(foo) for expression 'n+m'.
To solve this problem we can try to capture 2 fields instead - one
for VariableLengthArray*, and another one for llvm::Value*
calculated for VariableLengthArray->__getSizeExpr().
I'm sorry, I still think we're miscommunicating. What I'm suggesting
is a mechanical transformation: store the VariableArrayType* on the
FieldDecl, and then when you need the size expression that you're
currently storing there, call getSizeExpr() on the type.
Best regards,
Alexey Bataev
=============
Software Engineer
Intel Compiler Team
22 Июль 2014 г. 8:57:54, Richard Smith писал:
On Mon, Jul 21, 2014 at 5:43 AM, Alexey Bataev
<[email protected] <mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>>
wrote:
Updated version after last review. Unfortunately, I don't
think it
is possible to pass captured expression as a
VariableLengthArray
*. I have to capture expr of VariableLengthArray * and
then cast
it to SizeExpr->getType() type to make lambda capture this
type,
not VariableLengthArray *. I have to pass actual value of
SizeExpr
to the Lambda in this field, because it is defined only in
calling
function and in Lambda it can be received only in one of
captured
fields.
I don't understand what you're saying. What I'm suggesting is
storing
the VariableLengthArray* in the InitializerOrBitWidth field on
FieldDecl, instead of storing the array bound there.
http://reviews.llvm.org/D4368
Files:
include/clang/AST/Decl.h
include/clang/AST/__LambdaCapture.h
include/clang/Basic/__DiagnosticSemaKinds.td
lib/AST/Decl.cpp
lib/AST/Expr.cpp
lib/AST/ExprCXX.cpp
lib/AST/StmtPrinter.cpp
lib/AST/StmtProfile.cpp
lib/CodeGen/CGDebugInfo.cpp
lib/CodeGen/CGExprCXX.cpp
lib/CodeGen/CodeGenFunction.__cpp
lib/Sema/SemaDecl.cpp
lib/Sema/SemaExpr.cpp
lib/Sema/TreeTransform.h
test/CodeGenCXX/instantiate-__typeof-vla.cpp
test/SemaTemplate/instantiate-__typeof.cpp
tools/libclang/IndexBody.cpp
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