vabridgers added inline comments.
================
Comment at:
clang/include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h:378
+ type = type->isReferenceType()
+ ? Context.getPointerType(type->getPointeeType())
+ : type;
----------------
NoQ wrote:
> vabridgers wrote:
> > NoQ wrote:
> > > How do you discover the pointer width by looking only at the pointee
> > > type? Are objects of specific type always restricted to a specific
> > > address space? I.e., does every `int *` have the same width everywhere in
> > > the program? If not, how is this code supposed to work?
> > The case this code addresses is represented in the test case
> > clang/test/Analysis/cast-value-notes.cpp, this function ...
> >
> > ```
> > 24 void evalReferences(const Shape &S) {
> > 25 const auto &C = dyn_cast<Circle>(S);
> > 26 // expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
> > 27 // expected-note@-2 {{Dereference of null pointer}}
> > 28 // expected-warning@-3 {{Dereference of null pointer}}
> > 29 }
> >
> > ```
> > The crash occurs from line 25 above.
> >
> > Debug printing what I see at this point in the code for this case ...
> >
> > ```
> > QualType type : LValueReferenceType 0xffea820 'const class clang::Circle &'
> > `-QualType 0xffea7c1 'const class clang::Circle' const
> > `-SubstTemplateTypeParmType 0xffea7c0 'class clang::Circle' sugar
> > |-TemplateTypeParmType 0xffe4f90 'X' dependent depth 0 index 0
> > | `-TemplateTypeParm 0xffe4f40 'X'
> > `-RecordType 0xffea090 'class clang::Circle'
> > `-CXXRecord 0xffea000 'Circle'
> >
> > Context.getPointerType(type) : PointerType 0x10006ab0 'const class
> > clang::Circle &*'
> > `-LValueReferenceType 0xffea820 'const class clang::Circle &'
> > `-QualType 0xffea7c1 'const class clang::Circle' const
> > `-SubstTemplateTypeParmType 0xffea7c0 'class clang::Circle' sugar
> > |-TemplateTypeParmType 0xffe4f90 'X' dependent depth 0 index 0
> > | `-TemplateTypeParm 0xffe4f40 'X'
> > `-RecordType 0xffea090 'class clang::Circle'
> > `-CXXRecord 0xffea000 'Circle'
> >
> > Context.getPointerType(type->getPointeeType()) : PointerType 0x10006ae0
> > 'const class clang::Circle *'
> > `-QualType 0xffea7c1 'const class clang::Circle' const
> > `-SubstTemplateTypeParmType 0xffea7c0 'class clang::Circle' sugar
> > |-TemplateTypeParmType 0xffe4f90 'X' dependent depth 0 index 0
> > | `-TemplateTypeParm 0xffe4f40 'X'
> > `-RecordType 0xffea090 'class clang::Circle'
> > `-CXXRecord 0xffea000 'Circle'
> >
> > ```
> > The LValueReferenceType causes a crash if I do not get a pointer type,
> > looks like ...
> >
> > ```
> > clang:
> > <root>/clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h:219:
> > const llvm::APSInt&
> > clang::ento::BasicValueFactory::getZeroWithTypeSize(clang::QualType):
> > Assertion `T->isScalarType()' failed.
> >
> > ```
> > I'm assuming the pointer type retains the address space attribute of the
> > LValueReferenceType.
> >
> > Context.getPointerType(type->getPointeeType()) produces a QualType :
> > PointerType 'const class clang::Circle *' from an original QualType :
> > LValueReferenceType 'const class clang::Circle &'
> >
> > Is this not what's wanted - a pointer type instead of a reference, with the
> > same address space qualifiers, or am I missing something in the query?
> >
> > Thanks
> Do I understand correctly that `__attribute__((address_space))` is a type
> attribute that gets applied to values rather than to pointers, so
> `__attribute__((address_space(3))) int *x` defines `x` as "pointer to (int
> that lives in address_space(3))", so when you unwrap the pointer type you get
> an "int that lives in address_space(3)"?
>
> Can you share some dumps to demonstrate that the attribute is correctly
> preserved by this procedure? Damn, a test case could be great if we could
> have them.
I'll see what can be done about a test case, and provide the dumps for
evaluation. Best
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D119601/new/
https://reviews.llvm.org/D119601
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