================
@@ -878,6 +878,65 @@ void FactsGenerator::handleImplicitObjectFieldUses(const
Expr *Call,
});
}
+void FactsGenerator::handleLifetimeCaptureBy(const FunctionDecl *FD,
+ ArrayRef<const Expr *> Args) {
+ if (Args.empty())
+ return;
+ // FIXME: Add support for capture_by on constructors.
+ if (isa<CXXConstructorDecl>(FD))
+ return;
+ const auto *Method = dyn_cast<CXXMethodDecl>(FD);
+ bool IsInstance =
+ Method && Method->isInstance() && !isa<CXXConstructorDecl>(FD);
+ auto getArgCaptureBy = [FD,
+ IsInstance](unsigned I) -> LifetimeCaptureByAttr * {
+ const ParmVarDecl *PVD = nullptr;
+ if (IsInstance) {
+ // FIXME: Add support for I == 0 i.e. capture_by on function declarations
+ if (I > 0 && I - 1 < FD->getNumParams())
+ PVD = FD->getParamDecl(I - 1);
+ } else {
+ if (I < FD->getNumParams())
+ PVD = FD->getParamDecl(I);
+ }
+ return PVD ? PVD->getAttr<LifetimeCaptureByAttr>() : nullptr;
+ };
+ for (unsigned I = 0; I < Args.size(); ++I) {
+ const LifetimeCaptureByAttr *Attr = getArgCaptureBy(I);
+ if (!Attr)
+ continue;
+ OriginList *CapturedOriginList = getOriginsList(*Args[I]);
+ if (!CapturedOriginList)
+ continue;
+ if (isGslPointerType(Args[I]->getType())) {
+ assert(!Args[I]->isGLValue() || CapturedOriginList->getLength() >= 2);
+ CapturedOriginList = getRValueOrigins(Args[I], CapturedOriginList);
+ }
----------------
usx95 wrote:
This would benefit from a comment. Can you also give examples you are targeting
here.
I am confused how is this working for this example:
```cpp
void setCaptureBy(View& res, View in [[clang::lifetime_capture_by(res)]]);
void transitive_capture() {
View v1, v2;
{
MyObj local;
v1 = local;
setCaptureBy(v2, v1);
}
(void)v2;
}
```
The captured argument expression is already a rvalue. Why would be need to have
another RValueOrigins
```
`-CXXConstructExpr <col:26> 'View' 'void (const View &) noexcept'
| `-ImplicitCastExpr <col:26> 'const View' lvalue <NoOp>
| `-DeclRefExpr <col:26> 'View' lvalue Var 0x3f280150 'v1' 'View'
```
Can you also test what happens when the `gsl::Pointer` is accepted as a ref ?
```cpp
struct [[gsl::Pointer]] OtherView {};
void foo(OtherView& res,
View& view_ref [[capture_by(res)]])) {}
```
https://github.com/llvm/llvm-project/pull/196884
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