[Sema] Make getCurFunction() return null outside function parsing

Summary:
Before this patch, Sema pre-allocated a FunctionScopeInfo and kept it in
the first, always present element of the FunctionScopes stack. This
meant that Sema::getCurFunction would return a pointer to this
pre-allocated object when parsing code outside a function body. This is
pretty much always a bug, so this patch moves the pre-allocated object
into a separate unique_ptr. This should make bugs like PR36536 a lot
more obvious.

As you can see from this patch, there were a number of places that
unconditionally assumed they were always called inside a function.
However, there are also many places that null checked the result of
getCurFunction(), so I think this is a reasonable direction.

Reviewers: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D44039

llvm-svn: 326965

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 95b56a242a6..07eb02bec06 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -13126,7 +13126,7 @@ ExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
     for (const auto &CI : Result->getBlockDecl()->captures()) {
       const VarDecl *var = CI.getVariable();
       if (var->getType().isDestructedType() != QualType::DK_none) {
-        getCurFunction()->setHasBranchProtectedScope();
+        setFunctionHasBranchProtectedScope();
         break;
       }
     }