[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/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index fc1cc7bbe54..cad398a13d9 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -793,7 +793,7 @@ StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                                 ArrayRef<Expr*> Exprs,
                                 SourceLocation EndLoc) {
   bool IsSimple = (NumOutputs != 0 || NumInputs != 0);
-  getCurFunction()->setHasBranchProtectedScope();
+  setFunctionHasBranchProtectedScope();
   MSAsmStmt *NS =
     new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
                             /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,