ms-inline-asm: Scope inline asm labels to functions

Summary:
This fixes PR20023.  In order to implement this scoping rule, we piggy
back on the existing LabelDecl machinery, by creating LabelDecl's that
will carry the "internal" name of the inline assembly label, which we
will rewrite the asm label to.

Reviewers: rnk

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4589

llvm-svn: 218230

1 files changed, 30 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index 5aa1a2c86a9..dc50e87b589 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -15,6 +15,7 @@
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Scope.h"
@@ -520,6 +521,7 @@ StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                                 ArrayRef<Expr*> Exprs,
                                 SourceLocation EndLoc) {
   bool IsSimple = (NumOutputs != 0 || NumInputs != 0);
+  getCurFunction()->setHasBranchProtectedScope();
   MSAsmStmt *NS =
     new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
                             /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
@@ -527,3 +529,31 @@ StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                             Clobbers, EndLoc);
   return NS;
 }
+
+LabelDecl *Sema::GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
+                                       SourceLocation Location,
+                                       bool AlwaysCreate) {
+  LabelDecl* Label = LookupOrCreateLabel(PP.getIdentifierInfo(ExternalLabelName),
+                                         Location);
+
+  if (!Label->isMSAsmLabel()) {
+    // Otherwise, insert it, but only resolve it if we have seen the label itself.
+    std::string InternalName;
+    llvm::raw_string_ostream OS(InternalName);
+    // Create an internal name for the label.  The name should not be a valid mangled
+    // name, and should be unique.  We use a dot to make the name an invalid mangled
+    // name.
+    OS << "__MSASMLABEL_." << MSAsmLabelNameCounter++ << "__" << ExternalLabelName;
+    Label->setMSAsmLabel(OS.str());
+  }
+  if (AlwaysCreate) {
+    // The label might have been created implicitly from a previously encountered
+    // goto statement.  So, for both newly created and looked up labels, we mark
+    // them as resolved.
+    Label->setMSAsmLabelResolved();
+  }
+  // Adjust their location for being able to generate accurate diagnostics.
+  Label->setLocation(Location);
+
+  return Label;
+}