fix unnamed fiefield issue and add tests for __builtin_preserve_access_index intrinsic

This is a followup patch for https://reviews.llvm.org/D61809.
Handle unnamed bitfield properly and add more test cases.

Fixed the unnamed bitfield issue. The unnamed bitfield is ignored
by debug info, so we need to ignore such a struct/union member
when we try to get the member index in the debug info.

D61809 contains two test cases but not enough as it does
not checking generated IRs in the fine grain level, and also
it does not have semantics checking tests.
This patch added unit tests for both code gen and semantics checking for
the new intrinsic.

Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 366076

2 files changed, 22 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 62d930ca8c4..25d2424eb85 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3892,6 +3892,23 @@ LValue CodeGenFunction::EmitLValueForLambdaField(const FieldDecl *Field) {
   return EmitLValueForField(LambdaLV, Field);
 }
 
+/// Get the field index in the debug info. The debug info structure/union
+/// will ignore the unnamed bitfields.
+unsigned CodeGenFunction::getDebugInfoFIndex(const RecordDecl *Rec,
+                                             unsigned FieldIndex) {
+  unsigned I = 0, Skipped = 0;
+
+  for (auto F : Rec->getDefinition()->fields()) {
+    if (I == FieldIndex)
+      break;
+    if (F->isUnnamedBitfield())
+      Skipped++;
+    I++;
+  }
+
+  return FieldIndex - Skipped;
+}
+
 /// Get the address of a zero-sized field within a record. The resulting
 /// address doesn't necessarily have the right type.
 static Address emitAddrOfZeroSizeField(CodeGenFunction &CGF, Address Base,
@@ -3931,7 +3948,7 @@ static Address emitPreserveStructAccess(CodeGenFunction &CGF, Address base,
       CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
 
   return CGF.Builder.CreatePreserveStructAccessIndex(
-      base, idx, field->getFieldIndex(), DbgInfo);
+      base, idx, CGF.getDebugInfoFIndex(rec, field->getFieldIndex()), DbgInfo);
 }
 
 static bool hasAnyVptr(const QualType Type, const ASTContext &Context) {
@@ -4048,7 +4065,7 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
           getContext().getRecordType(rec), rec->getLocation());
       addr = Address(
           Builder.CreatePreserveUnionAccessIndex(
-              addr.getPointer(), field->getFieldIndex(), DbgInfo),
+              addr.getPointer(), getDebugInfoFIndex(rec, field->getFieldIndex()), DbgInfo),
           addr.getAlignment());
     }
   } else {
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index a51a9711ff1..0d534af42cd 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -2652,6 +2652,9 @@ public:
   /// Converts Location to a DebugLoc, if debug information is enabled.
   llvm::DebugLoc SourceLocToDebugLoc(SourceLocation Location);
 
+  /// Get the record field index as represented in debug info.
+  unsigned getDebugInfoFIndex(const RecordDecl *Rec, unsigned FieldIndex);
+
 
   //===--------------------------------------------------------------------===//
   //                            Declaration Emission