Use NoDebug compile units to mark debug metadata used only for sample-based

profiling and optimization remarks and indicate that no debug info shall
be emitted for these compile units.

http://reviews.llvm.org/D18808
<rdar://problem/25427165>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@265862 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDebugInfo.cpp

@@ -396,16 +396,27 @@ void CGDebugInfo::CreateCompileUnit() {
   if (LO.ObjC1)
     RuntimeVers = LO.ObjCRuntime.isNonFragile() ? 2 : 1;
 
+  llvm::DICompileUnit::DebugEmissionKind EmissionKind;
+  switch (DebugKind) {
+  case codegenoptions::NoDebugInfo:
+  case codegenoptions::LocTrackingOnly:
+    EmissionKind = llvm::DICompileUnit::NoDebug;
+    break;
+  case codegenoptions::DebugLineTablesOnly:
+    EmissionKind = llvm::DICompileUnit::LineTablesOnly;
+    break;
+  case codegenoptions::LimitedDebugInfo:
+  case codegenoptions::FullDebugInfo:
+    EmissionKind = llvm::DICompileUnit::FullDebug;
+    break;
+  }
+
   // Create new compile unit.
   // FIXME - Eliminate TheCU.
   TheCU = DBuilder.createCompileUnit(
       LangTag, remapDIPath(MainFileName), remapDIPath(getCurrentDirname()),
       Producer, LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers,
-      CGM.getCodeGenOpts().SplitDwarfFile,
-      DebugKind <= codegenoptions::DebugLineTablesOnly
-          ? llvm::DICompileUnit::LineTablesOnly
-          : llvm::DICompileUnit::FullDebug,
-      0 /* DWOid */, DebugKind != codegenoptions::LocTrackingOnly);
+      CGM.getCodeGenOpts().SplitDwarfFile, EmissionKind, 0 /* DWOid */);
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {

test/Frontend/optimization-remark.c

@@ -27,9 +27,10 @@
 // CHECK: , !dbg !
 // CHECK-NOT: DW_TAG_base_type
 
-// But llvm.dbg.cu should be missing (to prevent writing debug info to
+// The CU should be marked NoDebug (to prevent writing debug info to
 // the final output).
-// CHECK-NOT: !llvm.dbg.cu = !{
+// CHECK: !llvm.dbg.cu = !{![[CU:.*]]}
+// CHECK: ![[CU]] = distinct !DICompileUnit({{.*}}emissionKind: NoDebug
 
 int foo(int x, int y) __attribute__((always_inline));
 int foo(int x, int y) { return x + y; }

test/Frontend/profile-sample-use-loc-tracking.c

@@ -10,9 +10,10 @@
 // CHECK: , !dbg !
 // CHECK-NOT: DW_TAG_base_type
 
-// But llvm.dbg.cu should be missing (to prevent writing debug info to
+// The CU should be marked NoDebug (to prevent writing debug info to
 // the final output).
-// CHECK-NOT: !llvm.dbg.cu = !{
+// CHECK: !llvm.dbg.cu = !{![[CU:.*]]}
+// CHECK: ![[CU]] = distinct !DICompileUnit({{.*}}emissionKind: NoDebug
 
 int bar(int j) {
   return (j + j - 2) * (j - 2) * j;