Keep track of artificial scopes introduced by line directives. For example,

#line 41 "bar.c"
  dummy (1, i);
#line 24 "bar.h"
  i = f2 (i);
#line 44 "bar.c"

This is tested by step-line.exp in gdb testsuite.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109189 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDebugInfo.cpp

@@ -1349,6 +1349,8 @@ void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, QualType FnType,
   llvm::StringRef Name;
   llvm::StringRef LinkageName;
 
+  FnBeginRegionCount.push_back(RegionStack.size());
+
   const Decl *D = GD.getDecl();
   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
     // If there is a DISubprogram for  this function available then use it.
@@ -1392,6 +1394,9 @@ void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, QualType FnType,
   llvm::MDNode *SPN = SP;
   RegionStack.push_back(SPN);
   RegionMap[D] = llvm::WeakVH(SP);
+
+  // Clear stack used to keep track of #line directives.
+  LineDirectiveFiles.clear();
 }
 
 
@@ -1417,6 +1422,55 @@ void CGDebugInfo::EmitStopPoint(CGBuilderTy &Builder) {
                                                       Scope));
 }
 
+/// UpdateLineDirectiveRegion - Update region stack only if #line directive
+/// has introduced scope change.
+void CGDebugInfo::UpdateLineDirectiveRegion(CGBuilderTy &Builder) {
+  if (CurLoc.isInvalid() || CurLoc.isMacroID() ||
+      PrevLoc.isInvalid() || PrevLoc.isMacroID())
+    return;
+  SourceManager &SM = CGM.getContext().getSourceManager();
+  PresumedLoc PCLoc = SM.getPresumedLoc(CurLoc);
+  PresumedLoc PPLoc = SM.getPresumedLoc(PrevLoc);
+
+  if (!strcmp(PPLoc.getFilename(), PCLoc.getFilename()))
+    return;
+
+  // If #line directive stack is empty then we are entering a new scope.
+  if (LineDirectiveFiles.empty()) {
+    EmitRegionStart(Builder);
+    LineDirectiveFiles.push_back(PCLoc.getFilename());
+    return;
+  }
+
+  assert (RegionStack.size() >= LineDirectiveFiles.size()
+          && "error handling  #line regions!");
+
+  bool SeenThisFile = false;
+  for(std::vector<const char *>::iterator I = LineDirectiveFiles.begin(),
+        E = LineDirectiveFiles.end(); I != E; ++I)
+    if (!strcmp(PPLoc.getFilename(), *I)) {
+      SeenThisFile = true;
+      break;
+    }
+
+  // If #line for this file is seen earlier then pop out #line regions.
+  if (SeenThisFile) {
+    while (!LineDirectiveFiles.empty()) {
+      const char *LastFile = LineDirectiveFiles.back();
+      RegionStack.pop_back();
+      LineDirectiveFiles.pop_back();
+      if (!strcmp(PPLoc.getFilename(), LastFile))
+        break;
+    }
+    return;
+  } 
+
+  // .. otherwise insert new #line region.
+  EmitRegionStart(Builder);
+  LineDirectiveFiles.push_back(PCLoc.getFilename());
+
+  return;
+}
 /// EmitRegionStart- Constructs the debug code for entering a declarative
 /// region - "llvm.dbg.region.start.".
 void CGDebugInfo::EmitRegionStart(CGBuilderTy &Builder) {
@@ -1442,6 +1496,18 @@ void CGDebugInfo::EmitRegionEnd(CGBuilderTy &Builder) {
   RegionStack.pop_back();
 }
 
+/// EmitFunctionEnd - Constructs the debug code for exiting a function.
+void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder) {
+  assert(!RegionStack.empty() && "Region stack mismatch, stack empty!");
+  unsigned RCount = FnBeginRegionCount.back();
+  assert(RCount <= RegionStack.size() && "Region stack mismatch");
+
+  // Pop all regions for this function.
+  while (RegionStack.size() != RCount)
+    EmitRegionEnd(Builder);
+  FnBeginRegionCount.pop_back();
+}
+
 // EmitTypeForVarWithBlocksAttr - Build up structure info for the byref.  
 // See BuildByRefType.
 llvm::DIType CGDebugInfo::EmitTypeForVarWithBlocksAttr(const ValueDecl *VD,

lib/CodeGen/CGDebugInfo.h

@@ -58,6 +58,14 @@ class CGDebugInfo {
 
   std::vector<llvm::TrackingVH<llvm::MDNode> > RegionStack;
   llvm::DenseMap<const Decl *, llvm::WeakVH> RegionMap;
+  // FnBeginRegionCount - Keep track of RegionStack counter at the beginning
+  // of a function. This is used to pop unbalanced regions at the end of a
+  // function.
+  std::vector<unsigned> FnBeginRegionCount;
+
+  /// LineDirectiveFiles - This stack is used to keep track of 
+  /// scopes introduced by #line directives.
+  std::vector<const char *> LineDirectiveFiles;
 
   /// DebugInfoNames - This is a storage for names that are
   /// constructed on demand. For example, C++ destructors, C++ operators etc..
@@ -134,6 +142,13 @@ public:
   void EmitFunctionStart(GlobalDecl GD, QualType FnType,
                          llvm::Function *Fn, CGBuilderTy &Builder);
 
+  /// EmitFunctionEnd - Constructs the debug code for exiting a function.
+  void EmitFunctionEnd(CGBuilderTy &Builder);
+
+  /// UpdateLineDirectiveRegion - Update region stack only if #line directive
+  /// has introduced scope change.
+  void UpdateLineDirectiveRegion(CGBuilderTy &Builder);
+
   /// EmitRegionStart - Emit a call to llvm.dbg.region.start to indicate start
   /// of a new block.
   void EmitRegionStart(CGBuilderTy &Builder);

lib/CodeGen/CGStmt.cpp

@@ -34,6 +34,7 @@ void CodeGenFunction::EmitStopPoint(const Stmt *S) {
       DI->setLocation(S->getLocEnd());
     else
       DI->setLocation(S->getLocStart());
+    DI->UpdateLineDirectiveRegion(Builder);
     DI->EmitStopPoint(Builder);
   }
 }

lib/CodeGen/CodeGenFunction.cpp

@@ -139,7 +139,7 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
   // Emit debug descriptor for function end.
   if (CGDebugInfo *DI = getDebugInfo()) {
     DI->setLocation(EndLoc);
-    DI->EmitRegionEnd(Builder);
+    DI->EmitFunctionEnd(Builder);
   }
 
   EmitFunctionEpilog(*CurFnInfo);