One instruction may start (or end) multiple lexical scopes.

There is no need to remember labels identifying regions marked by such instructions in each scope.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100781 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 28 insertions, 58 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 8d190372d6..917bd9d2d5 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -192,8 +192,6 @@ class DbgScope {
   // Location at which this scope is inlined.
   AssertingVH<MDNode> InlinedAtLocation;  
   bool AbstractScope;                 // Abstract Scope
-  MCSymbol *StartLabel;               // Label ID of the beginning of scope.
-  MCSymbol *EndLabel;                 // Label ID of the end of scope.
   const MachineInstr *LastInsn;       // Last instruction of this scope.
   const MachineInstr *FirstInsn;      // First instruction of this scope.
   // Scopes defined in scope.  Contents not owned.
@@ -206,7 +204,6 @@ class DbgScope {
 public:
   DbgScope(DbgScope *P, DIDescriptor D, MDNode *I = 0)
     : Parent(P), Desc(D), InlinedAtLocation(I), AbstractScope(false),
-      StartLabel(0), EndLabel(0),
       LastInsn(0), FirstInsn(0), IndentLevel(0) {}
   virtual ~DbgScope();
 
@@ -216,12 +213,8 @@ public:
   DIDescriptor getDesc()         const { return Desc; }
   MDNode *getInlinedAt()         const { return InlinedAtLocation; }
   MDNode *getScopeNode()         const { return Desc.getNode(); }
-  MCSymbol *getStartLabel()      const { return StartLabel; }
-  MCSymbol *getEndLabel()        const { return EndLabel; }
   const SmallVector<DbgScope *, 4> &getScopes() { return Scopes; }
   const SmallVector<DbgVariable *, 8> &getVariables() { return Variables; }
-  void setStartLabel(MCSymbol *S) { StartLabel = S; }
-  void setEndLabel(MCSymbol *E)   { EndLabel = E; }
   void setLastInsn(const MachineInstr *MI) { LastInsn = MI; }
   const MachineInstr *getLastInsn()      { return LastInsn; }
   void setFirstInsn(const MachineInstr *MI) { FirstInsn = MI; }
@@ -287,7 +280,6 @@ void DbgScope::dump() const {
   err.indent(IndentLevel);
   MDNode *N = Desc.getNode();
   N->dump();
-  err << " [" << StartLabel << ", " << EndLabel << "]\n";
   if (AbstractScope)
     err << "Abstract Scope\n";
 
@@ -1406,8 +1398,9 @@ DIE *DwarfDebug::updateSubprogramScopeDIE(MDNode *SPNode) {
 /// constructLexicalScope - Construct new DW_TAG_lexical_block
 /// for this scope and attach DW_AT_low_pc/DW_AT_high_pc labels.
 DIE *DwarfDebug::constructLexicalScopeDIE(DbgScope *Scope) {
-  MCSymbol *Start = Scope->getStartLabel();
-  MCSymbol *End = Scope->getEndLabel();
+  
+  MCSymbol *Start = InsnBeforeLabelMap.lookup(Scope->getFirstInsn());
+  MCSymbol *End = InsnAfterLabelMap.lookup(Scope->getLastInsn());
   if (Start == 0 || End == 0) return 0;
 
   assert(Start->isDefined() && "Invalid starting label for an inlined scope!");
@@ -1430,8 +1423,8 @@ DIE *DwarfDebug::constructLexicalScopeDIE(DbgScope *Scope) {
 /// a function. Construct DIE to represent this concrete inlined copy
 /// of the function.
 DIE *DwarfDebug::constructInlinedScopeDIE(DbgScope *Scope) {
-  MCSymbol *StartLabel = Scope->getStartLabel();
-  MCSymbol *EndLabel = Scope->getEndLabel();
+  MCSymbol *StartLabel = InsnBeforeLabelMap.lookup(Scope->getFirstInsn());
+  MCSymbol *EndLabel = InsnAfterLabelMap.lookup(Scope->getLastInsn());
   if (StartLabel == 0 || EndLabel == 0) return 0;
   
   assert(StartLabel->isDefined() &&
@@ -2137,15 +2130,9 @@ void DwarfDebug::beginScope(const MachineInstr *MI) {
   MCSymbol *Label = recordSourceLine(DL.getLine(), DL.getCol(), Scope);
   PrevInstLoc = DL;
 
-  // update DbgScope if this instruction starts a new scope.
-  InsnToDbgScopeMapTy::iterator I = DbgScopeBeginMap.find(MI);
-  if (I == DbgScopeBeginMap.end())
-    return;
-
-  ScopeVector &SD = I->second;
-  for (ScopeVector::iterator SDI = SD.begin(), SDE = SD.end();
-       SDI != SDE; ++SDI)
-    (*SDI)->setStartLabel(Label);
+  // If this instruction begins a scope then note down corresponding label.
+  if (InsnsBeginScopeSet.count(MI) != 0)
+    InsnBeforeLabelMap[MI] = Label;
 }
 
 /// endScope - Process end of a scope.
@@ -2159,19 +2146,12 @@ void DwarfDebug::endScope(const MachineInstr *MI) {
   if (DL.isUnknown())
     return;
 
-  // Emit a label and update DbgScope if this instruction ends a scope.
-  InsnToDbgScopeMapTy::iterator I = DbgScopeEndMap.find(MI);
-  if (I == DbgScopeEndMap.end())
-    return;
-  
-  MCSymbol *Label = MMI->getContext().CreateTempSymbol();
-  Asm->OutStreamer.EmitLabel(Label);
-
-  SmallVector<DbgScope*, 2> &SD = I->second;
-  for (SmallVector<DbgScope *, 2>::iterator SDI = SD.begin(), SDE = SD.end();
-       SDI != SDE; ++SDI)
-    (*SDI)->setEndLabel(Label);
-  return;
+  if (InsnsEndScopeSet.count(MI) != 0) {
+    // Emit a label if this instruction ends a scope.
+    MCSymbol *Label = MMI->getContext().CreateTempSymbol();
+    Asm->OutStreamer.EmitLabel(Label);
+    InsnAfterLabelMap[MI] = Label;
+  }
 }
 
 /// createDbgScope - Create DbgScope for the scope.
@@ -2288,22 +2268,11 @@ void DwarfDebug::populateDbgScopeInverseMaps() {
 
     if (S->isAbstractScope())
       continue;
-    const MachineInstr *MI = S->getFirstInsn();
-    assert(MI && "DbgScope does not have first instruction!");
+    assert(S->getFirstInsn() && "DbgScope does not have first instruction!");
+    InsnsBeginScopeSet.insert(S->getFirstInsn());
 
-    InsnToDbgScopeMapTy::iterator IDI = DbgScopeBeginMap.find(MI);
-    if (IDI != DbgScopeBeginMap.end())
-      IDI->second.push_back(S);
-    else
-      DbgScopeBeginMap[MI].push_back(S);
-
-    MI = S->getLastInsn();
-    assert(MI && "DbgScope does not have last instruction!");
-    IDI = DbgScopeEndMap.find(MI);
-    if (IDI != DbgScopeEndMap.end())
-      IDI->second.push_back(S);
-    else
-      DbgScopeEndMap[MI].push_back(S);
+    assert(S->getLastInsn() && "DbgScope does not have last instruction!");
+    InsnsEndScopeSet.insert(S->getLastInsn());
   }
 }
 
@@ -2374,8 +2343,6 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
   // Clear debug info
   CurrentFnDbgScope = NULL;
   DeleteContainerSeconds(DbgScopeMap);
-  DbgScopeBeginMap.clear();
-  DbgScopeEndMap.clear();
   DbgValueStartMap.clear();
   ConcreteScopes.clear();
   DeleteContainerSeconds(AbstractScopes);
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 8a38ef10a7..ba3813758d 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -179,14 +179,9 @@ class DwarfDebug {
   SmallPtrSet<DIE *, 4> AbstractSubprogramDIEs;
 
   typedef SmallVector<DbgScope *, 2> ScopeVector;
-  typedef DenseMap<const MachineInstr *, ScopeVector>
-    InsnToDbgScopeMapTy;
 
-  /// DbgScopeBeginMap - Maps instruction with a list of DbgScopes it starts.
-  InsnToDbgScopeMapTy DbgScopeBeginMap;
-
-  /// DbgScopeEndMap - Maps instruction with a list DbgScopes it ends.
-  InsnToDbgScopeMapTy DbgScopeEndMap;
+  SmallPtrSet<const MachineInstr *, 8> InsnsBeginScopeSet;
+  SmallPtrSet<const MachineInstr *, 8> InsnsEndScopeSet;
 
   /// InlineInfo - Keep track of inlined functions and their location.  This
   /// information is used to populate debug_inlined section.
@@ -194,6 +189,14 @@ class DwarfDebug {
   DenseMap<MDNode*, SmallVector<InlineInfoLabels, 4> > InlineInfo;
   SmallVector<MDNode *, 4> InlinedSPNodes;
 
+  /// InsnBeforeLabelMap - Maps instruction with label emitted before 
+  /// instruction.
+  DenseMap<const MachineInstr *, MCSymbol *> InsnBeforeLabelMap;
+
+  /// InsnAfterLabelMap - Maps instruction with label emitted after
+  /// instruction.
+  DenseMap<const MachineInstr *, MCSymbol *> InsnAfterLabelMap;
+
   /// CompileUnitOffsets - A vector of the offsets of the compile units. This is
   /// used when calculating the "origin" of a concrete instance of an inlined
   /// function.