[DebugInfo] Introduce DIEExpr variant of DIEValue to hold MCExpr values

This partially reverts r185202 and restores DIELabel to hold plain
MCSymbol references.  Instead, we add a new subclass DIEExpr of
DIEValue that can hold generic MCExpr references.

This is in preparation for supporting debug info for TLS variables
on PowerPC, where we need to describe the variable location using
a more complex expression than just MCSymbolRefExpr.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185458 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 80 insertions, 21 deletions

diff --git a/lib/CodeGen/AsmPrinter/DIE.cpp b/lib/CodeGen/AsmPrinter/DIE.cpp
index 81bab33..4b6698e 100644
--- a/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -247,13 +247,39 @@ void DIEInteger::print(raw_ostream &O) const {
 #endif
 
 //===----------------------------------------------------------------------===//
+// DIEExpr Implementation
+//===----------------------------------------------------------------------===//
+
+/// EmitValue - Emit expression value.
+///
+void DIEExpr::EmitValue(AsmPrinter *AP, unsigned Form) const {
+  AP->OutStreamer.EmitValue(Expr, SizeOf(AP, Form));
+}
+
+/// SizeOf - Determine size of expression value in bytes.
+///
+unsigned DIEExpr::SizeOf(AsmPrinter *AP, unsigned Form) const {
+  if (Form == dwarf::DW_FORM_data4) return 4;
+  if (Form == dwarf::DW_FORM_sec_offset) return 4;
+  if (Form == dwarf::DW_FORM_strp) return 4;
+  return AP->getDataLayout().getPointerSize();
+}
+
+#ifndef NDEBUG
+void DIEExpr::print(raw_ostream &O) const {
+  O << "Expr: ";
+  Expr->print(O);
+}
+#endif
+
+//===----------------------------------------------------------------------===//
 // DIELabel Implementation
 //===----------------------------------------------------------------------===//
 
 /// EmitValue - Emit label value.
 ///
 void DIELabel::EmitValue(AsmPrinter *AP, unsigned Form) const {
-  AP->OutStreamer.EmitValue(Label, SizeOf(AP, Form));
+  AP->EmitLabelReference(Label, SizeOf(AP, Form));
 }
 
 /// SizeOf - Determine size of label value in bytes.
@@ -267,7 +293,7 @@ unsigned DIELabel::SizeOf(AsmPrinter *AP, unsigned Form) const {
 
 #ifndef NDEBUG
 void DIELabel::print(raw_ostream &O) const {
-  O << "Lbl: " << Label->getSymbol().getName();
+  O << "Lbl: " << Label->getName();
 }
 #endif
 
diff --git a/lib/CodeGen/AsmPrinter/DIE.h b/lib/CodeGen/AsmPrinter/DIE.h
index eaa61d9..412c09c 100644
--- a/lib/CodeGen/AsmPrinter/DIE.h
+++ b/lib/CodeGen/AsmPrinter/DIE.h
@@ -190,6 +190,7 @@ namespace llvm {
     enum {
       isInteger,
       isString,
+      isExpr,
       isLabel,
       isDelta,
       isEntry,
@@ -263,14 +264,40 @@ namespace llvm {
   };
 
   //===--------------------------------------------------------------------===//
-  /// DIELabel - A label expression DIE.
+  /// DIEExpr - An expression DIE.
+  //
+  class DIEExpr : public DIEValue {
+    const MCExpr *Expr;
+  public:
+    explicit DIEExpr(const MCExpr *E) : DIEValue(isExpr), Expr(E) {}
+
+    /// EmitValue - Emit expression value.
+    ///
+    virtual void EmitValue(AsmPrinter *AP, unsigned Form) const;
+
+    /// getValue - Get MCExpr.
+    ///
+    const MCExpr *getValue() const { return Expr; }
+
+    /// SizeOf - Determine size of expression value in bytes.
+    ///
+    virtual unsigned SizeOf(AsmPrinter *AP, unsigned Form) const;
+
+    // Implement isa/cast/dyncast.
+    static bool classof(const DIEValue *E) { return E->getType() == isExpr; }
+
+#ifndef NDEBUG
+    virtual void print(raw_ostream &O) const;
+#endif
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// DIELabel - A label DIE.
   //
   class DIELabel : public DIEValue {
-    const MCSymbolRefExpr *Label;
+    const MCSymbol *Label;
   public:
-    explicit DIELabel(const MCSymbolRefExpr *L) : DIEValue(isLabel), Label(L) {}
-    explicit DIELabel(const MCSymbol *Sym, MCContext &Ctxt)
-        : DIEValue(isLabel), Label(MCSymbolRefExpr::Create(Sym, Ctxt)) {}
+    explicit DIELabel(const MCSymbol *L) : DIEValue(isLabel), Label(L) {}
 
     /// EmitValue - Emit label value.
     ///
@@ -278,7 +305,7 @@ namespace llvm {
 
     /// getValue - Get MCSymbol.
     ///
-    const MCSymbolRefExpr *getValue() const { return Label; }
+    const MCSymbol *getValue() const { return Label; }
 
     /// SizeOf - Determine size of label value in bytes.
     ///
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index f42a33e..398718d 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -136,7 +136,7 @@ void CompileUnit::addString(DIE *Die, unsigned Attribute, StringRef String) {
     MCSymbol *Symb = DU->getStringPoolEntry(String);
     DIEValue *Value;
     if (Asm->needsRelocationsForDwarfStringPool())
-      Value = new (DIEValueAllocator) DIELabel(Symb, Asm->OutContext);
+      Value = new (DIEValueAllocator) DIELabel(Symb);
     else {
       MCSymbol *StringPool = DU->getStringPoolSym();
       Value = new (DIEValueAllocator) DIEDelta(Symb, StringPool);
@@ -156,7 +156,7 @@ void CompileUnit::addLocalString(DIE *Die, unsigned Attribute,
   MCSymbol *Symb = DU->getStringPoolEntry(String);
   DIEValue *Value;
   if (Asm->needsRelocationsForDwarfStringPool())
-    Value = new (DIEValueAllocator) DIELabel(Symb, Asm->OutContext);
+    Value = new (DIEValueAllocator) DIELabel(Symb);
   else {
     MCSymbol *StringPool = DU->getStringPoolSym();
     Value = new (DIEValueAllocator) DIEDelta(Symb, StringPool);
@@ -164,17 +164,20 @@ void CompileUnit::addLocalString(DIE *Die, unsigned Attribute,
   Die->addValue(Attribute, dwarf::DW_FORM_strp, Value);
 }
 
-/// addLabel - Add a Dwarf label attribute data and value.
+/// addExpr - Add a Dwarf expression attribute data and value.
 ///
-void CompileUnit::addLabel(DIE *Die, unsigned Attribute, unsigned Form,
-                           const MCSymbolRefExpr *Label) {
-  DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
+void CompileUnit::addExpr(DIE *Die, unsigned Attribute, unsigned Form,
+                          const MCExpr *Expr) {
+  DIEValue *Value = new (DIEValueAllocator) DIEExpr(Expr);
   Die->addValue(Attribute, Form, Value);
 }
 
+/// addLabel - Add a Dwarf label attribute data and value.
+///
 void CompileUnit::addLabel(DIE *Die, unsigned Attribute, unsigned Form,
                            const MCSymbol *Label) {
-  addLabel(Die, Attribute, Form, MCSymbolRefExpr::Create(Label, Asm->OutContext));
+  DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
+  Die->addValue(Attribute, Form, Value);
 }
 
 /// addLabelAddress - Add a dwarf label attribute data and value using
@@ -184,7 +187,7 @@ void CompileUnit::addLabelAddress(DIE *Die, unsigned Attribute,
                                   MCSymbol *Label) {
   if (!DD->useSplitDwarf()) {
     if (Label != NULL) {
-      DIEValue *Value = new (DIEValueAllocator) DIELabel(Label, Asm->OutContext);
+      DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
       Die->addValue(Attribute, dwarf::DW_FORM_addr, Value);
     } else {
       DIEValue *Value = new (DIEValueAllocator) DIEInteger(0);
@@ -1363,7 +1366,7 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
         addUInt(Block, 0, dwarf::DW_FORM_data1,
                 PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
         // 2) containing the (relocated) address of the TLS variable
-        addLabel(Block, 0, dwarf::DW_FORM_udata, Ref);
+        addExpr(Block, 0, dwarf::DW_FORM_udata, Ref);
       } else {
         addUInt(Block, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
         addUInt(Block, 0, dwarf::DW_FORM_udata, DU->getAddrPoolIndex(Ref));
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 3a95195..7fbf4af 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -218,11 +218,14 @@ public:
   ///
   void addLocalString(DIE *Die, unsigned Attribute, const StringRef Str);
 
+  /// addExpr - Add a Dwarf expression attribute data and value.
+  ///
+  void addExpr(DIE *Die, unsigned Attribute, unsigned Form,
+               const MCExpr *Expr);
+
   /// addLabel - Add a Dwarf label attribute data and value.
   ///
   void addLabel(DIE *Die, unsigned Attribute, unsigned Form,
-                const MCSymbolRefExpr *Label);
-  void addLabel(DIE *Die, unsigned Attribute, unsigned Form,
                 const MCSymbol *Label);
 
   /// addLabelAddress - Add a dwarf label attribute data and value using
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 45f824f..7195709 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1922,9 +1922,9 @@ void DwarfDebug::emitDIE(DIE *Die, std::vector<DIEAbbrev *> *Abbrevs) {
     case dwarf::DW_AT_location: {
       if (DIELabel *L = dyn_cast<DIELabel>(Values[i])) {
         if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-          Asm->EmitLabelReference(&L->getValue()->getSymbol(), 4);
+          Asm->EmitLabelReference(L->getValue(), 4);
         else
-          Asm->EmitLabelDifference(&L->getValue()->getSymbol(), DwarfDebugLocSectionSym, 4);
+          Asm->EmitLabelDifference(L->getValue(), DwarfDebugLocSectionSym, 4);
       } else {
         Values[i]->EmitValue(Asm, Form);
       }