Use printable names to implement directional labels.

This changes the implementation of local directional labels to use a dedicated
map. With that it can then just use CreateTempSymbol, which is what the rest
of MC uses.

CreateTempSymbol doesn't do a great job at making sure the names are unique
(or being efficient when the names are not needed), but that should probably
be fixed in a followup patch.

This fixes pr18928.

llvm-svn: 203826

3 files changed, 22 insertions, 16 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 7f211255c6f..27f66d8393f 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -162,32 +162,39 @@ MCSymbol *MCContext::CreateTempSymbol() {
   return CreateSymbol(NameSV);
 }
 
-unsigned MCContext::NextInstance(int64_t LocalLabelVal) {
+unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
   MCLabel *&Label = Instances[LocalLabelVal];
   if (!Label)
     Label = new (*this) MCLabel(0);
   return Label->incInstance();
 }
 
-unsigned MCContext::GetInstance(int64_t LocalLabelVal) {
+unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
   MCLabel *&Label = Instances[LocalLabelVal];
   if (!Label)
     Label = new (*this) MCLabel(0);
   return Label->getInstance();
 }
 
-MCSymbol *MCContext::CreateDirectionalLocalSymbol(int64_t LocalLabelVal) {
-  return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
-                           Twine(LocalLabelVal) +
-                           "\2" +
-                           Twine(NextInstance(LocalLabelVal)));
+MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
+                                                       unsigned Instance) {
+  MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
+  if (!Sym)
+    Sym = CreateTempSymbol();
+  return Sym;
+}
+
+MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
+  unsigned Instance = NextInstance(LocalLabelVal);
+  return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
 }
-MCSymbol *MCContext::GetDirectionalLocalSymbol(int64_t LocalLabelVal,
-                                               int bORf) {
-  return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
-                           Twine(LocalLabelVal) +
-                           "\2" +
-                           Twine(GetInstance(LocalLabelVal) + bORf));
+
+MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
+                                               bool Before) {
+  unsigned Instance = GetInstance(LocalLabelVal);
+  if (!Before)
+    ++Instance;
+  return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
 }
 
 MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 3d2131f10be..db448ae8be2 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -884,7 +884,7 @@ bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
       }
       if (IDVal == "f" || IDVal == "b") {
         MCSymbol *Sym =
-            Ctx.GetDirectionalLocalSymbol(IntVal, IDVal == "f" ? 1 : 0);
+            Ctx.GetDirectionalLocalSymbol(IntVal, IDVal == "b");
         Res = MCSymbolRefExpr::Create(Sym, Variant, getContext());
         if (IDVal == "b" && Sym->isUndefined())
           return Error(Loc, "invalid reference to undefined symbol");
diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 5f5f66b0972..0336c161ca4 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1105,8 +1105,7 @@ bool X86AsmParser::ParseIntelExpression(IntelExprStateMachine &SM, SMLoc &End) {
         StringRef IDVal = getTok().getString();
         if (IDVal == "f" || IDVal == "b") {
           MCSymbol *Sym =
-            getContext().GetDirectionalLocalSymbol(IntVal,
-                                                   IDVal == "f" ? 1 : 0);
+              getContext().GetDirectionalLocalSymbol(IntVal, IDVal == "b");
           MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
           const MCExpr *Val = 
 	    MCSymbolRefExpr::Create(Sym, Variant, getContext());