From c69485e34d57e17fe2c3acab64e519d6a6945197 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 24 Jun 2009 04:31:49 +0000
Subject: [PATCH] add trivial support for passing label definitions through the
 MCStreamer.

This is suboptimal in several aspects, see the commented out assertion.
I need to talk to Daniel about this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74057 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/MC/MCContext.h |  7 +++++++
 lib/MC/MCAsmStreamer.cpp    |  4 ++--
 lib/MC/MCContext.cpp        | 14 ++++++++++++++
 tools/llvm-mc/AsmParser.cpp |  6 ++++++
 tools/llvm-mc/AsmParser.h   |  5 ++++-
 tools/llvm-mc/llvm-mc.cpp   |  3 +--
 6 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/include/llvm/MC/MCContext.h b/include/llvm/MC/MCContext.h
index 3ccc4daa767..8dabb45e9ab 100644
--- a/include/llvm/MC/MCContext.h
+++ b/include/llvm/MC/MCContext.h
@@ -56,6 +56,13 @@ namespace llvm {
     /// @param Name - The symbol name, which must be unique across all symbols.
     MCSymbol *CreateSymbol(MCAtom *Atom, const char *Name);
 
+    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
+    /// @param Name.  If it exists, return it.  If not, create a forward
+    /// reference and return it.
+    ///
+    /// @param Name - The symbol name, which must be unique across all symbols.
+    MCSymbol *GetOrCreateSymbol(const char *Name);
+    
     /// CreateTemporarySymbol - Create a new temporary symbol inside @param Atom
     /// with the specified @param Name.
     ///
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 1956c2e77bd..d268fb75e8f 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -84,8 +84,8 @@ void MCAsmStreamer::SwitchSection(MCSection *Section) {
 void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
   // FIXME: We need to enforce that we aren't printing atoms which are more
   // complicated than the assembler understands.
-  assert(Symbol->getAtom()->getSection() == CurSection && 
-         "The label for a symbol must match its section!");
+  //assert(Symbol->getAtom()->getSection() == CurSection && 
+  //       "The label for a symbol must match its section!");
   OS << Symbol->getName() << ":\n";
 }
 
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index cad0d569902..f7793b918ca 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -44,6 +44,20 @@ MCSymbol *MCContext::CreateSymbol(MCAtom *Atom, const char *Name) {
   return Entry = new (*this) MCSymbol(Atom, Name, false);
 }
 
+/// GetOrCreateSymbol - Lookup the symbol inside with the specified
+/// @param Name.  If it exists, return it.  If not, create a forward
+/// reference and return it.
+///
+/// @param Name - The symbol name, which must be unique across all symbols.
+MCSymbol *MCContext::GetOrCreateSymbol(const char *Name) {
+  MCSymbol *&Entry = Symbols[Name];
+  if (Entry) return Entry;
+
+  // FIXME: is a null atom the right way to make a forward ref?
+  return Entry = new (*this) MCSymbol(0, Name, false);
+}
+
+
 MCSymbol *MCContext::CreateTemporarySymbol(MCAtom *Atom, const char *Name) {
   // If unnamed, just create a symbol.
   if (Name[0] == '\0')
diff --git a/tools/llvm-mc/AsmParser.cpp b/tools/llvm-mc/AsmParser.cpp
index 4dd136d0086..ca0b9338415 100644
--- a/tools/llvm-mc/AsmParser.cpp
+++ b/tools/llvm-mc/AsmParser.cpp
@@ -185,6 +185,12 @@ bool AsmParser::ParseStatement() {
   if (Lexer.Lex() == asmtok::Colon) {
     // identifier ':'   -> Label.
     Lexer.Lex();
+    
+    // Since we saw a label, create a symbol and emit it.
+    // FIXME: If the label starts with L it is an assembler temporary label.
+    // Why does the client of this api need to know this?
+    Out.EmitLabel(Ctx.GetOrCreateSymbol(IDVal));
+    
     return ParseStatement();
   }
   
diff --git a/tools/llvm-mc/AsmParser.h b/tools/llvm-mc/AsmParser.h
index 9a2c6dac4d9..95154485cda 100644
--- a/tools/llvm-mc/AsmParser.h
+++ b/tools/llvm-mc/AsmParser.h
@@ -17,17 +17,20 @@
 #include "AsmLexer.h"
 
 namespace llvm {
+class MCContext;
 class MCInst;
 class MCStreamer;
   
 class AsmParser {
   AsmLexer Lexer;
+  MCContext &Ctx;
   MCStreamer &Out;
   
   struct X86Operand;
   
 public:
-  AsmParser(SourceMgr &SM, MCStreamer &OutStr) : Lexer(SM), Out(OutStr) {}
+  AsmParser(SourceMgr &SM, MCContext &ctx, MCStreamer &OutStr)
+    : Lexer(SM), Ctx(ctx), Out(OutStr) {}
   ~AsmParser() {}
   
   bool Run();
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index fe8af10fb8e..b999109f0bc 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -139,10 +139,9 @@ static int AssembleInput(const char *ProgName) {
   // it later.
   SrcMgr.setIncludeDirs(IncludeDirs);
   
-  // FIXME: don't leak streamer, own.
   MCContext Ctx;
   OwningPtr<MCStreamer> Str(createAsmStreamer(Ctx, outs()));
-  AsmParser Parser(SrcMgr, *Str.get());
+  AsmParser Parser(SrcMgr, Ctx, *Str.get());
   return Parser.Run();
 }