From c35dd25ab820c3db37b7bfd506d656c14b14e331 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Tue, 14 Jun 2011 21:13:25 +0000
Subject: [PATCH] Diagnostic for undefined assembler local symbols.

When an assembler local symbol is used but not defined in a module, a
Darwin assembler wants to issue a diagnostic to that effect.

rdar://9559714


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133010 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/MC/MCContext.h   | 13 ++++++++++++-
 lib/MC/MCParser/AsmParser.cpp | 29 +++++++++++++++++++++++++----
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/include/llvm/MC/MCContext.h b/include/llvm/MC/MCContext.h
index 070089e2c93..43a9ce6cfa4 100644
--- a/include/llvm/MC/MCContext.h
+++ b/include/llvm/MC/MCContext.h
@@ -39,6 +39,9 @@ namespace llvm {
   class MCContext {
     MCContext(const MCContext&); // DO NOT IMPLEMENT
     MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
+  public:
+    typedef StringMap<MCSymbol*, BumpPtrAllocator&> SymbolTable;
+  private:
 
     /// The MCAsmInfo for this target.
     const MCAsmInfo &MAI;
@@ -52,7 +55,7 @@ namespace llvm {
     BumpPtrAllocator Allocator;
 
     /// Symbols - Bindings of names to symbols.
-    StringMap<MCSymbol*, BumpPtrAllocator&> Symbols;
+    SymbolTable Symbols;
 
     /// UsedNames - Keeps tracks of names that were used both for used declared
     /// and artificial symbols.
@@ -142,6 +145,14 @@ namespace llvm {
     /// LookupSymbol - Get the symbol for \p Name, or null.
     MCSymbol *LookupSymbol(StringRef Name) const;
 
+    /// getSymbols - Get a reference for the symbol table for clients that
+    /// want to, for example, iterate over all symbols. 'const' because we
+    /// still want any modifications to the table itself to use the MCContext
+    /// APIs.
+    const SymbolTable &getSymbols() const {
+      return Symbols;
+    }
+
     /// @}
 
     /// @name Section Management
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 4f55cea7bc5..a1c5e6be6a3 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -84,6 +84,7 @@ private:
   AsmLexer Lexer;
   MCContext &Ctx;
   MCStreamer &Out;
+  const MCAsmInfo &MAI;
   SourceMgr &SrcMgr;
   MCAsmParserExtension *GenericParser;
   MCAsmParserExtension *PlatformParser;
@@ -135,7 +136,7 @@ public:
   virtual MCContext &getContext() { return Ctx; }
   virtual MCStreamer &getStreamer() { return Out; }
 
-  virtual bool Warning(SMLoc L, const Twine &Meg);
+  virtual bool Warning(SMLoc L, const Twine &Msg);
   virtual bool Error(SMLoc L, const Twine &Msg);
 
   const AsmToken &Lex();
@@ -160,8 +161,9 @@ private:
   void HandleMacroExit();
 
   void PrintMacroInstantiations();
-  void PrintMessage(SMLoc Loc, const Twine &Msg, const char *Type) const {
-    SrcMgr.PrintMessage(Loc, Msg, Type);
+  void PrintMessage(SMLoc Loc, const Twine &Msg, const char *Type,
+                    bool ShowLine = true) const {
+    SrcMgr.PrintMessage(Loc, Msg, Type, ShowLine);
   }
 
   /// EnterIncludeFile - Enter the specified file. This returns true on failure.
@@ -337,7 +339,7 @@ enum { DEFAULT_ADDRSPACE = 0 };
 
 AsmParser::AsmParser(const Target &T, SourceMgr &_SM, MCContext &_Ctx,
                      MCStreamer &_Out, const MCAsmInfo &_MAI)
-  : Lexer(_MAI), Ctx(_Ctx), Out(_Out), SrcMgr(_SM),
+  : Lexer(_MAI), Ctx(_Ctx), Out(_Out), MAI(_MAI), SrcMgr(_SM),
     GenericParser(new GenericAsmParser), PlatformParser(0),
     CurBuffer(0), MacrosEnabled(true) {
   Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
@@ -466,6 +468,25 @@ bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
       TokError("unassigned file number: " + Twine(i) + " for .file directives");
   }
 
+  // Check to see that all assembler local symbols were actually defined.
+  // Targets that don't do subsections via symbols may not want this, though,
+  // so conservatively exclude them.
+  if (MAI.hasSubsectionsViaSymbols()) {
+    const MCContext::SymbolTable &Symbols = getContext().getSymbols();
+    for (MCContext::SymbolTable::const_iterator i = Symbols.begin(),
+         e = Symbols.end();
+         i != e; ++i) {
+      MCSymbol *Sym = i->getValue();
+      if (Sym->isTemporary() && !Sym->isDefined())
+        // FIXME: We would really like to refer back to where the symbol was
+        // first referenced for a source location. We need to add something
+        // to track that. Currently, we just point to the end of the file.
+        PrintMessage(getLexer().getLoc(), "assembler local symbol '" +
+                     Sym->getName() + "' not defined", "error", false);
+    }
+  }
+
+
   // Finalize the output stream if there are no errors and if the client wants
   // us to.
   if (!HadError && !NoFinalize)
-- 
2.34.1