Added support in MC for Directional Local Labels.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103989 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCContext.h

@@ -20,6 +20,7 @@ namespace llvm {
   class MCExpr;
   class MCSection;
   class MCSymbol;
+  class MCLabel;
   class StringRef;
   class Twine;
   class MCSectionMachO;
@@ -43,6 +44,15 @@ namespace llvm {
     /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
     /// symbol.
     unsigned NextUniqueID;
+
+    /// Instances of directional local labels.
+    DenseMap<unsigned, MCLabel *> Instances;
+    /// NextInstance() creates the next instance of the directional local label
+    /// for the LocalLabelVal and adds it to the map if needed.
+    unsigned NextInstance(int64_t LocalLabelVal);
+    /// GetInstance() gets the current instance of the directional local label
+    /// for the LocalLabelVal and adds it to the map if needed.
+    unsigned GetInstance(int64_t LocalLabelVal);
     
     /// Allocator - Allocator object used for creating machine code objects.
     ///
@@ -64,6 +74,14 @@ namespace llvm {
     /// with a unique but unspecified name.
     MCSymbol *CreateTempSymbol();
 
+    /// CreateDirectionalLocalSymbol - Create the defintion of a directional
+    /// local symbol for numbered label (used for "1:" defintions).
+    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
+
+    /// GetDirectionalLocalSymbol - Create and return a directional local
+    /// symbol for numbered label (used for "1b" or 1f" references).
+    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
+
     /// GetOrCreateSymbol - Lookup the symbol inside with the specified
     /// @p Name.  If it exists, return it.  If not, create a forward
     /// reference and return it.

include/llvm/MC/MCLabel.h

@@ -0,0 +1,56 @@
+//===- MCLabel.h - Machine Code Directional Local Labels --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the MCLabel class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCLABEL_H
+#define LLVM_MC_MCLABEL_H
+
+namespace llvm {
+  class MCContext;
+  class raw_ostream;
+
+  /// MCLabel - Instances of this class represent a label name in the MC file,
+  /// and MCLabel are created and unique'd by the MCContext class.  MCLabel
+  /// should only be constructed for valid instances in the object file.
+  class MCLabel {
+    // Instance - the instance number of this Directional Local Label
+    unsigned Instance;
+
+  private:  // MCContext creates and uniques these.
+    friend class MCContext;
+    MCLabel(unsigned instance)
+      : Instance(instance) {}
+
+    MCLabel(const MCLabel&);       // DO NOT IMPLEMENT
+    void operator=(const MCLabel&); // DO NOT IMPLEMENT
+  public:
+    /// getInstance - Get the current instance of this Directional Local Label.
+    unsigned getInstance() const { return Instance; }
+
+    /// incInstance - Increment the current instance of this Directional Local
+    /// Label.
+    unsigned incInstance() { return ++Instance; }
+
+    /// print - Print the value to the stream \arg OS.
+    void print(raw_ostream &OS) const;
+
+    /// dump - Print the value to stderr.
+    void dump() const;
+  };
+
+  inline raw_ostream &operator<<(raw_ostream &OS, const MCLabel &Label) {
+    Label.print(OS);
+    return OS;
+  }
+} // end namespace llvm
+
+#endif

lib/MC/CMakeLists.txt

@@ -10,6 +10,7 @@ add_llvm_library(LLVMMC
   MCExpr.cpp
   MCInst.cpp
   MCInstPrinter.cpp
+  MCLabel.cpp
   MCMachOStreamer.cpp
   MCNullStreamer.cpp
   MCObjectWriter.cpp

lib/MC/MCContext.cpp

@@ -13,6 +13,7 @@
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionCOFF.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCLabel.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 using namespace llvm;
@@ -71,6 +72,50 @@ MCSymbol *MCContext::CreateTempSymbol() {
                            "tmp" + Twine(NextUniqueID++));
 }
 
+unsigned MCContext::NextInstance(int64_t LocalLabelVal) {
+  unsigned Instance;
+  MCLabel *Label;
+  Label = Instances[LocalLabelVal];
+  if (Label) {
+    Instance = Label->incInstance();
+  }
+  else {
+    Instance = 1;
+    Label = new MCLabel(Instance);
+    Instances[LocalLabelVal] = Label;
+  }
+  return Instance;
+}
+
+unsigned MCContext::GetInstance(int64_t LocalLabelVal) {
+  int Instance;
+  MCLabel *Label;
+  Label = Instances[LocalLabelVal];
+  if (Label) {
+    Instance = Label->getInstance();
+  }
+  else {
+    Instance = 0;
+    Label = new MCLabel(Instance);
+    Instances[LocalLabelVal] = Label;
+  }
+  return Instance;
+}
+
+MCSymbol *MCContext::CreateDirectionalLocalSymbol(int64_t LocalLabelVal) {
+  return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
+                           Twine(LocalLabelVal) +
+                           "\2" +
+			   Twine(NextInstance(LocalLabelVal)));
+}
+MCSymbol *MCContext::GetDirectionalLocalSymbol(int64_t LocalLabelVal,
+                                               int bORf) {
+  return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
+                           Twine(LocalLabelVal) +
+                           "\2" +
+			   Twine(GetInstance(LocalLabelVal) + bORf));
+}
+
 MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
   return Symbols.lookup(Name);
 }

lib/MC/MCLabel.cpp

@@ -0,0 +1,21 @@
+//===- lib/MC/MCLabel.cpp - MCLabel implementation ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCLabel.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+void MCLabel::print(raw_ostream &OS) const {
+  OS << '"' << getInstance() << '"';
+}
+
+void MCLabel::dump() const {
+  print(dbgs());
+}

lib/MC/MCParser/AsmLexer.cpp

@@ -132,11 +132,6 @@ AsmToken AsmLexer::LexLineComment() {
 ///   Decimal integer: [1-9][0-9]*
 /// TODO: FP literal.
 AsmToken AsmLexer::LexDigit() {
-  if (*CurPtr == ':')
-    return ReturnError(TokStart, "FIXME: local label not implemented");
-  if (*CurPtr == 'f' || *CurPtr == 'b')
-    return ReturnError(TokStart, "FIXME: directional label not implemented");
-  
   // Decimal integer: [1-9][0-9]*
   if (CurPtr[-1] != '0') {
     while (isdigit(*CurPtr))
@@ -158,6 +153,13 @@ AsmToken AsmLexer::LexDigit() {
   
   if (*CurPtr == 'b') {
     ++CurPtr;
+    // See if we actually have "0b" as part of something like "jmp 0b\n"
+    if (CurPtr[0] == '\n') {
+      --CurPtr;
+      StringRef Result(TokStart, CurPtr - TokStart);
+      ++CurPtr;
+      return AsmToken(AsmToken::Integer, Result, 0);
+    }
     const char *NumStart = CurPtr;
     while (CurPtr[0] == '0' || CurPtr[0] == '1')
       ++CurPtr;

lib/MC/MCParser/AsmParser.cpp

@@ -214,11 +214,28 @@ bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
     Res = MCSymbolRefExpr::Create(Sym, Variant, getContext());
     return false;
   }
-  case AsmToken::Integer:
-    Res = MCConstantExpr::Create(getTok().getIntVal(), getContext());
+  case AsmToken::Integer: {
+    SMLoc Loc = getTok().getLoc();
+    int64_t IntVal = getTok().getIntVal();
+    Res = MCConstantExpr::Create(IntVal, getContext());
     EndLoc = Lexer.getLoc();
     Lex(); // Eat token.
+    // Look for 'b' or 'f' following an Integer as a directional label
+    if (Lexer.getKind() == AsmToken::Identifier) {
+      StringRef IDVal = getTok().getString();
+      if (IDVal == "f" || IDVal == "b"){
+        MCSymbol *Sym = Ctx.GetDirectionalLocalSymbol(IntVal,
+                                                      IDVal == "f" ? 1 : 0);
+        Res = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_None,
+                                      getContext());
+        if(IDVal == "b" && Sym->isUndefined())
+          return Error(Loc, "invalid reference to undefined symbol");
+        EndLoc = Lexer.getLoc();
+        Lex(); // Eat identifier.
+      }
+    }
     return false;
+  }
   case AsmToken::Dot: {
     // This is a '.' reference, which references the current PC.  Emit a
     // temporary label to the streamer and refer to it.
@@ -422,7 +439,25 @@ bool AsmParser::ParseStatement() {
   AsmToken ID = getTok();
   SMLoc IDLoc = ID.getLoc();
   StringRef IDVal;
-  if (ParseIdentifier(IDVal)) {
+  int64_t LocalLabelVal = -1;
+  // GUESS allow an integer followed by a ':' as a directional local label
+  if (Lexer.is(AsmToken::Integer)) {
+    LocalLabelVal = getTok().getIntVal();
+    if (LocalLabelVal < 0) {
+      if (!TheCondState.Ignore)
+        return TokError("unexpected token at start of statement");
+      IDVal = "";
+    }
+    else {
+      IDVal = getTok().getString();
+      Lex(); // Consume the integer token to be used as an identifier token.
+      if (Lexer.getKind() != AsmToken::Colon) {
+	  if (!TheCondState.Ignore)
+	    return TokError("unexpected token at start of statement");
+      }
+    }
+  }
+  else if (ParseIdentifier(IDVal)) {
     if (!TheCondState.Ignore)
       return TokError("unexpected token at start of statement");
     IDVal = "";
@@ -459,7 +494,11 @@ bool AsmParser::ParseStatement() {
     // FIXME: Diagnostics. Note the location of the definition as a label.
     // FIXME: This doesn't diagnose assignment to a symbol which has been
     // implicitly marked as external.
-    MCSymbol *Sym = CreateSymbol(IDVal);
+    MCSymbol *Sym;
+    if (LocalLabelVal == -1)
+      Sym = CreateSymbol(IDVal);
+    else
+      Sym = Ctx.CreateDirectionalLocalSymbol(LocalLabelVal);
     if (!Sym->isUndefined() || Sym->isVariable())
       return Error(IDLoc, "invalid symbol redefinition");
     

test/MC/MachO/direction_labels.s

@@ -0,0 +1,92 @@
+// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump --dump-section-data | FileCheck %s
+
+direction_labels:
+10:	nop
+	jmp 10b
+	nop
+	jmp 11f
+11:	nop
+	ret
+
+// CHECK: ('cputype', 7)
+// CHECK: ('cpusubtype', 3)
+// CHECK: ('filetype', 1)
+// CHECK: ('num_load_commands', 1)
+// CHECK: ('load_commands_size', 228)
+// CHECK: ('flag', 0)
+// CHECK: ('load_commands', [
+// CHECK:   # Load Command 0
+// CHECK:  (('command', 1)
+// CHECK:   ('size', 124)
+// CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('vm_addr', 0)
+// CHECK:   ('vm_size', 8)
+// CHECK:   ('file_offset', 256)
+// CHECK:   ('file_size', 8)
+// CHECK:   ('maxprot', 7)
+// CHECK:   ('initprot', 7)
+// CHECK:   ('num_sections', 1)
+// CHECK:   ('flags', 0)
+// CHECK:   ('sections', [
+// CHECK:     # Section 0
+// CHECK:    (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 8)
+// CHECK:     ('offset', 256)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x80000400)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:   ('_section_data', '\x90\xeb\xfd\x90\xeb\x00\x90\xc3')
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 1
+// CHECK:  (('command', 2)
+// CHECK:   ('size', 24)
+// CHECK:   ('symoff', 264)
+// CHECK:   ('nsyms', 1)
+// CHECK:   ('stroff', 276)
+// CHECK:   ('strsize', 20)
+// CHECK:   ('_string_data', '\x00direction_labels\x00\x00\x00')
+// CHECK:   ('_symbols', [
+// CHECK:     # Symbol 0
+// CHECK:    (('n_strx', 1)
+// CHECK:     ('n_type', 0xe)
+// CHECK:     ('n_sect', 1)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 0)
+// CHECK:     ('_string', 'direction_labels')
+// CHECK:    ),
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 2
+// CHECK:  (('command', 11)
+// CHECK:   ('size', 80)
+// CHECK:   ('ilocalsym', 0)
+// CHECK:   ('nlocalsym', 1)
+// CHECK:   ('iextdefsym', 1)
+// CHECK:   ('nextdefsym', 0)
+// CHECK:   ('iundefsym', 1)
+// CHECK:   ('nundefsym', 0)
+// CHECK:   ('tocoff', 0)
+// CHECK:   ('ntoc', 0)
+// CHECK:   ('modtaboff', 0)
+// CHECK:   ('nmodtab', 0)
+// CHECK:   ('extrefsymoff', 0)
+// CHECK:   ('nextrefsyms', 0)
+// CHECK:   ('indirectsymoff', 0)
+// CHECK:   ('nindirectsyms', 0)
+// CHECK:   ('extreloff', 0)
+// CHECK:   ('nextrel', 0)
+// CHECK:   ('locreloff', 0)
+// CHECK:   ('nlocrel', 0)
+// CHECK:   ('_indirect_symbols', [
+// CHECK:   ])
+// CHECK:  ),
+// CHECK: ])