Trailing whitespace.

[oota-llvm.git] / include / llvm / Target / TargetAsmBackend.h

diff --git a/include/llvm/Target/TargetAsmBackend.h b/include/llvm/Target/TargetAsmBackend.h
index 35a995f541e2bff280951e0646dba1d2ddb39f30..b424dea4a56e8feb84420e0989c8e51196693c57 100644 (file)
--- a/include/llvm/Target/TargetAsmBackend.h
+++ b/include/llvm/Target/TargetAsmBackend.h
@@ -10,9 +10,19 @@
 #ifndef LLVM_TARGET_TARGETASMBACKEND_H
 #define LLVM_TARGET_TARGETASMBACKEND_H
 
+#include "llvm/System/DataTypes.h"
+
 namespace llvm {
+class MCDataFragment;
+class MCFixup;
+class MCInst;
+class MCObjectFormat;
+class MCObjectWriter;
 class MCSection;
+template<typename T>
+class SmallVectorImpl;
 class Target;
+class raw_ostream;
 
 /// TargetAsmBackend - Generic interface to target specific assembler backends.
 class TargetAsmBackend {
@@ -24,23 +34,33 @@ protected: // Can only create subclasses.
   /// TheTarget - The Target that this machine was created for.
   const Target &TheTarget;
 
+  unsigned HasReliableSymbolDifference : 1;
+  unsigned HasScatteredSymbols : 1;
+
 public:
   virtual ~TargetAsmBackend();
 
   const Target &getTarget() const { return TheTarget; }
 
-  /// hasAbsolutizedSet - Check whether this target "absolutizes"
-  /// assignments. That is, given code like:
-  ///   a:
-  ///   ...
-  ///   b:
-  ///   tmp = a - b
-  ///       .long tmp
-  /// will the value of 'tmp' be a relocatable expression, or the assembly time
-  /// value of L0 - L1. This distinction is only relevant for platforms that
-  /// support scattered symbols, since in the absence of scattered symbols (a -
-  /// b) cannot change after assembly.
-  virtual bool hasAbsolutizedSet() const { return false; }
+  virtual const MCObjectFormat &getObjectFormat() const = 0;
+
+  /// createObjectWriter - Create a new MCObjectWriter instance for use by the
+  /// assembler backend to emit the final object file.
+  virtual MCObjectWriter *createObjectWriter(raw_ostream &OS) const = 0;
+
+  /// hasReliableSymbolDifference - Check whether this target implements
+  /// accurate relocations for differences between symbols. If not, differences
+  /// between symbols will always be relocatable expressions and any references
+  /// to temporary symbols will be assumed to be in the same atom, unless they
+  /// reside in a different section.
+  ///
+  /// This should always be true (since it results in fewer relocations with no
+  /// loss of functionality), but is currently supported as a way to maintain
+  /// exact object compatibility with Darwin 'as' (on non-x86_64). It should
+  /// eventually should be eliminated.
+  bool hasReliableSymbolDifference() const {
+    return HasReliableSymbolDifference;
+  }
 
   /// hasScatteredSymbols - Check whether this target supports scattered
   /// symbols. If so, the assembler should assume that atoms can be scattered by
@@ -50,13 +70,55 @@ public:
   ///
   /// Note that the assembler currently does not reason about atoms, instead it
   /// assumes all temporary symbols reside in the "current atom".
-  virtual bool hasScatteredSymbols() const { return false; }
+  bool hasScatteredSymbols() const { return HasScatteredSymbols; }
 
   /// doesSectionRequireSymbols - Check whether the given section requires that
   /// all symbols (even temporaries) have symbol table entries.
   virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
     return false;
   }
+
+  /// isSectionAtomizable - Check whether the given section can be split into
+  /// atoms.
+  ///
+  /// \see MCAssembler::isSymbolLinkerVisible().
+  virtual bool isSectionAtomizable(const MCSection &Section) const {
+    return true;
+  }
+
+  /// isVirtualSection - Check whether the given section is "virtual", that is
+  /// has no actual object file contents.
+  virtual bool isVirtualSection(const MCSection &Section) const = 0;
+
+  /// getPointerSize - Get the pointer size in bytes.
+  virtual unsigned getPointerSize() const = 0;
+
+  /// ApplyFixup - Apply the \arg Value for given \arg Fixup into the provided
+  /// data fragment, at the offset specified by the fixup and following the
+  /// fixup kind as appropriate.
+  virtual void ApplyFixup(const MCFixup &Fixup, MCDataFragment &Fragment,
+                          uint64_t Value) const = 0;
+
+  /// MayNeedRelaxation - Check whether the given instruction may need
+  /// relaxation.
+  ///
+  /// \param Inst - The instruction to test.
+  virtual bool MayNeedRelaxation(const MCInst &Inst) const = 0;
+
+  /// RelaxInstruction - Relax the instruction in the given fragment to the next
+  /// wider instruction.
+  ///
+  /// \param Inst - The instruction to relax, which may be the same as the
+  /// output.
+  /// \parm Res [output] - On return, the relaxed instruction.
+  virtual void RelaxInstruction(const MCInst &Inst, MCInst &Res) const = 0;
+
+  /// WriteNopData - Write an (optimal) nop sequence of Count bytes to the given
+  /// output. If the target cannot generate such a sequence, it should return an
+  /// error.
+  ///
+  /// \return - True on success.
+  virtual bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const = 0;
 };
 
 } // End llvm namespace