CodeGen: Stick constant pool entries in COMDAT sections for WinCOFF

[oota-llvm.git] / include / llvm / MC / MCAsmBackend.h

diff --git a/include/llvm/MC/MCAsmBackend.h b/include/llvm/MC/MCAsmBackend.h
index 43aceba3e14526c2de41fd01be2f5808e4888ecd..82b65fdaf5c8822d363e3e0257d0e7a1fe6fd708 100644 (file)
--- a/include/llvm/MC/MCAsmBackend.h
+++ b/include/llvm/MC/MCAsmBackend.h
@@ -10,7 +10,9 @@
 #ifndef LLVM_MC_MCASMBACKEND_H
 #define LLVM_MC_MCASMBACKEND_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCFixup.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -22,7 +24,7 @@ class MCELFObjectTargetWriter;
 struct MCFixupKindInfo;
 class MCFragment;
 class MCInst;
-class MCInstFragment;
+class MCRelaxableFragment;
 class MCObjectWriter;
 class MCSection;
 class MCValue;
@@ -32,38 +34,32 @@ class raw_ostream;
 class MCAsmBackend {
   MCAsmBackend(const MCAsmBackend &) LLVM_DELETED_FUNCTION;
   void operator=(const MCAsmBackend &) LLVM_DELETED_FUNCTION;
+
 protected: // Can only create subclasses.
   MCAsmBackend();
 
-  unsigned HasReliableSymbolDifference : 1;
+  unsigned HasDataInCodeSupport : 1;
 
 public:
   virtual ~MCAsmBackend();
 
+  /// lifetime management
+  virtual void reset() {}
+
   /// 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;
 
   /// createELFObjectTargetWriter - Create a new ELFObjectTargetWriter to enable
   /// non-standard ELFObjectWriters.
-  virtual  MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
+  virtual MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
     llvm_unreachable("createELFObjectTargetWriter is not supported by asm "
                      "backend");
   }
 
-  /// 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;
-  }
+  /// hasDataInCodeSupport - Check whether this target implements data-in-code
+  /// markers. If not, data region directives will be ignored.
+  bool hasDataInCodeSupport() const { return HasDataInCodeSupport; }
 
   /// doesSectionRequireSymbols - Check whether the given section requires that
   /// all symbols (even temporaries) have symbol table entries.
@@ -94,16 +90,14 @@ public:
   virtual void processFixupValue(const MCAssembler &Asm,
                                  const MCAsmLayout &Layout,
                                  const MCFixup &Fixup, const MCFragment *DF,
-                                 MCValue &Target, uint64_t &Value,
+                                 const MCValue &Target, uint64_t &Value,
                                  bool &IsResolved) {}
 
-  /// @}
-
-  /// applyFixup - Apply the \arg Value for given \arg Fixup into the provided
+  /// applyFixup - Apply the \p Value for given \p 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, char *Data, unsigned DataSize,
-                          uint64_t Value) const = 0;
+                          uint64_t Value, bool IsPCRel) const = 0;
 
   /// @}
 
@@ -118,21 +112,27 @@ public:
 
   /// fixupNeedsRelaxation - Target specific predicate for whether a given
   /// fixup requires the associated instruction to be relaxed.
-  virtual bool fixupNeedsRelaxation(const MCFixup &Fixup,
-                                    uint64_t Value,
-                                    const MCInstFragment *DF,
+  virtual bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
+                                    const MCRelaxableFragment *DF,
                                     const MCAsmLayout &Layout) 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
+  /// \param Inst The instruction to relax, which may be the same as the
   /// output.
-  /// \parm Res [output] - On return, the relaxed instruction.
+  /// \param [out] Res On return, the relaxed instruction.
   virtual void relaxInstruction(const MCInst &Inst, MCInst &Res) const = 0;
 
   /// @}
 
+  /// getMinimumNopSize - Returns the minimum size of a nop in bytes on this
+  /// target. The assembler will use this to emit excess padding in situations
+  /// where the padding required for simple alignment would be less than the
+  /// minimum nop size.
+  ///
+  virtual unsigned getMinimumNopSize() const { return 1; }
+
   /// 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.
@@ -143,6 +143,12 @@ public:
   /// handleAssemblerFlag - Handle any target-specific assembler flags.
   /// By default, do nothing.
   virtual void handleAssemblerFlag(MCAssemblerFlag Flag) {}
+
+  /// \brief Generate the compact unwind encoding for the CFI instructions.
+  virtual uint32_t
+  generateCompactUnwindEncoding(ArrayRef<MCCFIInstruction>) const {
+    return 0;
+  }
 };
 
 } // End llvm namespace