MC: Add TargetAsmBackend::MayNeedRelaxation, for checking whether a particular instruction + fixups might need relaxation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99249 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 15 insertions, 0 deletions

diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index d7f1acea35..d14122bf74 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -679,6 +679,10 @@ private:
   bool FixupNeedsRelaxation(const MCAsmFixup &Fixup, const MCFragment *DF,
                             const MCAsmLayout &Layout) const;
 
+  /// Check whether the given fragment needs relaxation.
+  bool FragmentNeedsRelaxation(const MCInstFragment *IF,
+                               const MCAsmLayout &Layout) const;
+
   /// LayoutSection - Assign offsets and sizes to the fragments in the section
   /// \arg SD, and update the section size. The section file offset should
   /// already have been computed.
diff --git a/include/llvm/Target/TargetAsmBackend.h b/include/llvm/Target/TargetAsmBackend.h
index 16f33c32f4..f350ecc410 100644
--- a/include/llvm/Target/TargetAsmBackend.h
+++ b/include/llvm/Target/TargetAsmBackend.h
@@ -19,6 +19,8 @@ class MCInst;
 class MCInstFragment;
 class MCObjectWriter;
 class MCSection;
+template<typename T>
+class SmallVectorImpl;
 class Target;
 class raw_ostream;
 
@@ -98,6 +100,15 @@ public:
   virtual void ApplyFixup(const MCAsmFixup &Fixup, MCDataFragment &Fragment,
                           uint64_t Value) const = 0;
 
+  /// MayNeedRelaxation - Check whether the given instruction may need
+  /// relaxation.
+  ///
+  /// \arg Inst - The instruction to test.
+  /// \arg Fixups - The actual fixups this instruction encoded to, for potential
+  /// use by the target backend.
+  virtual bool MayNeedRelaxation(const MCInst &Inst,
+                           const SmallVectorImpl<MCAsmFixup> &Fixups) const = 0;
+
   /// RelaxInstruction - Relax the instruction in the given fragment to the next
   /// wider instruction.
   virtual void RelaxInstruction(const MCInstFragment *IF,