Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.

It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.

This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.

llvm-svn: 210280

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.h b/llvm/lib/Target/ARM/ARMBaseInstrInfo.h
index 4b3e74023ac..891e3ee176a 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.h
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.h
@@ -229,6 +229,13 @@ public:
                                       const TargetRegisterInfo*) const override;
   void breakPartialRegDependency(MachineBasicBlock::iterator, unsigned,
                                  const TargetRegisterInfo *TRI) const override;
+
+  void
+  getUnconditionalBranch(MCInst &Branch,
+                         const MCSymbolRefExpr *BranchTarget) const override;
+
+  void getTrap(MCInst &MI) const override;
+
   /// Get the number of addresses by LDM or VLDM or zero for unknown.
   unsigned getNumLDMAddresses(const MachineInstr *MI) const;