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, 1 insertions, 0 deletions

diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
index 99236bd24ea..aa7a968d50f 100644
--- a/llvm/lib/LTO/LTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -96,6 +96,7 @@ void LTOCodeGenerator::initializeLTOPasses() {
   initializeConstantMergePass(R);
   initializeDAHPass(R);
   initializeInstCombinerPass(R);
+  initializeJumpInstrTablesPass(R);
   initializeSimpleInlinerPass(R);
   initializePruneEHPass(R);
   initializeGlobalDCEPass(R);