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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210280 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 0 deletions

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 7b018a6b65..41d1f066b5 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -549,6 +549,8 @@ static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
     return Attribute::InlineHint;
   case bitc::ATTR_KIND_IN_REG:
     return Attribute::InReg;
+  case bitc::ATTR_KIND_JUMP_TABLE:
+    return Attribute::JumpTable;
   case bitc::ATTR_KIND_MIN_SIZE:
     return Attribute::MinSize;
   case bitc::ATTR_KIND_NAKED:
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index dddcbc6f7e..55ed8ceb51 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -177,6 +177,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
     return bitc::ATTR_KIND_INLINE_HINT;
   case Attribute::InReg:
     return bitc::ATTR_KIND_IN_REG;
+  case Attribute::JumpTable:
+    return bitc::ATTR_KIND_JUMP_TABLE;
   case Attribute::MinSize:
     return bitc::ATTR_KIND_MIN_SIZE;
   case Attribute::Naked: