Replace PROLOG_LABEL with a new CFI_INSTRUCTION.

The old system was fairly convoluted:
* A temporary label was created.
* A single PROLOG_LABEL was created with it.
* A few MCCFIInstructions were created with the same label.

The semantics were that the cfi instructions were mapped to the PROLOG_LABEL
via the temporary label. The output position was that of the PROLOG_LABEL.
The temporary label itself was used only for doing the mapping.

The new CFI_INSTRUCTION has a 1:1 mapping to MCCFIInstructions and points to
one by holding an index into the CFI instructions of this function.

I did consider removing MMI.getFrameInstructions completelly and having
CFI_INSTRUCTION own a MCCFIInstruction, but MCCFIInstructions have non
trivial constructors and destructors and are somewhat big, so the this setup
is probably better.

The net result is that we don't create temporary labels that are never used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203204 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 2 insertions, 2 deletions

diff --git a/include/llvm/Target/Target.td b/include/llvm/Target/Target.td
index 55b65d0135..59c0a6abe1 100644
--- a/include/llvm/Target/Target.td
+++ b/include/llvm/Target/Target.td
@@ -714,7 +714,7 @@ def INLINEASM : Instruction {
   let AsmString = "";
   let neverHasSideEffects = 1;  // Note side effect is encoded in an operand.
 }
-def PROLOG_LABEL : Instruction {
+def CFI_INSTRUCTION : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
diff --git a/include/llvm/Target/TargetOpcodes.h b/include/llvm/Target/TargetOpcodes.h
index d6225a4bc0..abb3ecacae 100644
--- a/include/llvm/Target/TargetOpcodes.h
+++ b/include/llvm/Target/TargetOpcodes.h
@@ -25,7 +25,7 @@ namespace TargetOpcode {
 enum {
   PHI = 0,
   INLINEASM = 1,
-  PROLOG_LABEL = 2,
+  CFI_INSTRUCTION = 2,
   EH_LABEL = 3,
   GC_LABEL = 4,