[Statepoints] Support for "patchable" statepoints.

Summary:
This change adds two new parameters to the statepoint intrinsic, `i64 id`
and `i32 num_patch_bytes`.  `id` gets propagated to the ID field
in the generated StackMap section.  If the `num_patch_bytes` is
non-zero then the statepoint is lowered to `num_patch_bytes` bytes of
nops instead of a call (the spill and reload code remains unchanged).
A non-zero `num_patch_bytes` is useful in situations where a language
runtime requires complete control over how a call is lowered.

This change brings statepoints one step closer to patchpoints.  With
some additional work (that is not part of this patch) it should be
possible to get rid of `TargetOpcode::STATEPOINT` altogether.

PlaceSafepoints generates `statepoint` wrappers with `id` set to
`0xABCDEF00` (the old default value for the ID reported in the stackmap)
and `num_patch_bytes` set to `0`.  This can be made more sophisticated
later.

Reviewers: reames, pgavlin, swaroop.sridhar, AndyAyers

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9546

llvm-svn: 237214

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/test/Transforms/RewriteStatepointsForGC/preprocess.ll b/llvm/test/Transforms/RewriteStatepointsForGC/preprocess.ll
index 39567b12227..60215310af0 100644
--- a/llvm/test/Transforms/RewriteStatepointsForGC/preprocess.ll
+++ b/llvm/test/Transforms/RewriteStatepointsForGC/preprocess.ll
@@ -17,7 +17,7 @@ next:
 ; CHECK-NEXT: @consume(i64 addrspace(1)* %obj.relocated.casted)
 ; CHECK-NEXT: @consume(i64 addrspace(1)* %obj.relocated.casted)
   %obj2 = phi i64 addrspace(1)* [ %obj, %entry ]
-  call i32 (void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()* @foo, i32 0, i32 0, i32 0, i32 0)
+  call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0)
   call void (...) @consume(i64 addrspace(1)* %obj2)
   call void (...) @consume(i64 addrspace(1)* %obj)
   ret void
@@ -33,7 +33,7 @@ define void @test7() gc "statepoint-example" {
 
 unreached:
   %obj = phi i64 addrspace(1)* [null, %unreached]
-  call i32 (void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()* @foo, i32 0, i32 0, i32 0, i32 0)
+  call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0)
   call void (...) @consume(i64 addrspace(1)* %obj)
   br label %unreached
 }
@@ -46,7 +46,7 @@ define void @test8() gc "statepoint-example" {
   ret void
 
 unreached:
-  invoke i32 (void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()* @foo, i32 0, i32 0, i32 0, i32 0)
+  invoke i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0)
           to label %normal_return unwind label %exceptional_return
 
 normal_return:                                    ; preds = %entry
@@ -62,5 +62,4 @@ declare void @foo()
 ; Bound the last check-not
 ; CHECK-LABEL: @foo
 
-declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()*, i32, i32, ...)
-
+declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)