llvm-6502/test/Transforms/RewriteStatepointsForGC/constants.ll
Sanjoy Das ead2d1fbe0 [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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237214 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-12 23:52:24 +00:00

61 lines
2.1 KiB
LLVM

; RUN: opt -S -rewrite-statepoints-for-gc %s | FileCheck %s
declare void @foo()
declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)
; constants don't get relocated.
define i8 @test() gc "statepoint-example" {
; CHECK-LABEL: @test
; CHECK: gc.statepoint
; CHECK-NEXT: load i8, i8 addrspace(1)* inttoptr (i64 15 to i8 addrspace(1)*)
entry:
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)
%res = load i8, i8 addrspace(1)* inttoptr (i64 15 to i8 addrspace(1)*)
ret i8 %res
}
; Mostly just here to show reasonable code test can come from.
define i8 @test2(i8 addrspace(1)* %p) gc "statepoint-example" {
; CHECK-LABEL: @test2
; CHECK: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: icmp
entry:
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)
%cmp = icmp eq i8 addrspace(1)* %p, null
br i1 %cmp, label %taken, label %not_taken
taken:
ret i8 0
not_taken:
%cmp2 = icmp ne i8 addrspace(1)* %p, null
br i1 %cmp2, label %taken, label %dead
dead:
; We see that dead can't be reached, but the optimizer might not. It's
; completely legal for it to exploit the fact that if dead executed, %p
; would have to equal null. This can produce intermediate states which
; look like that of test above, even if arbitrary constant addresses aren't
; legal in the source language
%addr = getelementptr i8, i8 addrspace(1)* %p, i32 15
%res = load i8, i8addrspace(1)* %addr
ret i8 %res
}
@G = addrspace(1) global i8 5
; Globals don't move and thus don't get relocated
define i8 @test3(i1 %always_true) gc "statepoint-example" {
; CHECK-LABEL: @test3
; CHECK: gc.statepoint
; CHECK-NEXT: load i8, i8 addrspace(1)* @G
entry:
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)
%res = load i8, i8 addrspace(1)* @G, align 1
ret i8 %res
}