Pat Gavlin 5c7f7462e4 Extend the statepoint intrinsic to allow statepoints to be marked as transitions from GC-aware code to code that is not GC-aware.
This changes the shape of the statepoint intrinsic from:

  @llvm.experimental.gc.statepoint(anyptr target, i32 # call args, i32 unused, ...call args, i32 # deopt args, ...deopt args, ...gc args)

to:

  @llvm.experimental.gc.statepoint(anyptr target, i32 # call args, i32 flags, ...call args, i32 # transition args, ...transition args, i32 # deopt args, ...deopt args, ...gc args)

This extension offers the backend the opportunity to insert (somewhat) arbitrary code to manage the transition from GC-aware code to code that is not GC-aware and back.

In order to support the injection of transition code, this extension wraps the STATEPOINT ISD node generated by the usual lowering lowering with two additional nodes: GC_TRANSITION_START and GC_TRANSITION_END. The transition arguments that were passed passed to the intrinsic (if any) are lowered and provided as operands to these nodes and may be used by the backend during code generation.

Eventually, the lowering of the GC_TRANSITION_{START,END} nodes should be informed by the GC strategy in use for the function containing the intrinsic call; for now, these nodes are instead replaced with no-ops.

Differential Revision: http://reviews.llvm.org/D9501

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236888 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-08 18:07:42 +00:00

95 lines
2.2 KiB
LLVM

; RUN: opt %s -S -place-safepoints | FileCheck %s
; Do we insert a simple entry safepoint?
define void @test_entry() gc "statepoint-example" {
; CHECK-LABEL: @test_entry
entry:
; CHECK-LABEL: entry
; CHECK: statepoint
ret void
}
; On a non-gc function, we should NOT get an entry safepoint
define void @test_negative() {
; CHECK-LABEL: @test_negative
entry:
; CHECK-NOT: statepoint
ret void
}
; Do we insert a backedge safepoint in a statically
; infinite loop?
define void @test_backedge() gc "statepoint-example" {
; CHECK-LABEL: test_backedge
entry:
; CHECK-LABEL: entry
; This statepoint is technically not required, but we don't exploit that yet.
; CHECK: statepoint
br label %other
; CHECK-LABEL: other
; CHECK: statepoint
other:
call void undef()
br label %other
}
; Check that we remove an unreachable block rather than trying
; to insert a backedge safepoint
define void @test_unreachable() gc "statepoint-example" {
; CHECK-LABEL: test_unreachable
entry:
; CHECK-LABEL: entry
; CHECK: statepoint
ret void
; CHECK-NOT: other
; CHECK-NOT: statepoint
other:
br label %other
}
declare void @foo()
; Do we turn a call into it's own statepoint
define void @test_simple_call() gc "statepoint-example" {
; CHECK-LABEL: test_simple_call
entry:
br label %other
other:
; CHECK-LABEL: other
; CHECK: statepoint
; CHECK-NOT: gc.result
call void @foo()
ret void
}
declare zeroext i1 @i1_return_i1(i1)
define i1 @test_call_with_result() gc "statepoint-example" {
; CHECK-LABEL: test_call_with_result
; This is checking that a statepoint_poll + statepoint + result is
; inserted for a function that takes 1 argument.
; CHECK: gc.statepoint.p0f_isVoidf
; CHECK: gc.statepoint.p0f_i1i1f
; CHECK: (i1 (i1)* @i1_return_i1, i32 1, i32 0, i1 false, i32 0, i32 0)
; CHECK: %call12 = call i1 @llvm.experimental.gc.result.i1
entry:
%call1 = tail call i1 (i1) @i1_return_i1(i1 false)
ret i1 %call1
}
; This function is inlined when inserting a poll. To avoid recursive
; issues, make sure we don't place safepoints in it.
declare void @do_safepoint()
define void @gc.safepoint_poll() {
; CHECK-LABEL: gc.safepoint_poll
; CHECK-LABEL: entry
; CHECK-NEXT: do_safepoint
; CHECK-NEXT: ret void
entry:
call void @do_safepoint()
ret void
}