test/CodeGen/X86/statepoint-stack-usage.ll

; RUN: llc -verify-machineinstrs -stack-symbol-ordering=0 < %s | FileCheck %s

target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"

; This test is checking to make sure that we reuse the same stack slots
; for GC values spilled over two different call sites.  Since the order
; of GC arguments differ, niave lowering code would insert loads and 
; stores to rearrange items on the stack.  We need to make sure (for
; performance) that this doesn't happen.
define i32 @back_to_back_calls(ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c) #1 gc "statepoint-example" {
; CHECK-LABEL: back_to_back_calls
; The exact stores don't matter, but there need to be three stack slots created
; CHECK-DAG: movq	%rdi, {{[0-9]*}}(%rsp)
; CHECK-DAG: movq	%rdx, {{[0-9]*}}(%rsp)
; CHECK-DAG: movq	%rsi, {{[0-9]*}}(%rsp)
; There should be no more than three moves
; CHECK-NOT: movq
  %safepoint_token = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c), "deopt" (i32 0, i32 -1, i32 0, i32 0, i32 0)]
  %a1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 0)
  %b1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 1)
  %c1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 2)
; CHECK: callq
; This is the key check.  There should NOT be any memory moves here
; CHECK-NOT: movq
  %safepoint_token2 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %c1, ptr addrspace(1) %b1, ptr addrspace(1) %a1), "deopt" (i32 0, i32 -1, i32 0, i32 0, i32 0)]
  %a2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 2)
  %b2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 1)
  %c2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 0)
; CHECK: callq
  ret i32 1
}

; This test simply checks that minor changes in vm state don't prevent slots
; being reused for gc values.  
define i32 @reserve_first(ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c) #1 gc "statepoint-example" {
; CHECK-LABEL: reserve_first
; The exact stores don't matter, but there need to be three stack slots created
; CHECK-DAG: movq	%rdi, {{[0-9]*}}(%rsp)
; CHECK-DAG: movq	%rdx, {{[0-9]*}}(%rsp)
; CHECK-DAG: movq	%rsi, {{[0-9]*}}(%rsp)
  %safepoint_token = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c), "deopt" (i32 0, i32 -1, i32 0, i32 0, i32 0)]
  %a1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 0)
  %b1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 1)
  %c1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 2)
; CHECK: callq
; This is the key check.  There should NOT be any memory moves here
; CHECK-NOT: movq
  %safepoint_token2 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %c1, ptr addrspace(1) %b1, ptr addrspace(1) %a1), "deopt" (ptr addrspace(1) %a1, i32 0, ptr addrspace(1) %c1, i32 0, i32 0)]
  %a2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 2)
  %b2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 1)
  %c2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 0)
; CHECK: callq
  ret i32 1
}

; Check that we reuse the same stack slot across multiple calls.  The use of
; more than two calls here is critical.  We've had a bug which allowed reuse
; exactly once which went undetected for a long time.
define i32 @back_to_back_deopt(i32 %a, i32 %b, i32 %c) #1 
  gc "statepoint-example" {
; CHECK-LABEL: back_to_back_deopt
; The exact stores don't matter, but there need to be three stack slots created
; CHECK-DAG: movl	%edi, 12(%rsp)
; CHECK-DAG: movl	%esi, 8(%rsp)
; CHECK-DAG: movl	%edx, 4(%rsp)
; CHECK: callq
; CHECK-DAG: movl	%r14d, 12(%rsp)
; CHECK-DAG: movl	%ebp, 8(%rsp)
; CHECK-DAG: movl	%ebx, 4(%rsp)
; CHECK: callq
; CHECK-DAG: movl	%r14d, 12(%rsp)
; CHECK-DAG: movl	%ebp, 8(%rsp)
; CHECK-DAG: movl	%ebx, 4(%rsp)
; CHECK: callq
; CHECK-DAG: movl	%r14d, 12(%rsp)
; CHECK-DAG: movl	%ebp, 8(%rsp)
; CHECK-DAG: movl	%ebx, 4(%rsp)
; CHECK: callq
  call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["deopt" (i32 %a, i32 %b, i32 %c)]
call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["deopt" (i32 %a, i32 %b, i32 %c)]
call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["deopt" (i32 %a, i32 %b, i32 %c)]
call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["deopt" (i32 %a, i32 %b, i32 %c)]
  ret i32 1
}

; Test that stack slots are reused for invokes
define i32 @back_to_back_invokes(ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c) #1 gc "statepoint-example" personality ptr @"personality_function" {
; CHECK-LABEL: back_to_back_invokes
entry:
  ; The exact stores don't matter, but there need to be three stack slots created
  ; CHECK-DAG: movq	%rdi, {{[0-9]*}}(%rsp)
  ; CHECK-DAG: movq	%rdx, {{[0-9]*}}(%rsp)
  ; CHECK-DAG: movq	%rsi, {{[0-9]*}}(%rsp)
  ; CHECK: callq
  %safepoint_token = invoke token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %a, ptr addrspace(1) %b, ptr addrspace(1) %c), "deopt" (i32 0, i32 -1, i32 0, i32 0, i32 0)]
                   to label %normal_return unwind label %exceptional_return

normal_return:
  %a1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 0)
  %b1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 1)
  %c1 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token, i32 0, i32 2)
  ; Should work even through bitcasts
  ; This is the key check.  There should NOT be any memory moves here
  ; CHECK-NOT: movq
  ; CHECK: callq
  %safepoint_token2 = invoke token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 0, i32 0, ptr elementtype(void ()) undef, i32 0, i32 0, i32 0, i32 0) ["gc-live" (ptr addrspace(1) %c1, ptr addrspace(1) %b1, ptr addrspace(1) %a1), "deopt" (i32 0, i32 -1, i32 0, i32 0, i32 0)]
                    to label %normal_return2 unwind label %exceptional_return2

normal_return2:
  %a2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 2)
  %b2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 1)
  %c2 = tail call coldcc ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token %safepoint_token2, i32 0, i32 0)
  ret i32 1

exceptional_return:
  %landing_pad = landingpad { ptr, i32 }
          cleanup
  ret i32 0

exceptional_return2:
  %landing_pad2 = landingpad { ptr, i32 }
          cleanup
  ret i32 0
}

; Function Attrs: nounwind
declare ptr addrspace(1) @llvm.experimental.gc.relocate.p1(token, i32, i32) #3

declare token @llvm.experimental.gc.statepoint.p0(i64, i32, ptr, i32, i32, ...)

declare i32 @"personality_function"()

attributes #1 = { uwtable }