llvm-6502/test/CodeGen/PowerPC/sjlj.ll
Hal Finkel 7ee74a663a Implement builtin_{setjmp/longjmp} on PPC
This implements SJLJ lowering on PPC, making the Clang functions
__builtin_{setjmp/longjmp} functional on PPC platforms. The implementation
strategy is similar to that on X86, with the exception that a branch-and-link
variant is used to get the right jump address. Credit goes to Bill Schmidt for
suggesting the use of the unconditional bcl form (instead of the regular bl
instruction) to limit return-address-cache pollution.

Benchmarking the speed at -O3 of:

static jmp_buf env_sigill;

void foo() {
                __builtin_longjmp(env_sigill,1);
}

main() {
	...

        for (int i = 0; i < c; ++i) {
                if (__builtin_setjmp(env_sigill)) {
                        goto done;
                } else {
                        foo();
                }

done:;
        }

	...
}

vs. the same code using the libc setjmp/longjmp functions on a P7 shows that
this builtin implementation is ~4x faster with Altivec enabled and ~7.25x
faster with Altivec disabled. This comparison is somewhat unfair because the
libc version must also save/restore the VSX registers which we don't yet
support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177666 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-21 21:37:52 +00:00

109 lines
3.3 KiB
LLVM

; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 | FileCheck %s
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2 | FileCheck -check-prefix=CHECK-NOAV %s
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
%struct.__jmp_buf_tag = type { [64 x i64], i32, %struct.__sigset_t, [8 x i8] }
%struct.__sigset_t = type { [16 x i64] }
@env_sigill = internal global [1 x %struct.__jmp_buf_tag] zeroinitializer, align 16
define void @foo() #0 {
entry:
call void @llvm.eh.sjlj.longjmp(i8* bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8*))
unreachable
; CHECK: @foo
; CHECK: addis [[REG:[0-9]+]], 2, env_sigill@toc@ha
; CHECK: addi [[REG]], [[REG]], env_sigill@toc@l
; CHECK: ld 31, 0([[REG]])
; CHECK: ld [[REG2:[0-9]+]], 8([[REG]])
; CHECK: ld 1, 16([[REG]])
; CHECK: mtctr [[REG2]]
; CHECK: ld 2, 24([[REG]])
; CHECK: bctr
return: ; No predecessors!
ret void
}
declare void @llvm.eh.sjlj.longjmp(i8*) #1
define signext i32 @main() #0 {
entry:
%retval = alloca i32, align 4
store i32 0, i32* %retval
%0 = call i8* @llvm.frameaddress(i32 0)
store i8* %0, i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**)
%1 = call i8* @llvm.stacksave()
store i8* %1, i8** getelementptr (i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**), i32 2)
%2 = call i32 @llvm.eh.sjlj.setjmp(i8* bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8*))
%tobool = icmp ne i32 %2, 0
br i1 %tobool, label %if.then, label %if.else
if.then: ; preds = %entry
store i32 1, i32* %retval
br label %return
if.else: ; preds = %entry
call void @foo()
br label %if.end
if.end: ; preds = %if.else
store i32 0, i32* %retval
br label %return
return: ; preds = %if.end, %if.then
%3 = load i32* %retval
ret i32 %3
; CHECK: @main
; CHECK: std
; CHECK: stfd
; CHECK: stvx
; CHECK: addis [[REG:[0-9]+]], 2, env_sigill@toc@ha
; CHECK: std 31, env_sigill@toc@l([[REG]])
; CHECK: addi [[REG]], [[REG]], env_sigill@toc@l
; CHECK: std [[REG]], [[OFF:[0-9]+]](31) # 8-byte Folded Spill
; CHECK: std 1, 16([[REG]])
; CHECK: std 2, 24([[REG]])
; CHECK: bcl 20, 31, .LBB1_1
; CHECK: li 3, 1
; CHECK: #EH_SjLj_Setup .LBB1_1
; CHECK: b .LBB1_2
; CHECK: .LBB1_1:
; CHECK: mflr [[REGL:[0-9]+]]
; CHECK: ld [[REG2:[0-9]+]], [[OFF]](31) # 8-byte Folded Reload
; CHECK: std [[REGL]], 8([[REG2]])
; CHECK: li 3, 0
; CHECK: .LBB1_2:
; CHECK: lfd
; CHECK: lvx
; CHECK: ld
; CHECK: blr
; CHECK-NOAV: @main
; CHECK-NOAV-NOT: stvx
; CHECK-NOAV: bcl
; CHECK-NOAV: mflr
; CHECK-NOAV: bl foo
; CHECK-NOAV-NOT: lvx
; CHECK-NOAV: blr
}
declare i8* @llvm.frameaddress(i32) #2
declare i8* @llvm.stacksave() #3
declare i32 @llvm.eh.sjlj.setjmp(i8*) #3
attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { noreturn nounwind }
attributes #2 = { nounwind readnone }
attributes #3 = { nounwind }