8e810dc7d9
When the code is built with -mbackchain, it is possible to retrieve the caller's frame and return addresses. GCC already can do this, add this support to Clang as well. Use RISCVTargetLowering and GCC's s390_return_addr_rtx() as inspiration. Add tests based on what GCC is emitting.
50 lines
1.1 KiB
LLVM
50 lines
1.1 KiB
LLVM
; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
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; The current function's frame address is the address of
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; the optional back chain slot.
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define ptr @fp0() nounwind {
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entry:
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; CHECK-LABEL: fp0:
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; CHECK: la %r2, 0(%r15)
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; CHECK: br %r14
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%0 = tail call ptr @llvm.frameaddress(i32 0)
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ret ptr %0
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}
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; Check that the frame address is correct in a presence
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; of a stack frame.
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define ptr @fp0f() nounwind {
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entry:
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; CHECK-LABEL: fp0f:
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; CHECK: aghi %r15, -168
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; CHECK: la %r2, 168(%r15)
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; CHECK: aghi %r15, 168
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; CHECK: br %r14
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%0 = alloca i64, align 8
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%1 = tail call ptr @llvm.frameaddress(i32 0)
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ret ptr %1
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}
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; Check the caller's frame address.
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define ptr @fpcaller() nounwind "backchain" {
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entry:
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; CHECK-LABEL: fpcaller:
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; CHECK: lg %r2, 0(%r15)
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; CHECK: br %r14
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%0 = tail call ptr @llvm.frameaddress(i32 1)
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ret ptr %0
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}
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; Check the caller's frame address.
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define ptr @fpcallercaller() nounwind "backchain" {
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entry:
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; CHECK-LABEL: fpcallercaller:
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; CHECK: lg %r1, 0(%r15)
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; CHECK: lg %r2, 0(%r1)
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; CHECK: br %r14
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%0 = tail call ptr @llvm.frameaddress(i32 2)
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ret ptr %0
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}
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declare ptr @llvm.frameaddress(i32) nounwind readnone
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