dd70aef05a
…ndows x86_64 targets that use windows 64 prologue Windows x86_64 stack frame layout is currently not compatible with Swift's async extended frame, which reserves the slot right below RBP (RBP-8) for the async context pointer, as it doesn't account for the fact that a stack object in a win64 frame can be allocated at the same location. This can cause issues at runtime, for instance, Swift's TCA test code has functions that fail because of this issue, as they spill a value to that slack slot, which then gets overwritten by a store into address returned by the @llvm.swift.async.context.addr() intrinsic (that ends up being RBP - 8), leading to an incorrect value being used at a later point when that stack slot is being read from again. This change drops the use of async extended frame for windows x86_64 subtargets and instead uses the x32 based approach of allocating a separate stack slot for the stored async context pointer. Additionally, LLDB which is the primary consumer of the extended frame makes assumptions like checking for a saved previous frame pointer at the current frame pointer address, which is also incompatible with the windows x86_64 frame layout, as the previous frame pointer is not guaranteed to be stored at the current frame pointer address. Therefore the extended frame layout can be turned off to fix the current miscompile without introducing regression into LLDB for windows x86_64 as it already doesn't work correctly. I am still investigating what should be made for LLDB to support using an allocated stack slot to store the async frame context instead of being located at RBP - 8 for windows.
122 lines
3.1 KiB
LLVM
122 lines
3.1 KiB
LLVM
; RUN: llc -mtriple x86_64-unknown-windows-msvc %s -o - | FileCheck %s -check-prefix CHECK64
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; RUN: llc -mtriple i686-windows-msvc %s -o - | FileCheck %s -check-prefix CHECK32
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define void @simple(ptr swiftasync %context) "frame-pointer"="all" {
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ret void
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}
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; CHECK64-LABEL: simple:
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; CHECK64: pushq %rbp
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; CHECK64: pushq %rax
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; CHECK64: movq %rsp, %rbp
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; CHECK64: movq %r14, (%rbp)
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; CHECK64: addq $8, %rsp
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; CHECK64: popq %rbp
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; CHECK64: retq
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; CHECK32-LABEL: simple:
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; CHECK32: movl 8(%ebp), [[TMP:%.*]]
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; CHECK32: movl [[TMP]], {{.*}}(%ebp)
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define void @more_csrs(ptr swiftasync %context) "frame-pointer"="all" {
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call void asm sideeffect "", "~{r15}"()
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ret void
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}
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; CHECK64-LABEL: more_csrs:
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; CHECK64: pushq %rbp
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; CHECK64: .seh_pushreg %rbp
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; CHECK64: pushq %r15
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; CHECK64: .seh_pushreg %r15
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; CHECK64: pushq %rax
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; CHECK64: .seh_stackalloc 8
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; CHECK64: movq %rsp, %rbp
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; CHECK64: .seh_setframe %rbp, 0
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; CHECK64: .seh_endprologue
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; CHECK64: movq %r14, (%rbp)
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; [...]
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; CHECK64: addq $8, %rsp
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; CHECK64: popq %r15
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; CHECK64: popq %rbp
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; CHECK64: retq
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declare void @f(ptr)
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define void @locals(ptr swiftasync %context) "frame-pointer"="all" {
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%var = alloca i32, i32 10
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call void @f(ptr %var)
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ret void
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}
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; CHECK64-LABEL: locals:
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; CHECK64: pushq %rbp
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; CHECK64: .seh_pushreg %rbp
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; CHECK64: subq $80, %rsp
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; CHECK64: movq %r14, -8(%rbp)
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; CHECK64: leaq -48(%rbp), %rcx
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; CHECK64: callq f
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; CHECK64: addq $80, %rsp
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; CHECK64: popq %rbp
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; CHECK64: retq
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define void @use_input_context(ptr swiftasync %context, ptr %ptr) "frame-pointer"="all" {
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store ptr %context, ptr %ptr
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ret void
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}
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; CHECK64-LABEL: use_input_context:
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; CHECK64: movq %r14, (%rcx)
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declare ptr @llvm.swift.async.context.addr()
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define ptr @context_in_func() "frmae-pointer"="non-leaf" {
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%ptr = call ptr @llvm.swift.async.context.addr()
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ret ptr %ptr
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}
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; CHECK64-LABEL: context_in_func:
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; CHECK64: movq %rsp, %rax
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; CHECK32-LABEL: context_in_func:
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; CHECK32: movl %esp, %eax
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define void @write_frame_context(ptr swiftasync %context, ptr %new_context) "frame-pointer"="non-leaf" {
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%ptr = call ptr @llvm.swift.async.context.addr()
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store ptr %new_context, ptr %ptr
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ret void
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}
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; CHECK64-LABEL: write_frame_context:
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; CHECK64: movq %rcx, (%rsp)
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define void @simple_fp_elim(ptr swiftasync %context) "frame-pointer"="non-leaf" {
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ret void
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}
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; CHECK64-LABEL: simple_fp_elim:
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; CHECK64-NOT: btsq
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define void @manylocals_and_overwritten_context(ptr swiftasync %context, ptr %new_context) "frame-pointer"="all" {
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%ptr = call ptr @llvm.swift.async.context.addr()
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store ptr %new_context, ptr %ptr
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%var1 = alloca i64, i64 1
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call void @f(ptr %var1)
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%var2 = alloca i64, i64 16
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call void @f(ptr %var2)
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%ptr2 = call ptr @llvm.swift.async.context.addr()
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store ptr %new_context, ptr %ptr2
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ret void
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}
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; CHECK64-LABEL: manylocals_and_overwritten_context:
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; CHECK64: pushq %rbp
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; CHECK64: subq $184, %rsp
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; CHECK64: leaq 128(%rsp), %rbp
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; CHECK64: movq %rcx, %rsi
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; CHECK64: movq %rcx, 48(%rbp)
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; CHECK64: callq f
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; CHECK64: callq f
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; CHECK64: movq %rsi, 48(%rbp)
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