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c68bb48704
It is intended to fix PR11468. Old prologue and epilogue looked like this: push %rbp mov %rsp, %rbp and $alignment, %rsp push %r14 push %r15 ... pop %r15 pop %r14 mov %rbp, %rsp pop %rbp The problem was to reference the locations of callee-saved registers in exception handling: locations of callee-saved had to be re-calculated regarding the stack alignment operation. It would take some effort to implement this in LLVM, as currently MachineLocation can only have the form "Register + Offset". Funciton prologue and epilogue are now changed to: push %rbp mov %rsp, %rbp push %14 push %15 and $alignment, %rsp ... lea -$size_of_saved_registers(%rbp), %rsp pop %r15 pop %r14 pop %rbp Reviewed by Chad Rosier. llvm-svn: 160248
71 lines
2.1 KiB
LLVM
71 lines
2.1 KiB
LLVM
; This test is attempting to detect when we request forced re-alignment of the
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; stack to an alignment greater than would be available due to the ABI. We
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; arbitrarily force alignment up to 32-bytes for i386 hoping that this will
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; exceed any ABI provisions.
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;
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; RUN: llc < %s -force-align-stack -stack-alignment=32 | FileCheck %s
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target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
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target triple = "i386-unknown-linux-gnu"
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define i32 @f(i8* %p) nounwind {
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entry:
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%0 = load i8* %p
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%conv = sext i8 %0 to i32
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ret i32 %conv
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}
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define i64 @g(i32 %i) nounwind {
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; CHECK: g:
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; CHECK: pushl %ebp
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; CHECK-NEXT: movl %esp, %ebp
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; CHECK-NEXT: pushl
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; CHECK-NEXT: pushl
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; CHECK-NEXT: andl $-32, %esp
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; CHECK-NEXT: subl $32, %esp
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;
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; Now setup the base pointer (%ebx).
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; CHECK-NEXT: movl %esp, %ebx
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; CHECK-NOT: {{[^ ,]*}}, %esp
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;
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; The next adjustment of the stack is due to the alloca.
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; CHECK: movl %{{...}}, %esp
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; CHECK-NOT: {{[^ ,]*}}, %esp
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;
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; Next we set up the memset call, and then undo it.
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; CHECK: subl $32, %esp
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; CHECK-NOT: {{[^ ,]*}}, %esp
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; CHECK: calll memset
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; CHECK-NEXT: addl $32, %esp
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; CHECK-NOT: {{[^ ,]*}}, %esp
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;
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; Next we set up the call to 'f'.
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; CHECK: subl $32, %esp
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; CHECK-NOT: {{[^ ,]*}}, %esp
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; CHECK: calll f
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; CHECK-NEXT: addl $32, %esp
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; CHECK-NOT: {{[^ ,]*}}, %esp
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;
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; Restore %esp from %ebp (frame pointer) and subtract the size of
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; zone with callee-saved registers to pop them.
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; This is the state prior to stack realignment and the allocation of VLAs.
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; CHECK-NOT: popl
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; CHECK: leal -8(%ebp), %esp
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; CHECK-NEXT: popl
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; CHECK-NEXT: popl
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; CHECK-NEXT: popl %ebp
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; CHECK-NEXT: ret
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entry:
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br label %if.then
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if.then:
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%0 = alloca i8, i32 %i
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call void @llvm.memset.p0i8.i32(i8* %0, i8 0, i32 %i, i32 1, i1 false)
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%call = call i32 @f(i8* %0)
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%conv = sext i32 %call to i64
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ret i64 %conv
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}
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declare void @llvm.memset.p0i8.i32(i8*, i8, i32, i32, i1) nounwind
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