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0f8f086e21
This prevents us from running out of registers in the backend. Introducing stack malloc calls prevents the backend from recognizing the inline asm operands as stack objects. When the backend recognizes a stack object, it doesn't need to materialize the address of the memory in a physical register. Instead it generates a simple SP-based memory operand. Introducing a stack malloc forces the backend to find a free register for every memory operand. 32-bit x86 simply doesn't have enough registers for this to succeed in most cases. Reviewers: kcc, samsonov Differential Revision: http://reviews.llvm.org/D8790 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233979 91177308-0d34-0410-b5e6-96231b3b80d8
54 lines
2.0 KiB
LLVM
54 lines
2.0 KiB
LLVM
; RUN: opt < %s -asan -S -o %t.ll
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; RUN: FileCheck %s < %t.ll
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; RUN: llc < %t.ll | FileCheck %s --check-prefix=ASM
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target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-S32"
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target triple = "i386-pc-windows-msvc"
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define void @MyCPUID(i32 %fxn, i32* %out) sanitize_address {
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%fxn.ptr = alloca i32
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%a.ptr = alloca i32
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%b.ptr = alloca i32
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%c.ptr = alloca i32
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%d.ptr = alloca i32
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store i32 %fxn, i32* %fxn.ptr
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call void asm sideeffect inteldialect "xchg ebx, esi\0A\09mov eax, dword ptr $4\0A\09cpuid\0A\09mov dword ptr $0, eax\0A\09mov dword ptr $1, ebx\0A\09mov dword ptr $2, ecx\0A\09mov dword ptr $3, edx\0A\09xchg ebx, esi", "=*m,=*m,=*m,=*m,*m,~{eax},~{ebx},~{ecx},~{edx},~{esi},~{dirflag},~{fpsr},~{flags}"(i32* %a.ptr, i32* %b.ptr, i32* %c.ptr, i32* %d.ptr, i32* %fxn.ptr)
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%a = load i32, i32* %a.ptr
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%a.out = getelementptr inbounds i32, i32* %out, i32 0
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store i32 %a, i32* %a.out
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%b = load i32, i32* %b.ptr
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%b.out = getelementptr inbounds i32, i32* %out, i32 1
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store i32 %b, i32* %b.out
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%c = load i32, i32* %c.ptr
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%c.out = getelementptr inbounds i32, i32* %out, i32 2
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store i32 %c, i32* %c.out
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%d = load i32, i32* %d.ptr
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%d.out = getelementptr inbounds i32, i32* %out, i32 3
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store i32 %d, i32* %d.out
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ret void
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}
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; We used to introduce stack mallocs for UAR detection, but that makes LLVM run
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; out of registers on 32-bit platforms. Therefore, we don't do stack malloc on
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; such functions.
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; CHECK-LABEL: define void @MyCPUID(i32 %fxn, i32* %out)
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; CHECK: %MyAlloca = alloca [96 x i8], align 32
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; CHECK-NOT: call {{.*}} @__asan_stack_malloc
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; The code generator should recognize that all operands are just stack memory.
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; This is important with MS inline asm where operand lists are implicit and all
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; local variables can be referenced freely.
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; ASM-LABEL: MyCPUID:
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; ASM: cpuid
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; ASM-NEXT: movl %eax, {{[0-9]+}}(%esp)
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; ASM-NEXT: movl %ebx, {{[0-9]+}}(%esp)
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; ASM-NEXT: movl %ecx, {{[0-9]+}}(%esp)
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; ASM-NEXT: movl %edx, {{[0-9]+}}(%esp)
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