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llvm-mirror/test/CodeGen/X86/xchg-nofold.ll
Diogo N. Sampaio 82cb0e3bb0 [FIX] Forces shrink wrapping to consider any memory access as aliasing with the stack
Summary:
Relate bug: https://bugs.llvm.org/show_bug.cgi?id=37472

The shrink wrapping pass prematurally restores the stack, at a point where the stack might still be accessed.
Taking an exception can cause the stack to be corrupted.

As a first approach, this patch is overly conservative, assuming that any instruction that may load or store could access
the stack.

Reviewers: dmgreen, qcolombet

Reviewed By: qcolombet

Subscribers: simpal01, efriedma, eli.friedman, javed.absar, llvm-commits, eugenis, chill, carwil, thegameg

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63152

llvm-svn: 363265
2019-06-13 13:56:19 +00:00

62 lines
2.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=x86_64-linux-gnu < %s | FileCheck %s
%"struct.std::atomic" = type { %"struct.std::atomic_bool" }
%"struct.std::atomic_bool" = type { %"struct.std::__atomic_base" }
%"struct.std::__atomic_base" = type { i8 }
; CHECK-LABEL: _Z3fooRSt6atomicIbEb
define zeroext i1 @_Z3fooRSt6atomicIbEb(%"struct.std::atomic"* nocapture dereferenceable(1) %a, i1 returned zeroext %b) nounwind {
; CHECK-LABEL: _Z3fooRSt6atomicIbEb:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: pushq %rax
; CHECK-NEXT: movl %esi, %eax
; CHECK-NEXT: movq %rdi, %rcx
; CHECK-NEXT: shrq $3, %rcx
; CHECK-NEXT: movb 2147450880(%rcx), %cl
; CHECK-NEXT: testb %cl, %cl
; CHECK-NEXT: je .LBB0_3
; CHECK-NEXT: # %bb.1:
; CHECK-NEXT: movl %edi, %edx
; CHECK-NEXT: andb $7, %dl
; CHECK-NEXT: cmpb %cl, %dl
; CHECK-NEXT: jge .LBB0_2
; CHECK-NEXT: .LBB0_3:
; CHECK-NEXT: movl %eax, %ecx
; CHECK-NEXT: xchgb %cl, (%rdi)
; CHECK-NEXT: # kill: def $al killed $al killed $eax
; CHECK-NEXT: popq %rcx
; CHECK-NEXT: retq
; CHECK-NEXT: .LBB0_2:
; CHECK-NEXT: callq __asan_report_store1
; CHECK-NEXT: #APP
; CHECK-NEXT: #NO_APP
entry:
%frombool.i.i = zext i1 %b to i8
%_M_i.i.i = getelementptr inbounds %"struct.std::atomic", %"struct.std::atomic"* %a, i64 0, i32 0, i32 0, i32 0
%0 = ptrtoint i8* %_M_i.i.i to i64
%1 = lshr i64 %0, 3
%2 = add i64 %1, 2147450880
%3 = inttoptr i64 %2 to i8*
%4 = load i8, i8* %3
%5 = icmp ne i8 %4, 0
br i1 %5, label %6, label %11
; <label>:6: ; preds = %entry
%7 = and i64 %0, 7
%8 = trunc i64 %7 to i8
%9 = icmp sge i8 %8, %4
br i1 %9, label %10, label %11
; <label>:10: ; preds = %6
call void @__asan_report_store1(i64 %0)
call void asm sideeffect "", ""()
unreachable
; <label>:11: ; preds = %6, %entry
store atomic i8 %frombool.i.i, i8* %_M_i.i.i seq_cst, align 1
ret i1 %b
}
declare void @__asan_report_store1(i64)