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3a75cd4bf9
With this change, ideally IR pass can always generate llvm.stackguard call to get the stack guard; but for now there are still IR form stack guard customizations around (see getIRStackGuard()). Future SSP customization should go through LOAD_STACK_GUARD. There is a behavior change: stack guard values are not CSEed anymore, since we should never reuse the value in case that it has been spilled (and corrupted). See ssp-guard-spill.ll. This also cause the change of stack size and codegen in X86 and AArch64 test cases. Ideally we'd like to know if the guard created in llvm.stackprotector() gets spilled or not. If the value is spilled, discard the value and reload stack guard; otherwise reuse the value. This can be done by teaching register allocator to know how to rematerialize LOAD_STACK_GUARD and force a rematerialization (which seems hard), or check for spilling in expandPostRAPseudo. It only makes sense when the stack guard is a global variable, which requires more instructions to load. Anyway, this seems to go out of the scope of the current patch. llvm-svn: 266806
47 lines
1.2 KiB
LLVM
47 lines
1.2 KiB
LLVM
; RUN: llc -o - %s | FileCheck %s
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx"
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; selectiondag stack protector uses a GuardReg which the fast-isel stack
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; protection code did not but the state was not reset properly.
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; The optnone attribute on @bar forces fast-isel.
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; CHECK-LABEL: foo:
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; CHECK: movq ___stack_chk_guard@GOTPCREL(%rip), %rax
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; CHECK: movq ___stack_chk_guard@GOTPCREL(%rip), %rax
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define void @foo() #0 {
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entry:
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%_tags = alloca [3 x i32], align 4
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ret void
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}
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; CHECK-LABEL: bar:
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; CHECK: movq ___stack_chk_guard@GOTPCREL(%rip), %{{r.x}}
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; CHECK-DAG: movq ___stack_chk_guard@GOTPCREL(%rip), %[[GUARD:r.x]]
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; CHECK-DAG: movq {{[0-9]+}}(%rsp), %[[CANARY:r.x]]
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; CHECK: subq %[[CANARY]], %[[GUARD]]
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define void @bar() #1 {
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entry:
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%vt = alloca [2 x double], align 16
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br i1 undef, label %cleanup.4091, label %for.cond.3850
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unreachable:
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unreachable
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for.cond.3850:
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br i1 undef, label %land.rhs.3853, label %land.end.3857
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land.rhs.3853:
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br label %land.end.3857
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land.end.3857:
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%0 = phi i1 [ false, %for.cond.3850 ], [ false, %land.rhs.3853 ]
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br i1 %0, label %unreachable, label %unreachable
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cleanup.4091:
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ret void
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}
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attributes #0 = { ssp }
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attributes #1 = { noinline optnone ssp }
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