ae0cafece8
subtarget features for indirect calls and indirect branches. This is in preparation for enabling *only* the call retpolines when using speculative load hardening. I've continued to use subtarget features for now as they continue to seem the best fit given the lack of other retpoline like constructs so far. The LLVM side is pretty simple. I'd like to eventually get rid of the old feature, but not sure what backwards compatibility issues that will cause. This does remove the "implies" from requesting an external thunk. This always seemed somewhat questionable and is now clearly not desirable -- you specify a thunk the same way no matter which set of things are getting retpolines. I really want to keep this nicely isolated from end users and just an LLVM implementation detail, so I've moved the `-mretpoline` flag in Clang to no longer rely on a specific subtarget feature by that name and instead to be directly handled. In some ways this is simpler, but in order to preserve existing behavior I've had to add some fallback code so that users who relied on merely passing -mretpoline-external-thunk continue to get the same behavior. We should eventually remove this I suspect (we have never tested that it works!) but I've not done that in this patch. Differential Revision: https://reviews.llvm.org/D51150 llvm-svn: 340515
167 lines
5.3 KiB
LLVM
167 lines
5.3 KiB
LLVM
; RUN: llc -mtriple=x86_64-unknown < %s | FileCheck %s --implicit-check-not="jmp.*\*" --implicit-check-not="call.*\*" --check-prefix=X64
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; RUN: llc -mtriple=x86_64-unknown -O0 < %s | FileCheck %s --implicit-check-not="jmp.*\*" --implicit-check-not="call.*\*" --check-prefix=X64FAST
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; RUN: llc -mtriple=i686-unknown < %s | FileCheck %s --implicit-check-not="jmp.*\*" --implicit-check-not="call.*\*" --check-prefix=X86
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; RUN: llc -mtriple=i686-unknown -O0 < %s | FileCheck %s --implicit-check-not="jmp.*\*" --implicit-check-not="call.*\*" --check-prefix=X86FAST
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declare void @bar(i32)
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; Test a simple indirect call and tail call.
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define void @icall_reg(void (i32)* %fp, i32 %x) #0 {
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entry:
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tail call void @bar(i32 %x)
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tail call void %fp(i32 %x)
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tail call void @bar(i32 %x)
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tail call void %fp(i32 %x)
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ret void
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}
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; X64-LABEL: icall_reg:
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; X64-DAG: movq %rdi, %[[fp:[^ ]*]]
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; X64-DAG: movl %esi, %[[x:[^ ]*]]
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; X64: movl %esi, %edi
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; X64: callq bar
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; X64-DAG: movl %[[x]], %edi
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; X64-DAG: movq %[[fp]], %r11
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; X64: callq __x86_indirect_thunk_r11
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; X64: movl %[[x]], %edi
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; X64: callq bar
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; X64-DAG: movl %[[x]], %edi
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; X64-DAG: movq %[[fp]], %r11
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; X64: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X64FAST-LABEL: icall_reg:
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; X64FAST: callq bar
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; X64FAST: callq __x86_indirect_thunk_r11
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; X64FAST: callq bar
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; X64FAST: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X86-LABEL: icall_reg:
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; X86-DAG: movl 12(%esp), %[[fp:[^ ]*]]
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; X86-DAG: movl 16(%esp), %[[x:[^ ]*]]
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; X86: pushl %[[x]]
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; X86: calll bar
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; X86: movl %[[fp]], %eax
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; X86: pushl %[[x]]
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; X86: calll __x86_indirect_thunk_eax
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; X86: pushl %[[x]]
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; X86: calll bar
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; X86: movl %[[fp]], %eax
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; X86: pushl %[[x]]
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; X86: calll __x86_indirect_thunk_eax
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; X86-NOT: # TAILCALL
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; X86FAST-LABEL: icall_reg:
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; X86FAST: calll bar
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; X86FAST: calll __x86_indirect_thunk_eax
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; X86FAST: calll bar
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; X86FAST: calll __x86_indirect_thunk_eax
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@global_fp = external global void (i32)*
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; Test an indirect call through a global variable.
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define void @icall_global_fp(i32 %x, void (i32)** %fpp) #0 {
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%fp1 = load void (i32)*, void (i32)** @global_fp
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call void %fp1(i32 %x)
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%fp2 = load void (i32)*, void (i32)** @global_fp
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tail call void %fp2(i32 %x)
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ret void
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}
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; X64-LABEL: icall_global_fp:
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; X64-DAG: movl %edi, %[[x:[^ ]*]]
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; X64-DAG: movq global_fp(%rip), %r11
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; X64: callq __x86_indirect_thunk_r11
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; X64-DAG: movl %[[x]], %edi
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; X64-DAG: movq global_fp(%rip), %r11
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; X64: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X64FAST-LABEL: icall_global_fp:
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; X64FAST: movq global_fp(%rip), %r11
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; X64FAST: callq __x86_indirect_thunk_r11
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; X64FAST: movq global_fp(%rip), %r11
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; X64FAST: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X86-LABEL: icall_global_fp:
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; X86: movl global_fp, %eax
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; X86: pushl 4(%esp)
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; X86: calll __x86_indirect_thunk_eax
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; X86: addl $4, %esp
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; X86: movl global_fp, %eax
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; X86: jmp __x86_indirect_thunk_eax # TAILCALL
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; X86FAST-LABEL: icall_global_fp:
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; X86FAST: calll __x86_indirect_thunk_eax
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; X86FAST: jmp __x86_indirect_thunk_eax # TAILCALL
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%struct.Foo = type { void (%struct.Foo*)** }
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; Test an indirect call through a vtable.
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define void @vcall(%struct.Foo* %obj) #0 {
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%vptr_field = getelementptr %struct.Foo, %struct.Foo* %obj, i32 0, i32 0
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%vptr = load void (%struct.Foo*)**, void (%struct.Foo*)*** %vptr_field
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%vslot = getelementptr void(%struct.Foo*)*, void(%struct.Foo*)** %vptr, i32 1
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%fp = load void(%struct.Foo*)*, void(%struct.Foo*)** %vslot
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tail call void %fp(%struct.Foo* %obj)
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tail call void %fp(%struct.Foo* %obj)
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ret void
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}
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; X64-LABEL: vcall:
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; X64: movq %rdi, %[[obj:[^ ]*]]
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; X64: movq (%rdi), %[[vptr:[^ ]*]]
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; X64: movq 8(%[[vptr]]), %[[fp:[^ ]*]]
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; X64: movq %[[fp]], %r11
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; X64: callq __x86_indirect_thunk_r11
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; X64-DAG: movq %[[obj]], %rdi
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; X64-DAG: movq %[[fp]], %r11
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; X64: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X64FAST-LABEL: vcall:
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; X64FAST: callq __x86_indirect_thunk_r11
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; X64FAST: jmp __x86_indirect_thunk_r11 # TAILCALL
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; X86-LABEL: vcall:
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; X86: movl 8(%esp), %[[obj:[^ ]*]]
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; X86: movl (%[[obj]]), %[[vptr:[^ ]*]]
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; X86: movl 4(%[[vptr]]), %[[fp:[^ ]*]]
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; X86: movl %[[fp]], %eax
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; X86: pushl %[[obj]]
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; X86: calll __x86_indirect_thunk_eax
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; X86: addl $4, %esp
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; X86: movl %[[fp]], %eax
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; X86: jmp __x86_indirect_thunk_eax # TAILCALL
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; X86FAST-LABEL: vcall:
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; X86FAST: calll __x86_indirect_thunk_eax
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; X86FAST: jmp __x86_indirect_thunk_eax # TAILCALL
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declare void @direct_callee()
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define void @direct_tail() #0 {
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tail call void @direct_callee()
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ret void
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}
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; X64-LABEL: direct_tail:
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; X64: jmp direct_callee # TAILCALL
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; X64FAST-LABEL: direct_tail:
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; X64FAST: jmp direct_callee # TAILCALL
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; X86-LABEL: direct_tail:
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; X86: jmp direct_callee # TAILCALL
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; X86FAST-LABEL: direct_tail:
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; X86FAST: jmp direct_callee # TAILCALL
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; Lastly check that no thunks were emitted.
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; X64-NOT: __{{.*}}_retpoline_{{.*}}:
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; X64FAST-NOT: __{{.*}}_retpoline_{{.*}}:
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; X86-NOT: __{{.*}}_retpoline_{{.*}}:
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; X86FAST-NOT: __{{.*}}_retpoline_{{.*}}:
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attributes #0 = { "target-features"="+retpoline-indirect-calls,+retpoline-external-thunk" }
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