b8cc3ba409
As before we only skip instrumenting probe of `unwind`(`KnownColdBlock`) block, this PR extends to skip the both EH flow from `invoke`, i.e. also skip the `normal` dest. For more contexts: when doing call-to-invoke conversion, the block is split by the `invoke` and two extra blocks(`normal` and `unwind`) are added. With this PR, the instrumentation is the same as the one before the call-to-invoke conversion. One significant benefit is this can help mitigate the "unstable IR" issue(https://discourse.llvm.org/t/ipo-for-linkonce-odr-functions/69404), the two versions now are on the same probe instrumentation, expected to be the same checksum. To achieve the same checksum, some tweaks is needed: - Now it also skips incrementing the probe ID for the skipped probe. - The checksum is also computed based on the CFG that skips the EH edges. We observed this fixes ~5% mismatched samples.
44 lines
1.2 KiB
LLVM
44 lines
1.2 KiB
LLVM
; REQUIRES: x86_64-linux
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; RUN: opt < %s -passes=pseudo-probe -function-sections -S -o - | FileCheck %s
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;; Check the generation of pseudoprobe intrinsic call for non-EH blocks only.
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declare i32 @__gxx_personality_v0(...)
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declare i32 @llvm.eh.typeid.for(ptr) nounwind
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declare ptr @__cxa_begin_catch(ptr)
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declare void @__cxa_end_catch()
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declare void @bar()
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@_ZTIi = external constant ptr
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define void @foo() uwtable ssp personality ptr @__gxx_personality_v0 {
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entry:
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; CHECK: call void @llvm.pseudoprobe
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invoke void @bar()
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to label %ret unwind label %lpad
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ret:
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; CHECK-NOT: call void @llvm.pseudoprobe
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ret void
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lpad: ; preds = %entry
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; CHECK-NOT: call void @llvm.pseudoprobe
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%exn = landingpad {ptr, i32}
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catch ptr @_ZTIi
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%eh.exc = extractvalue { ptr, i32 } %exn, 0
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%eh.selector = extractvalue { ptr, i32 } %exn, 1
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%0 = call i32 @llvm.eh.typeid.for(ptr @_ZTIi) nounwind
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%1 = icmp eq i32 %eh.selector, %0
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br i1 %1, label %catch, label %eh.resume
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catch:
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; CHECK-NOT: call void @llvm.pseudoprobe
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%ignored = call ptr @__cxa_begin_catch(ptr %eh.exc) nounwind
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call void @__cxa_end_catch() nounwind
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br label %ret
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eh.resume:
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; CHECK-NOT: call void @llvm.pseudoprobe
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resume { ptr, i32 } %exn
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}
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