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llvm-project/llvm/test/Instrumentation/InstrProfiling/no-counters.ll

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[InstrProfiling] Emit the runtime hook when no counters are lowered The API verification tool tapi has difficulty processing frameworks which enable code coverage, but which have no code. The profile lowering pass does not emit the runtime hook in this case because no counters are lowered. While the hook is not needed for program correctness (the profile runtime doesn't have to be linked in), it's needed to allow tapi to validate the exported symbol set of instrumented binaries. It was not possible to add a workaround in tapi for empty binaries due to an architectural issue: tapi generates its expected symbol set before it inspects a binary. Changing that model has a higher cost than simply forcing llvm to always emit the runtime hook. rdar://36076904 Differential Revision: https://reviews.llvm.org/D43794 llvm-svn: 326350
2018-03-01 03:00:08 +08:00
;; Emit the runtime hook even if there are no counter increments.
InstrProf: An intrinsic and lowering for instrumentation based profiling Introduce the ``llvm.instrprof_increment`` intrinsic and the ``-instrprof`` pass. These provide the infrastructure for writing counters for profiling, as in clang's ``-fprofile-instr-generate``. The implementation of the instrprof pass is ported directly out of the CodeGenPGO classes in clang, and with the followup in clang that rips that code out to use these new intrinsics this ends up being NFC. Doing the instrumentation this way opens some doors in terms of improving the counter performance. For example, this will make it simple to experiment with alternate lowering strategies, and allows us to try handling profiling specially in some optimizations if we want to. Finally, this drastically simplifies the frontend and puts all of the lowering logic in one place. llvm-svn: 223672
2014-12-09 02:02:35 +08:00
[InstrProfiling] Emit the runtime hook when no counters are lowered The API verification tool tapi has difficulty processing frameworks which enable code coverage, but which have no code. The profile lowering pass does not emit the runtime hook in this case because no counters are lowered. While the hook is not needed for program correctness (the profile runtime doesn't have to be linked in), it's needed to allow tapi to validate the exported symbol set of instrumented binaries. It was not possible to add a workaround in tapi for empty binaries due to an architectural issue: tapi generates its expected symbol set before it inspects a binary. Changing that model has a higher cost than simply forcing llvm to always emit the runtime hook. rdar://36076904 Differential Revision: https://reviews.llvm.org/D43794 llvm-svn: 326350
2018-03-01 03:00:08 +08:00
; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -instrprof -S | FileCheck %s -check-prefixes=ALL,DARWIN
; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,DARWIN
; RUN: opt < %s -mtriple=x86_64-linux-unknown -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,LINUX
; ALL-NOT: @__profc
; ALL-NOT: @__profd
; DARWIN: @__llvm_profile_runtime
; LINUX-NOT: @__llvm_profile_runtime
InstrProf: An intrinsic and lowering for instrumentation based profiling Introduce the ``llvm.instrprof_increment`` intrinsic and the ``-instrprof`` pass. These provide the infrastructure for writing counters for profiling, as in clang's ``-fprofile-instr-generate``. The implementation of the instrprof pass is ported directly out of the CodeGenPGO classes in clang, and with the followup in clang that rips that code out to use these new intrinsics this ends up being NFC. Doing the instrumentation this way opens some doors in terms of improving the counter performance. For example, this will make it simple to experiment with alternate lowering strategies, and allows us to try handling profiling specially in some optimizations if we want to. Finally, this drastically simplifies the frontend and puts all of the lowering logic in one place. llvm-svn: 223672
2014-12-09 02:02:35 +08:00
define void @foo() {
ret void
}