[llvm] r250199 - [PGO]: Eliminate calls to __llvm_profile_register_function for Linux.

[Justin Bogner via llvm-commits]

Xinliang David Li via llvm-commits <llvm-commits at lists.llvm.org> writes:
> Author: davidxl
> Date: Tue Oct 13 13:39:48 2015
> New Revision: 250199
>
> URL: http://llvm.org/viewvc/llvm-project?rev=250199&view=rev
> Log:
>
> [PGO]: Eliminate calls to __llvm_profile_register_function for Linux.
>
> On Linux, the profile runtime can use __start_SECTNAME and __stop_SECTNAME
> symbols defined by the linker to locate the start and end location of
> a named section (with C name). This eliminates the need for instrumented
> binary to call __llvm_profile_register_function during start-up time.
>
> Modified:
>     llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp
>     llvm/trunk/test/Instrumentation/InstrProfiling/platform.ll
>
> Modified: llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp?rev=250199&r1=250198&r2=250199&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp (original)
> +++ llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp Tue Oct 13 13:39:48 2015
> @@ -257,6 +257,9 @@ void InstrProfiling::emitRegistration()
>    if (Triple(M->getTargetTriple()).isOSDarwin())
>      return;
>  
> +  // Use linker script magic to get data/cnts/name start/end.
> +  if (Triple(M->getTargetTriple()).isOSLinux()) return;
> +
>    // Construct the function.
>    auto *VoidTy = Type::getVoidTy(M->getContext());
>    auto *VoidPtrTy = Type::getInt8PtrTy(M->getContext());
>
> Modified: llvm/trunk/test/Instrumentation/InstrProfiling/platform.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/InstrProfiling/platform.ll?rev=250199&r1=250198&r2=250199&view=diff
> ==============================================================================
> --- llvm/trunk/test/Instrumentation/InstrProfiling/platform.ll (original)
> +++ llvm/trunk/test/Instrumentation/InstrProfiling/platform.ll Tue Oct 13 13:39:48 2015
> @@ -1,7 +1,8 @@
>  ;; Checks for platform specific section names and initialization code.
>  
>  ; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -instrprof -S | FileCheck %s -check-prefix=MACHO
> -; RUN: opt < %s -mtriple=x86_64-unknown-linux -instrprof -S | FileCheck %s -check-prefix=ELF
> +; RUN: opt < %s -mtriple=x86_64-unknown-linux -instrprof -S | FileCheck %s -check-prefix=LINUX
> +; RUN: opt < %s -mtriple=x86_64-unknown-freebsd -instrprof -S | FileCheck %s -check-prefix=BSD
>  
>  @__llvm_profile_name_foo = hidden constant [3 x i8] c"foo"
>  ; MACHO: @__llvm_profile_name_foo = hidden constant [3 x i8] c"foo", section "__DATA,__llvm_prf_names", align 1
> @@ -11,7 +12,8 @@
>  ; ELF: @__llvm_profile_counters_foo = hidden global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", align 8
>  
>  ; MACHO: @__llvm_profile_data_foo = hidden constant {{.*}}, section "__DATA,__llvm_prf_data", align 8
> -; ELF: @__llvm_profile_data_foo = hidden constant {{.*}}, section "__llvm_prf_data", align 8
> +; LINUX: @__llvm_profile_data_foo = hidden constant {{.*}}, section "__llvm_prf_data", align 8
> +; BSD: @__llvm_profile_data_foo = hidden constant {{.*}}, section "__llvm_prf_data", align 8
>  define void @foo() {
>    call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__llvm_profile_name_foo, i32 0, i32 0), i64 0, i32 1, i32 0)
>    ret void
> @@ -23,7 +25,8 @@ declare void @llvm.instrprof.increment(i
>  ;; symbols by their sections.
>  
>  ; MACHO-NOT: define internal void @__llvm_profile_register_functions
> -; ELF: define internal void @__llvm_profile_register_functions
> +; LINUX-NOT: define internal void @__llvm_profile_register_functions
> +; BSD: define internal void @__llvm_profile_register_functions
>  
>  ; MACHO-NOT: define internal void @__llvm_profile_init
> -; ELF: define internal void @__llvm_profile_init
> +; BSD: define internal void @__llvm_profile_init

LINUX-NOT?

>
>
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