461a1836d3
1) Use a static array of pointer to retain the dummy vars. 2) Associate liveness of the array with that of the runtime hook variable __llvm_profile_runtime. 3) Perform the runtime initialization through the runtime hook variable. 4) Preserve the runtime hook variable using the -u linker flag. Reviewed By: hubert.reinterpretcast Differential Revision: https://reviews.llvm.org/D136192
33 lines
1.1 KiB
C++
33 lines
1.1 KiB
C++
//===- InstrProfilingRuntime.cpp - PGO runtime initialization -------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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extern "C" {
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#include "InstrProfiling.h"
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static int RegisterRuntime() {
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__llvm_profile_initialize();
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return 0;
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}
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#ifndef _AIX
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/* int __llvm_profile_runtime */
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COMPILER_RT_VISIBILITY int INSTR_PROF_PROFILE_RUNTIME_VAR;
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static int Registration = RegisterRuntime();
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#else
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extern COMPILER_RT_VISIBILITY void *__llvm_profile_keep[];
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/* On AIX, when linking with -bcdtors:csect, the variable whose constructor does
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* the registration needs to be explicitly kept, hence we reuse the runtime hook
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* variable to do the registration since it'll be kept via the -u linker flag.
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* Create a volatile reference to __llvm_profile_keep to keep the array alive.*/
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COMPILER_RT_VISIBILITY int INSTR_PROF_PROFILE_RUNTIME_VAR =
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((void)*(void *volatile *)__llvm_profile_keep, RegisterRuntime());
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#endif
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}
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