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353fbd3516
Using fwrite and fread was very *very* slow. The resulting code was multiple times slower than GCC's implementation of gcov. Replace the fwrite/fread system with an mmap() version. If the `.gcda' file doesn't exist, we (re)allocate a buffer that we write into. That gets written to the `.gcda' file in one chunk. If the `.gcda' file already exists, we simply mmap() the file, modify the mapped data, and use msync() to write the contents out to disk. It's much easier than implementing our own buffering scheme, and we don't have to use fwrite's and fread's buffering. For those who are numbers-oriented, here are some timings: GCC Verison ----------- `.gcda' files don't exist: 23s `.gcda' files do exist: 14s LLVM Version (before this change) --------------------------------- `.gcda' files don't exist: 28s `.gcda' files do exist: 28s LLVM Version (with this change) ------------------------------- `.gcda' files don't exist: 18s `.gcda' files do exist: 4s It's a win-win-win-win-lose-win-win scenario! <rdar://problem/13466086> llvm-svn: 182563
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
/* ===-- limits.h - stub SDK header for compiler-rt -------------------------===
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*
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* The LLVM Compiler Infrastructure
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*
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* This file is dual licensed under the MIT and the University of Illinois Open
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* Source Licenses. See LICENSE.TXT for details.
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*
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* ===-----------------------------------------------------------------------===
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*
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* This is a stub SDK header file. This file is not part of the interface of
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* this library nor an official version of the appropriate SDK header. It is
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* intended only to stub the features of this header required by compiler-rt.
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*
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* ===-----------------------------------------------------------------------===
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*/
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#ifndef __SYS_MMAN_H__
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#define __SYS_MMAN_H__
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typedef __SIZE_TYPE__ size_t;
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#define PROT_NONE 0x00
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#define PROT_READ 0x01
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#define PROT_WRITE 0x02
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#define PROT_EXEC 0x04
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#define MAP_SHARED 0x0001
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#define MAP_PRIVATE 0x0002
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#define MAP_FILE 0x0000
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#define MAP_ANON 0x1000
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#define MS_ASYNC 0x0001
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#define MS_INVALIDATE 0x0002
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#define MS_SYNC 0x0010
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extern void *mmap(void *addr, size_t len, int prot, int flags, int fd,
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long long offset)
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__attribute__((__nothrow__));
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extern int munmap(void *addr, size_t len)
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__attribute__((__nothrow__));
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extern int msync(void *addr, size_t len, int flags)
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__attribute__((__nothrow__));
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extern int mprotect (void *__addr, size_t __len, int __prot)
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__attribute__((__nothrow__));
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#endif /* __SYS_MMAN_H__ */
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