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
44 lines
1.5 KiB
C
44 lines
1.5 KiB
C
/* ===-- stdio.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 __STDIO_H__
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#define __STDIO_H__
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typedef __SIZE_TYPE__ size_t;
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struct _IO_FILE;
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typedef struct _IO_FILE FILE;
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extern struct _IO_FILE *stdin;
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extern struct _IO_FILE *stdout;
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extern struct _IO_FILE *stderr;
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#define SEEK_SET 0 /* set file offset to offset */
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#define SEEK_CUR 1 /* set file offset to current plus offset */
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#define SEEK_END 2 /* set file offset to EOF plus offset */
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extern int fclose(FILE *);
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extern int fflush(FILE *);
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extern FILE *fopen(const char * restrict, const char * restrict);
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extern FILE *fdopen(int, const char * restrict);
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extern int fprintf(FILE * restrict, const char * restrict, ...);
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extern size_t fwrite(const void * restrict, size_t, size_t, FILE * restrict);
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extern size_t fread(void * restrict, size_t, size_t, FILE * restrict);
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extern long ftell(FILE *);
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extern int fseek(FILE *, long, int);
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#endif /* __STDIO_H__ */
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