Performance improvement.

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>


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@182563 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 119 insertions, 3 deletions

diff --git a/SDKs/darwin/usr/include/fcntl.h b/SDKs/darwin/usr/include/fcntl.h
new file mode 100644
index 00000000..a5f91e3a
--- /dev/null
+++ b/SDKs/darwin/usr/include/fcntl.h
@@ -0,0 +1,17 @@
+/* ===-- fcntl.h - stub SDK header for compiler-rt --------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===-----------------------------------------------------------------------===
+ *
+ * This is a stub SDK header file. This file is not part of the interface of
+ * this library nor an official version of the appropriate SDK header. It is
+ * intended only to stub the features of this header required by compiler-rt.
+ *
+ * ===-----------------------------------------------------------------------===
+ */
+
+#include <sys/fcntl.h>
diff --git a/SDKs/darwin/usr/include/stdio.h b/SDKs/darwin/usr/include/stdio.h
index 5bbd8a55..006652fb 100644
--- a/SDKs/darwin/usr/include/stdio.h
+++ b/SDKs/darwin/usr/include/stdio.h
@@ -24,15 +24,18 @@ extern "C" {
 typedef struct __sFILE FILE;
 typedef __SIZE_TYPE__ size_t;
 
-/* Determine the appropriate fopen() and fwrite() functions. */
+/* Determine the appropriate fdopen, fopen(), and fwrite() functions. */
 #if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
 #  if defined(__i386)
+#    define __FDOPEN_NAME  "_fdopen$UNIX2003"
 #    define __FOPEN_NAME "_fopen$UNIX2003"
 #    define __FWRITE_NAME "_fwrite$UNIX2003"
 #  elif defined(__x86_64__)
+#    define __FDOPEN_NAME  "_fdopen"
 #    define __FOPEN_NAME "_fopen"
 #    define __FWRITE_NAME "_fwrite"
 #  elif defined(__arm)
+#    define __FDOPEN_NAME  "_fdopen"
 #    define __FOPEN_NAME "_fopen"
 #    define __FWRITE_NAME "_fwrite"
 #  else
@@ -40,9 +43,11 @@ typedef __SIZE_TYPE__ size_t;
 #  endif
 #elif defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
 #  if defined(__i386) || defined (__x86_64)
+#    define __FDOPEN_NAME  "_fdopen"
 #    define __FOPEN_NAME "_fopen"
 #    define __FWRITE_NAME "_fwrite"
 #  elif defined(__arm)
+#    define __FDOPEN_NAME  "_fdopen"
 #    define __FOPEN_NAME "_fopen"
 #    define __FWRITE_NAME "_fwrite"
 #  else
@@ -68,14 +73,13 @@ extern FILE *__stderrp;
 int fclose(FILE *);
 int fflush(FILE *);
 FILE *fopen(const char * __restrict, const char * __restrict) __asm(__FOPEN_NAME);
+FILE *fdopen(int, const char *) __asm(__FDOPEN_NAME);
 int fprintf(FILE * __restrict, const char * __restrict, ...);
 size_t fwrite(const void * __restrict, size_t, size_t, FILE * __restrict)
   __asm(__FWRITE_NAME);
 size_t fread(void * __restrict, size_t, size_t, FILE * __restrict);
 long ftell(FILE *);
 int fseek(FILE *, long, int);
-void setbuf(FILE * __restrict, char * __restrict);
-
 int snprintf(char * __restrict, size_t, const char * __restrict, ...);
 
 #if defined(__cplusplus)
diff --git a/SDKs/darwin/usr/include/stdlib.h b/SDKs/darwin/usr/include/stdlib.h
index 7c973dcc..b6d3171c 100644
--- a/SDKs/darwin/usr/include/stdlib.h
+++ b/SDKs/darwin/usr/include/stdlib.h
@@ -27,5 +27,6 @@ int atoi(const char *);
 void free(void *);
 char *getenv(const char *);
 void *malloc(size_t);
+void *realloc(void *, size_t);
 
 #endif /* __STDLIB_H__ */
diff --git a/SDKs/darwin/usr/include/sys/fcntl.h b/SDKs/darwin/usr/include/sys/fcntl.h
new file mode 100644
index 00000000..b71706bf
--- /dev/null
+++ b/SDKs/darwin/usr/include/sys/fcntl.h
@@ -0,0 +1,52 @@
+/* ===-- fcntl.h - stub SDK header for compiler-rt --------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===-----------------------------------------------------------------------===
+ *
+ * This is a stub SDK header file. This file is not part of the interface of
+ * this library nor an official version of the appropriate SDK header. It is
+ * intended only to stub the features of this header required by compiler-rt.
+ *
+ * ===-----------------------------------------------------------------------===
+ */
+
+#ifndef _SYS_FCNTL_H_
+#define _SYS_FCNTL_H_
+
+/* Determine the appropriate open function. */
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#  if defined(__i386)
+#    define __OPEN_NAME  "_open$UNIX2003"
+#  elif defined(__x86_64__)
+#    define __OPEN_NAME  "_open"
+#  elif defined(__arm)
+#    define __OPEN_NAME  "_open"
+#  else
+#    error "unrecognized architecture for targetting OS X"
+#  endif
+#elif defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
+#  if defined(__i386) || defined (__x86_64)
+#    define __OPEN_NAME  "_open"
+#  elif defined(__arm)
+#    define __OPEN_NAME  "_open"
+#  else
+#    error "unrecognized architecture for targetting iOS"
+#  endif
+#else
+#  error "unrecognized architecture for targetting Darwin"
+#endif
+
+#define O_RDONLY   0x0000    /* open for reading only */
+#define O_WRONLY   0x0001    /* open for writing only */
+#define O_RDWR     0x0002    /* open for reading and writing */
+#define O_ACCMODE  0x0003    /* mask for above modes */
+
+#define O_CREAT    0x0200    /* create if nonexistant */
+
+int open(const char *, int, ...) __asm(__OPEN_NAME);
+
+#endif /* !_SYS_FCNTL_H_ */
diff --git a/SDKs/darwin/usr/include/sys/mman.h b/SDKs/darwin/usr/include/sys/mman.h
new file mode 100644
index 00000000..84561f1b
--- /dev/null
+++ b/SDKs/darwin/usr/include/sys/mman.h
@@ -0,0 +1,42 @@
+/* ===-- mman.h - stub SDK header for compiler-rt ---------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===-----------------------------------------------------------------------===
+ *
+ * This is a stub SDK header file. This file is not part of the interface of
+ * this library nor an official version of the appropriate SDK header. It is
+ * intended only to stub the features of this header required by compiler-rt.
+ *
+ * ===-----------------------------------------------------------------------===
+ */
+
+#ifndef __SYS_MMAN_H__
+#define __SYS_MMAN_H__
+
+typedef __SIZE_TYPE__ size_t;
+
+#define PROT_NONE     0x00
+#define PROT_READ     0x01
+#define PROT_WRITE    0x02
+#define PROT_EXEC     0x04
+
+#define MAP_SHARED    0x0001
+#define MAP_PRIVATE   0x0002
+
+#define MAP_FILE      0x0000
+#define MAP_ANON      0x1000
+
+#define MS_ASYNC      0x0001
+#define MS_INVALIDATE 0x0002
+#define MS_SYNC       0x0010
+
+void *mmap(void *addr, size_t len, int prot, int flags, int fd,
+           long long offset);
+int munmap(void *addr, size_t len);
+int msync(void *addr, size_t len, int flags);
+
+#endif /* __SYS_MMAN_H__ */