diff --git a/clang/docs/SourceBasedCodeCoverage.rst b/clang/docs/SourceBasedCodeCoverage.rst
--- a/clang/docs/SourceBasedCodeCoverage.rst
+++ b/clang/docs/SourceBasedCodeCoverage.rst
@@ -90,12 +90,11 @@
* "%c" expands out to nothing, but enables a mode in which profile counter
updates are continuously synced to a file. This means that if the
instrumented program crashes, or is killed by a signal, perfect coverage
- information can still be recovered. Continuous mode is not yet compatible with
- the "%Nm" merging mode described above, does not support value profiling for
- PGO, and is only supported on Darwin. Support for Linux may be mostly
- complete but requires testing, and support for Fuchsia/Windows may require
- more extensive changes: please get involved if you are interested in porting
- this feature.
+ information can still be recovered. Continuous mode does not support value
+ profiling for PGO, and is only supported on Darwin at the moment. Support for
+ Linux may be mostly complete but requires testing, and support for
+ Fuchsia/Windows may require more extensive changes: please get involved if
+ you are interested in porting this feature.
.. code-block:: console
diff --git a/compiler-rt/lib/profile/InstrProfilingBuffer.c b/compiler-rt/lib/profile/InstrProfilingBuffer.c
--- a/compiler-rt/lib/profile/InstrProfilingBuffer.c
+++ b/compiler-rt/lib/profile/InstrProfilingBuffer.c
@@ -10,11 +10,7 @@
#include "InstrProfilingInternal.h"
#include "InstrProfilingPort.h"
-/* When continuous mode is enabled (%c), this parameter is set to 1. This is
- * incompatible with the in-process merging mode. Lifting this restriction
- * may be complicated, as merging mode requires a lock on the profile, and
- * mmap() mode would require that lock to be held for the entire process
- * lifetime.
+/* When continuous mode is enabled (%c), this parameter is set to 1.
*
* This parameter is defined here in InstrProfilingBuffer.o, instead of in
* InstrProfilingFile.o, to sequester all libc-dependent code in
diff --git a/compiler-rt/lib/profile/InstrProfilingFile.c b/compiler-rt/lib/profile/InstrProfilingFile.c
--- a/compiler-rt/lib/profile/InstrProfilingFile.c
+++ b/compiler-rt/lib/profile/InstrProfilingFile.c
@@ -380,11 +380,6 @@
if (!Filename)
return;
- /* By pass file truncation to allow online raw profile
- * merging. */
- if (lprofCurFilename.MergePoolSize)
- return;
-
/* Only create the profile directory and truncate an existing profile once.
* In continuous mode, this is necessary, as the profile is written-to by the
* runtime initializer. */
@@ -397,8 +392,14 @@
setenv(LPROF_INIT_ONCE_ENV, LPROF_INIT_ONCE_ENV, 1);
#endif
+ /* Create the profile dir (even if online merging is enabled), so that
+ * the profile file can be set up if continuous mode is enabled. */
createProfileDir(Filename);
+ /* By pass file truncation to allow online raw profile merging. */
+ if (lprofCurFilename.MergePoolSize)
+ return;
+
/* Truncate the file. Later we'll reopen and append. */
File = fopen(Filename, "w");
if (!File)
@@ -406,6 +407,33 @@
fclose(File);
}
+#ifndef _MSC_VER
+static void assertIsZero(int *i) {
+ if (*i)
+ PROF_WARN("Expected flag to be 0, but got: %d\n", *i);
+}
+#endif
+
+/* Write a partial profile to \p Filename, which is required to be backed by
+ * the open file object \p File. */
+static int writeProfileWithFileObject(const char *Filename, FILE *File) {
+ setProfileFile(File);
+ int rc = writeFile(Filename);
+ if (rc)
+ PROF_ERR("Failed to write file \"%s\": %s\n", Filename, strerror(errno));
+ setProfileFile(NULL);
+ return rc;
+}
+
+/* Unlock the profile \p File and clear the unlock flag. */
+static void unlockProfile(int *ProfileRequiresUnlock, FILE *File) {
+ if (!*ProfileRequiresUnlock) {
+ PROF_WARN("%s", "Expected to require profile unlock\n");
+ }
+ lprofUnlockFileHandle(File);
+ *ProfileRequiresUnlock = 0;
+}
+
static void initializeProfileForContinuousMode(void) {
#if defined(__Fuchsia__) || defined(_WIN32)
PROF_ERR("%s\n", "Continuous mode not yet supported on Fuchsia or Windows.");
@@ -438,28 +466,72 @@
return;
}
- /* Open the raw profile in append mode. */
int Length = getCurFilenameLength();
char *FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
const char *Filename = getCurFilename(FilenameBuf, 0);
if (!Filename)
return;
- FILE *File = fopen(Filename, "a+b");
- if (!File)
- return;
- int Fileno = fileno(File);
+ FILE *File = NULL;
+ off_t CurrentFileOffset = 0;
+ off_t OffsetModPage = 0;
+
+ /* Whether an exclusive lock on the profile must be dropped after init.
+ * Use a cleanup to warn if the unlock does not occur. */
+ COMPILER_RT_CLEANUP(assertIsZero) int ProfileRequiresUnlock = 0;
+
+ if (!doMerging()) {
+ /* We are not merging profiles, so open the raw profile in append mode. */
+ File = fopen(Filename, "a+b");
+ if (!File)
+ return;
+
+ /* Check that the offset within the file is page-aligned. */
+ CurrentFileOffset = ftello(File);
+ OffsetModPage = CurrentFileOffset % PageSize;
+ if (OffsetModPage != 0) {
+ PROF_ERR("Continuous counter sync mode is enabled, but raw profile is not"
+ "page-aligned. CurrentFileOffset = %" PRIu64 ", pagesz = %u.\n",
+ (uint64_t)CurrentFileOffset, PageSize);
+ return;
+ }
- /* Check that the offset within the file is page-aligned. */
- off_t CurrentFileOffset = ftello(File);
- off_t OffsetModPage = CurrentFileOffset % PageSize;
- if (OffsetModPage != 0) {
- PROF_ERR("Continuous counter sync mode is enabled, but raw profile is not"
- "page-aligned. CurrentFileOffset = %" PRIu64 ", pagesz = %u.\n",
- (uint64_t) CurrentFileOffset, PageSize);
- return;
+ /* Grow the profile so that mmap() can succeed. Leak the file handle, as
+ * the file should stay open. */
+ if (writeProfileWithFileObject(Filename, File) != 0)
+ return;
+ } else {
+ /* We are merging profiles. Map the counter section as shared memory into
+ * the profile, i.e. into each participating process. An increment in one
+ * process should be visible to every other process with the same counter
+ * section mapped. */
+ File = lprofOpenFileEx(Filename);
+ if (!File)
+ return;
+
+ ProfileRequiresUnlock = 1;
+
+ uint64_t ProfileFileSize;
+ if (getProfileFileSizeForMerging(File, &ProfileFileSize) == -1)
+ return unlockProfile(&ProfileRequiresUnlock, File);
+
+ if (ProfileFileSize == 0) {
+ /* Grow the profile so that mmap() can succeed. Leak the file handle, as
+ * the file should stay open. */
+ if (writeProfileWithFileObject(Filename, File) != 0)
+ return unlockProfile(&ProfileRequiresUnlock, File);
+ } else {
+ /* The merged profile has a non-zero length. Check that it is compatible
+ * with the data in this process. */
+ char *ProfileBuffer;
+ if (mmapProfileForMerging(File, ProfileFileSize, &ProfileBuffer) == -1 ||
+ munmap(ProfileBuffer, ProfileFileSize) == -1)
+ return unlockProfile(&ProfileRequiresUnlock, File);
+ }
}
+ int Fileno = fileno(File);
+
/* Determine how much padding is needed before/after the counters and after
* the names. */
uint64_t PaddingBytesBeforeCounters, PaddingBytesAfterCounters,
@@ -474,14 +546,6 @@
CurrentFileOffset + sizeof(__llvm_profile_header) +
(DataSize * sizeof(__llvm_profile_data)) + PaddingBytesBeforeCounters;
- /* Write the partial profile. This grows the file to a point where the mmap()
- * can succeed. Leak the file handle, as the file should stay open. */
- setProfileFile(File);
- int rc = writeFile(Filename);
- if (rc)
- PROF_ERR("Failed to write file \"%s\": %s\n", Filename, strerror(errno));
- setProfileFile(NULL);
-
uint64_t *CounterMmap = (uint64_t *)mmap(
(void *)CountersBegin, PageAlignedCountersLength, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_SHARED, Fileno, FileOffsetToCounters);
@@ -494,8 +558,9 @@
" - FileOffsetToCounters: %" PRIu64 "\n",
strerror(errno), CountersBegin, PageAlignedCountersLength, Fileno,
FileOffsetToCounters);
- return;
}
+
+ unlockProfile(&ProfileRequiresUnlock, File);
#endif // defined(__Fuchsia__) || defined(_WIN32)
}
@@ -568,12 +633,6 @@
FilenamePat);
return -1;
}
- if (MergingEnabled) {
- PROF_WARN("%%c specifier can not be used with profile merging (%%m) "
- "in %s.\n",
- FilenamePat);
- return -1;
- }
__llvm_profile_enable_continuous_mode();
I++; /* advance to 'c' */
@@ -583,12 +642,6 @@
FilenamePat);
return -1;
}
- if (__llvm_profile_is_continuous_mode_enabled()) {
- PROF_WARN("%%c specifier can not be used with profile merging (%%m) "
- "in %s.\n",
- FilenamePat);
- return -1;
- }
MergingEnabled = 1;
if (FilenamePat[I] == 'm')
lprofCurFilename.MergePoolSize = 1;
diff --git a/compiler-rt/lib/profile/InstrProfilingPort.h b/compiler-rt/lib/profile/InstrProfilingPort.h
--- a/compiler-rt/lib/profile/InstrProfilingPort.h
+++ b/compiler-rt/lib/profile/InstrProfilingPort.h
@@ -22,6 +22,7 @@
/* Need to include <stdio.h> and <io.h> */
#define COMPILER_RT_FTRUNCATE(f,l) _chsize(_fileno(f),l)
#define COMPILER_RT_ALWAYS_INLINE __forceinline
+#define COMPILER_RT_CLEANUP(x)
#elif __GNUC__
#define COMPILER_RT_ALIGNAS(x) __attribute__((aligned(x)))
#define COMPILER_RT_VISIBILITY __attribute__((visibility("hidden")))
@@ -29,6 +30,7 @@
#define COMPILER_RT_ALLOCA __builtin_alloca
#define COMPILER_RT_FTRUNCATE(f,l) ftruncate(fileno(f),l)
#define COMPILER_RT_ALWAYS_INLINE inline __attribute((always_inline))
+#define COMPILER_RT_CLEANUP(x) __attribute__((cleanup(x)))
#endif
#if defined(__APPLE__)
diff --git a/compiler-rt/test/profile/ContinuousSyncMode/online-merging.c b/compiler-rt/test/profile/ContinuousSyncMode/online-merging.c
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/profile/ContinuousSyncMode/online-merging.c
@@ -0,0 +1,138 @@
+// Test the online merging mode (%m) along with continuous mode (%c).
+//
+// Create & cd into a temporary directory.
+// RUN: rm -rf %t.dir && mkdir -p %t.dir && cd %t.dir
+//
+// Create two DSOs and a driver program that uses them.
+// RUN: echo "void dso1(void) {}" > dso1.c
+// RUN: echo "void dso2(void) {}" > dso2.c
+// RUN: %clang_pgogen -dynamiclib -o %t.dir/dso1.dylib dso1.c
+// RUN: %clang_pgogen -dynamiclib -o %t.dir/dso2.dylib dso2.c
+// RUN: %clang_pgogen -o main.exe %s %t.dir/dso1.dylib %t.dir/dso2.dylib
+//
+// === Round 1 ===
+// Test merging+continuous mode without any file contention.
+//
+// RUN: env LLVM_PROFILE_FILE="%t.dir/profdir/%m%c.profraw" %run %t.dir/main.exe nospawn
+// RUN: llvm-profdata merge -o %t.profdata %t.dir/profdir
+// RUN: llvm-profdata show --counts --all-functions %t.profdata | FileCheck %s -check-prefix=ROUND1
+
+// ROUND1-LABEL: Counters:
+// ROUND1-DAG: dso1:
+// ROUND1-DAG: Hash: 0x{{.*}}
+// ROUND1-DAG: Counters: 1
+// ROUND1-DAG: Block counts: [1]
+// ROUND1-DAG: dso2:
+// ROUND1-DAG: Hash: 0x{{.*}}
+// ROUND1-DAG: Counters: 1
+// ROUND1-DAG: Block counts: [1]
+// ROUND1-DAG: main:
+// ROUND1-DAG: Hash: 0x{{.*}}
+// ROUND1-LABEL: Instrumentation level: IR
+// ROUND1-NEXT: Functions shown: 3
+// ROUND1-NEXT: Total functions: 3
+// ROUND1-NEXT: Maximum function count: 1
+// ROUND1-NEXT: Maximum internal block count: 1
+//
+// === Round 2 ===
+// Test merging+continuous mode with some file contention.
+//
+// RUN: env LLVM_PROFILE_FILE="%t.dir/profdir/%m%c.profraw" %run %t.dir/main.exe spawn 'LLVM_PROFILE_FILE=%t.dir/profdir/%m%c.profraw'
+// RUN: llvm-profdata merge -o %t.profdata %t.dir/profdir
+// RUN: llvm-profdata show --counts --all-functions %t.profdata | FileCheck %s -check-prefix=ROUND2
+
+// ROUND2-LABEL: Counters:
+// ROUND2-DAG: dso1:
+// ROUND2-DAG: Hash: 0x{{.*}}
+// ROUND2-DAG: Counters: 1
+// ROUND2-DAG: Block counts: [97]
+// ROUND2-DAG: dso2:
+// ROUND2-DAG: Hash: 0x{{.*}}
+// ROUND2-DAG: Counters: 1
+// ROUND2-DAG: Block counts: [97]
+// ROUND2-DAG: main:
+// ROUND2-DAG: Hash: 0x{{.*}}
+// ROUND2-LABEL: Instrumentation level: IR
+// ROUND2-NEXT: Functions shown: 3
+// ROUND2-NEXT: Total functions: 3
+// ROUND2-NEXT: Maximum function count: 97
+// ROUND2-NEXT: Maximum internal block count: 33
+
+#include <spawn.h>
+#include <sys/wait.h>
+#include <sys/errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+
+const int num_child_procs_to_spawn = 32;
+
+extern int __llvm_profile_is_continuous_mode_enabled(void);
+extern char *__llvm_profile_get_filename(void);
+
+void dso1(void);
+void dso2(void);
+
+// Change to "#define" for debug output.
+#undef DEBUG_TEST
+
+#ifdef DEBUG_TEST
+#define DEBUG(...) fprintf(stderr, __VA_ARGS__);
+#else
+#define DEBUG(...)
+#endif
+
+int main(int argc, char *const argv[]) {
+ if (strcmp(argv[1], "nospawn") == 0) {
+ DEBUG("Hello from child (pid = %d, cont-mode-enabled = %d, profile = %s).\n",
+ getpid(), __llvm_profile_is_continuous_mode_enabled(), __llvm_profile_get_filename());
+
+ dso1();
+ dso2();
+ return 0;
+ } else if (strcmp(argv[1], "spawn") == 0) {
+ // This is the start of Round 2.
+ // Expect Counts[dsoX] = 1, as this was the state at the end of Round 1.
+
+ int I;
+ pid_t child_pids[num_child_procs_to_spawn];
+ char *const child_argv[] = {argv[0], "nospawn", NULL};
+ char *const child_envp[] = {argv[2], NULL};
+ for (I = 0; I < num_child_procs_to_spawn; ++I) {
+ dso1(); // Counts[dsoX] += 2 * num_child_procs_to_spawn
+ dso2();
+
+ DEBUG("Spawning child with argv = {%s, %s, NULL} and envp = {%s, NULL}\n",
+ child_argv[0], child_argv[1], child_envp[0]);
+
+ int ret = posix_spawn(&child_pids[I], argv[0], NULL, NULL, child_argv,
+ child_envp);
+ if (ret != 0) {
+ fprintf(stderr, "Child %d could not be spawned: ret = %d, msg = %s\n",
+ I, ret, strerror(ret));
+ return 1;
+ }
+
+ DEBUG("Spawned child %d (pid = %d).\n", I, child_pids[I]);
+ }
+ for (I = 0; I < num_child_procs_to_spawn; ++I) {
+ dso1(); // Counts[dsoX] += num_child_procs_to_spawn
+ dso2();
+
+ int status;
+ waitpid(child_pids[I], &status, 0);
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+ fprintf(stderr, "Child %d did not exit with code 0.\n", I);
+ return 1;
+ }
+ }
+
+ // At the end of Round 2, we have:
+ // Counts[dsoX] = 1 + (2 * num_child_procs_to_spawn) + num_child_procs_to_spawn
+ // = 97
+
+ return 0;
+ }
+
+ return 1;
+}