profile: Add low level versions of profile buffer functions

On Darwin, compiler_rt uses magic linker symbols to find the profile
counters in the __DATA segment.  This is a reasonable method for
normal, hosted, userspace programs.  However programs with custom
memory layouts, such as the kernel, will need to tell compiler_rt
explicitly where to find these sections.

Patch by Lawrence D'Anna. Thanks!

llvm-svn: 223840

1 files changed, 39 insertions, 4 deletions

diff --git a/compiler-rt/lib/profile/InstrProfilingBuffer.c b/compiler-rt/lib/profile/InstrProfilingBuffer.c
index 3351b07ba6f..3c429c8a85e 100644
--- a/compiler-rt/lib/profile/InstrProfilingBuffer.c
+++ b/compiler-rt/lib/profile/InstrProfilingBuffer.c
@@ -8,17 +8,38 @@
 \*===----------------------------------------------------------------------===*/
 
 #include "InstrProfiling.h"
+#include "InstrProfilingInternal.h"
+
 #include <string.h>
 
 __attribute__((visibility("hidden")))
 uint64_t __llvm_profile_get_size_for_buffer(void) {
+  const __llvm_profile_data *DataBegin = __llvm_profile_begin_data();
+  const __llvm_profile_data *DataEnd = __llvm_profile_end_data();
+  const uint64_t *CountersBegin = __llvm_profile_begin_counters();
+  const uint64_t *CountersEnd = __llvm_profile_end_counters();
+  const char *NamesBegin = __llvm_profile_begin_names();
+  const char *NamesEnd = __llvm_profile_end_names();
+
+  return __llvm_profile_get_size_for_buffer_internal(
+      DataBegin, DataEnd, CountersBegin, CountersEnd, NamesBegin, NamesEnd);
+}
+
+#define PROFILE_RANGE_SIZE(Range) (Range##End - Range##Begin)
+
+__attribute__((visibility("hidden")))
+uint64_t __llvm_profile_get_size_for_buffer_internal(
+        const __llvm_profile_data *DataBegin,
+        const __llvm_profile_data *DataEnd, const uint64_t *CountersBegin,
+        const uint64_t *CountersEnd, const char *NamesBegin,
+        const char *NamesEnd) {
   /* Match logic in __llvm_profile_write_buffer(). */
-  const uint64_t NamesSize = PROFILE_RANGE_SIZE(names) * sizeof(char);
+  const uint64_t NamesSize = PROFILE_RANGE_SIZE(Names) * sizeof(char);
   const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
   return sizeof(uint64_t) * PROFILE_HEADER_SIZE +
-     PROFILE_RANGE_SIZE(data) * sizeof(__llvm_profile_data) +
-     PROFILE_RANGE_SIZE(counters) * sizeof(uint64_t) +
-     NamesSize + Padding;
+      PROFILE_RANGE_SIZE(Data) * sizeof(__llvm_profile_data) +
+      PROFILE_RANGE_SIZE(Counters) * sizeof(uint64_t) +
+      NamesSize + Padding;
 }
 
 __attribute__((visibility("hidden")))
@@ -33,6 +54,20 @@ int __llvm_profile_write_buffer(char *Buffer) {
   const char *NamesBegin = __llvm_profile_begin_names();
   const char *NamesEnd   = __llvm_profile_end_names();
 
+  return __llvm_profile_write_buffer_internal(Buffer, DataBegin, DataEnd,
+                                              CountersBegin, CountersEnd,
+                                              NamesBegin, NamesEnd);
+}
+
+__attribute__((visibility("hidden")))
+int __llvm_profile_write_buffer_internal(
+    char *Buffer, const __llvm_profile_data *DataBegin,
+    const __llvm_profile_data *DataEnd, const uint64_t *CountersBegin,
+    const uint64_t *CountersEnd, const char *NamesBegin, const char *NamesEnd) {
+  /* Match logic in __llvm_profile_get_size_for_buffer().
+   * Match logic in __llvm_profile_write_file().
+   */
+
   /* Calculate size of sections. */
   const uint64_t DataSize = DataEnd - DataBegin;
   const uint64_t CountersSize = CountersEnd - CountersBegin;