[PGO] generate different version for FE instrumentation and IR level instrumentation profiles

[xur]

Summary

This patch checks __llvm_profile_ir_level and sets the right version in the generated profiles.
This is related to http://reviews.llvm.org/D15540.

[davidxl]

lib/profile/InstrProfiling.c

22

use macro LLVM_ATTRIBUTE_WEAK

[xur]

lib/profile/InstrProfiling.c

22

Macro LLVM_ATTRIBUTE_WEAK is defined in llvm/Support/Compiler.h. It seems to me we should include that header here (also that is a c++ header).
There are also other direct uses of attribute((weak)) in InstrProfilingFile.c.

[davidxl]

Please rebase your patch. The portability macro to be used is
COMPILER_RT_WEAK.

David

[xur]

Integrated David's comments.

[xur]

We now generate the profile version directly from the PGO instrumentation (based on Justin's suggestion).
This change is now obsolete.

lib/profile/InstrProfData.inc

#define INSTR_PROF_RAW_MAGIC_64 (uint64_t)255 << 56 | (uint64_t)'l' << 48 | \
         (uint64_t)'f' << 16 | (uint64_t)'r' << 8 | (uint64_t)129
 #define INSTR_PROF_RAW_MAGIC_32 (uint64_t)255 << 56 | (uint64_t)'l' << 48 | \
        (uint64_t)'p' << 40 | (uint64_t)'r' << 32 | (uint64_t)'o' << 24 |  \
         (uint64_t)'f' << 16 | (uint64_t)'R' << 8 | (uint64_t)129
 
 /* Raw profile format version. */
 #define INSTR_PROF_RAW_VERSION 2
 
+/* Profile version is always of type uint_64_t. Reserve the upper 8 bits in the
+ * version for other variants of profile. We set the lowest bit of the upper 8
+ * bits (i.e. bit 56) to 1 to indicate if this is an IR-level instrumentaiton
+ * generated profile, and 0 if this is a Clang FE generated profile.
+ */
+#define VARIANT_MASKS_ALL 0xff00000000000000ULL
+#define VARIANT_MASK_IR_PROF (0x1ULL << 56)
+#define GET_VERSION(V) ((V)&~VARIANT_MASKS_ALL)
+#define IR_LEVEL_PROF_VARNAME __llvm_profile_ir_level
+#define IR_LEVEL_PROF_STRINGFY(s) #s
+#define IR_LEVEL_PROF_STRING(s) IR_LEVEL_PROF_STRINGFY(s)
+
 /* Runtime section names and name strings.  */
 #define INSTR_PROF_DATA_SECT_NAME __llvm_prf_data
 #define INSTR_PROF_NAME_SECT_NAME __llvm_prf_names
 #define INSTR_PROF_CNTS_SECT_NAME __llvm_prf_cnts
 
 #define INSTR_PROF_DATA_SECT_NAME_STR \
         INSTR_PROF_QUOTE(INSTR_PROF_DATA_SECT_NAME)
 #define INSTR_PROF_NAME_SECT_NAME_STR \

lib/profile/InstrProfiling.c

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #define INSTR_PROF_VALUE_PROF_DATA
 #include "InstrProfData.inc"
 
 char *(*GetEnvHook)(const char *) = 0;
 
+/* IR level instrumentation declares a strong symbol and sets the value to 1. */
+COMPILER_RT_WEAK int IR_LEVEL_PROF_VARNAME = 0;
+
 COMPILER_RT_VISIBILITY uint64_t __llvm_profile_get_magic(void) {
   return sizeof(void *) == sizeof(uint64_t) ? (INSTR_PROF_RAW_MAGIC_64)
                                             : (INSTR_PROF_RAW_MAGIC_32);
 }
 
 /* Return the number of bytes needed to add to SizeInBytes to make it
  *   the result a multiple of 8.
  */
 COMPILER_RT_VISIBILITY uint8_t
 __llvm_profile_get_num_padding_bytes(uint64_t SizeInBytes) {
   return 7 & (sizeof(uint64_t) - SizeInBytes % sizeof(uint64_t));
 }
 
 COMPILER_RT_VISIBILITY uint64_t __llvm_profile_get_version(void) {
+  if (IR_LEVEL_PROF_VARNAME)
+    return INSTR_PROF_RAW_VERSION | VARIANT_MASK_IR_PROF;
   return INSTR_PROF_RAW_VERSION;
 }
 
 COMPILER_RT_VISIBILITY void __llvm_profile_reset_counters(void) {
   uint64_t *I = __llvm_profile_begin_counters();
   uint64_t *E = __llvm_profile_end_counters();
 
   memset(I, 0, sizeof(uint64_t) * (E - I));