Order File Instrumentation: dump the data in compiler-rt (Make it work for Linux/Windows etc)

[manmanren]

Summary

The diff D57530 was accepted and I landed it as r355343. It works fine for Darwin, but caused build breakages for Linux/Windows etc.
This diff adds support for these platforms.

[manmanren]

lib/profile/InstrProfilingPlatformLinux.c

67

I am getting undefined reference to `start_llvm_orderfile'. Not quite know where we define these symbols for PROF_CNTS etc.

lib/profile/InstrProfilingPlatformOther.c

88

Not sure what I should do for PlatformOther :[

lib/profile/InstrProfilingPlatformWindows.c

32

The windows implementation seems to be working at r355357 (http://lab.llvm.org:8011/builders/sanitizer-windows/builds/42814).

[davidxl]

lib/profile/InstrProfilingPlatformLinux.c

67

The cnt, data symbols are created in the related sections. Those symbols are created during instrumentation lowering -- see lib/Transforms/Instrumentation/InstrProfiling.cc

lib/profile/InstrProfilingPlatformOther.c

88

For these platforms, you need to add interface to register symbols in orderFile section, and this new interface just track the start and end of the section. The register functions are called during startup. See also lowering pass that generates call to register functions.

[manmanren]

lib/profile/InstrProfilingPlatformLinux.c

67

I can't find INSTR_PROF_SECT_START or "__start_" in InstrProfiling.cpp. Can you provide a bit more info? Thanks!

lib/profile/InstrProfilingPlatformOther.c

88

Is __llvm_profile_register_function the one? Should we add a new function for orderFile section?

[davidxl]

lib/profile/InstrProfilingPlatformLinux.c

67

The start_xxx and stop_xxx symbols are automatically generated by the linker to reference to the start end stop address of section named 'xxx'. Compiler just need to put things into 'xxx':

CounterPtr->setSection(

getInstrProfSectionName(IPSK_cnts, TT.getObjectFormat()));

lib/profile/InstrProfilingPlatformOther.c

88

yes, there is also __llvm_profile_register_names_function for name sections.

emit the registration call in void InstrProfiling::emitRegistration() {..}

[manmanren]

Thanks!

Manman

lib/profile/InstrProfilingPlatformLinux.c

67

In InstrOrderFile.cpp, we have this already:

OrderFileBuffer->setSection(
    getInstrProfSectionName(IPSK_orderfile, TT.getObjectFormat()));

This actually works locally on my Linux machine.

The buildbot error message was
/home/buildbots/ppc64be-clang-multistage-test/clang-ppc64be-multistage/stage2/lib/clang/9.0.0/lib/linux/libclang_rt.profile-powerpc64.a(InstrProfilingPlatformLinux.c.o): In function `llvm_profile_begin_orderfile':
InstrProfilingPlatformLinux.c:(.text.llvm_profile_begin_orderfile+0x2): undefined reference to `start_llvm_orderfile'
InstrProfilingPlatformLinux.c:(.text.llvm_profile_begin_orderfile+0x6): undefined reference to `start___llvm_orderfile'
/bin/ld: /home/buildbots/ppc64be-clang-multistage-test/clang-ppc64be-multistage/stage2/projects/compiler-rt/test/profile/Profile-powerpc64/Posix/Output/instrprof-dlopen.test.tmp.d/func.shared: hidden symbol `start_llvm_orderfile' isn't defined
/bin/ld: final link failed: Bad value
clang-9: error: linker command failed with exit code 1 (use -v to see invocation)

[davidxl]

lib/profile/InstrProfilingPlatformLinux.c

41

When the runtime is linked in but no instrumentation is done, you will need to add a dummy data for order file section here.

lib/profile/InstrProfData.inc

INSTR_PROF_SECT_ENTRY(IPSK_vals, \
                       INSTR_PROF_QUOTE(INSTR_PROF_VALS_COMMON), \
                       INSTR_PROF_VALS_COFF, "__DATA,")
 INSTR_PROF_SECT_ENTRY(IPSK_vnodes, \
                       INSTR_PROF_QUOTE(INSTR_PROF_VNODES_COMMON), \
                       INSTR_PROF_VNODES_COFF, "__DATA,")
 INSTR_PROF_SECT_ENTRY(IPSK_covmap, \
                       INSTR_PROF_QUOTE(INSTR_PROF_COVMAP_COMMON), \
                       INSTR_PROF_COVMAP_COFF, "__LLVM_COV,")
+INSTR_PROF_SECT_ENTRY(IPSK_orderfile, \
+                      INSTR_PROF_QUOTE(INSTR_PROF_ORDERFILE_COMMON), \
+                      INSTR_PROF_QUOTE(INSTR_PROF_ORDERFILE_COFF), "__DATA,")
 
 #undef INSTR_PROF_SECT_ENTRY
 #endif
 
 
 #ifdef INSTR_PROF_VALUE_PROF_DATA
 #define INSTR_PROF_DATA_DEFINED
 

 /* section name strings common to all targets other
    than WIN32 */
 #define INSTR_PROF_DATA_COMMON __llvm_prf_data
 #define INSTR_PROF_NAME_COMMON __llvm_prf_names
 #define INSTR_PROF_CNTS_COMMON __llvm_prf_cnts
 #define INSTR_PROF_VALS_COMMON __llvm_prf_vals
 #define INSTR_PROF_VNODES_COMMON __llvm_prf_vnds
 #define INSTR_PROF_COVMAP_COMMON __llvm_covmap
+#define INSTR_PROF_ORDERFILE_COMMON __llvm_orderfile
 /* Windows section names. Because these section names contain dollar characters,
  * they must be quoted.
  */
 #define INSTR_PROF_DATA_COFF ".lprfd$M"
 #define INSTR_PROF_NAME_COFF ".lprfn$M"
 #define INSTR_PROF_CNTS_COFF ".lprfc$M"
 #define INSTR_PROF_VALS_COFF ".lprfv$M"
 #define INSTR_PROF_VNODES_COFF ".lprfnd$M"
 #define INSTR_PROF_COVMAP_COFF ".lcovmap$M"
+#define INSTR_PROF_ORDERFILE_COFF ".lorderfile$M"
 
 #ifdef _WIN32
 /* Runtime section names and name strings.  */
 #define INSTR_PROF_DATA_SECT_NAME INSTR_PROF_DATA_COFF
 #define INSTR_PROF_NAME_SECT_NAME INSTR_PROF_NAME_COFF
 #define INSTR_PROF_CNTS_SECT_NAME INSTR_PROF_CNTS_COFF
 /* Array of pointers. Each pointer points to a list
  * of value nodes associated with one value site.
  */
 #define INSTR_PROF_VALS_SECT_NAME INSTR_PROF_VALS_COFF
 /* Value profile nodes section. */
 #define INSTR_PROF_VNODES_SECT_NAME INSTR_PROF_VNODES_COFF
 #define INSTR_PROF_COVMAP_SECT_NAME INSTR_PROF_COVMAP_COFF
+#define INSTR_PROF_ORDERFILE_SECT_NAME INSTR_PROF_ORDERFILE_COFF
 #else
 /* Runtime section names and name strings.  */
 #define INSTR_PROF_DATA_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_DATA_COMMON)
 #define INSTR_PROF_NAME_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_NAME_COMMON)
 #define INSTR_PROF_CNTS_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_CNTS_COMMON)
 /* Array of pointers. Each pointer points to a list
  * of value nodes associated with one value site.
  */
 #define INSTR_PROF_VALS_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_VALS_COMMON)
 /* Value profile nodes section. */
 #define INSTR_PROF_VNODES_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_VNODES_COMMON)
 #define INSTR_PROF_COVMAP_SECT_NAME INSTR_PROF_QUOTE(INSTR_PROF_COVMAP_COMMON)
+/* Order file instrumentation. */
+#define INSTR_PROF_ORDERFILE_SECT_NAME                                         \
+  INSTR_PROF_QUOTE(INSTR_PROF_ORDERFILE_COMMON)
 #endif
 
+#define INSTR_PROF_ORDERFILE_BUFFER_NAME _llvm_order_file_buffer
+#define INSTR_PROF_ORDERFILE_BUFFER_NAME_STR                                   \
+  INSTR_PROF_QUOTE(INSTR_PROF_ORDERFILE_BUFFER_NAME)
+#define INSTR_PROF_ORDERFILE_BUFFER_IDX_NAME _llvm_order_file_buffer_idx
+#define INSTR_PROF_ORDERFILE_BUFFER_IDX_NAME_STR                               \
+  INSTR_PROF_QUOTE(INSTR_PROF_ORDERFILE_BUFFER_IDX_NAME)
+
 /* Macros to define start/stop section symbol for a given
  * section on Linux. For instance
  * INSTR_PROF_SECT_START(INSTR_PROF_DATA_SECT_NAME) will
  * expand to __start___llvm_prof_data
  */
 #define INSTR_PROF_SECT_START(Sect) \
         INSTR_PROF_CONCAT(__start_,Sect)
 #define INSTR_PROF_SECT_STOP(Sect) \
typedef struct InstrProfValueData {
   /* Profiled value. */
   uint64_t Value;
   /* Number of times the value appears in the training run. */
   uint64_t Count;
 } InstrProfValueData;
 
 #endif /* INSTR_PROF_DATA_INC */
 
+#ifndef INSTR_ORDER_FILE_INC
+// The maximal # of functions: 128*1024 (the buffer size will be 128*4 KB).
+#define INSTR_ORDER_FILE_BUFFER_SIZE 131072
+#define INSTR_ORDER_FILE_BUFFER_BITS 17
+#define INSTR_ORDER_FILE_BUFFER_MASK 0x1ffff
+#endif /* INSTR_ORDER_FILE_INC */
 #else
 #undef INSTR_PROF_DATA_DEFINED
 #endif

lib/profile/InstrProfiling.h

 const __llvm_profile_data *__llvm_profile_begin_data(void);
 const __llvm_profile_data *__llvm_profile_end_data(void);
 const char *__llvm_profile_begin_names(void);
 const char *__llvm_profile_end_names(void);
 uint64_t *__llvm_profile_begin_counters(void);
 uint64_t *__llvm_profile_end_counters(void);
 ValueProfNode *__llvm_profile_begin_vnodes();
 ValueProfNode *__llvm_profile_end_vnodes();
+uint32_t *__llvm_profile_begin_orderfile();
 
 /*!
  * \brief Clear profile counters to zero.
  *
  */
 void __llvm_profile_reset_counters(void);
 
 /*!

  * Writes to the file with the last name given to \a *
  * __llvm_profile_set_filename(),
  * or if it hasn't been called, the \c LLVM_PROFILE_FILE environment variable,
  * or if that's not set, the last name set to INSTR_PROF_PROFILE_NAME_VAR,
  * or if that's not set,  \c "default.profraw".
  */
 int __llvm_profile_write_file(void);
 
+int __llvm_orderfile_write_file(void);
 /*!
  * \brief this is a wrapper interface to \c __llvm_profile_write_file.
  * After this interface is invoked, a arleady dumped flag will be set
  * so that profile won't be dumped again during program exit. 
  * Invocation of interface __llvm_profile_reset_counters will clear
  * the flag. This interface is designed to be used to collect profile
  * data from user selected hot regions. The use model is
  *      __llvm_profile_reset_counters();
  *      ... hot region 1
  *      __llvm_profile_dump();
  *      .. some other code
  *      __llvm_profile_reset_counters();
  *       ... hot region 2
  *      __llvm_profile_dump();
  *
  *  It is expected that on-line profile merging is on with \c %m specifier
  *  used in profile filename . If merging is  not turned on, user is expected
  *  to invoke __llvm_profile_set_filename  to specify different profile names
  *  for different regions before dumping to avoid profile write clobbering.
  */
 int __llvm_profile_dump(void);
 
+int __llvm_orderfile_dump(void);
+
 /*!
  * \brief Set the filename for writing instrumentation data.
  *
  * Sets the filename to be used for subsequent calls to
  * \a __llvm_profile_write_file().
  *
  * \c Name is not copied, so it must remain valid.  Passing NULL resets the
  * filename logic to the default behaviour.

lib/profile/InstrProfilingFile.c

for (I = 0; I < NumIOVecs; I++) {
     } else {
       if (fseek(File, IOVecs[I].ElmSize * IOVecs[I].NumElm, SEEK_CUR) == -1)
         return 1;
     }
   }
   return 0;
 }
 
+/* TODO: make buffer size controllable by an internal option, and compiler can pass the size
+   to runtime via a variable. */
+static uint32_t orderFileWriter(FILE *File, const uint32_t *DataStart) {
+  if (fwrite(DataStart, sizeof(uint32_t), INSTR_ORDER_FILE_BUFFER_SIZE, File) !=
+      INSTR_ORDER_FILE_BUFFER_SIZE)
+    return 1;
+  return 0;
+}
+
 static void initFileWriter(ProfDataWriter *This, FILE *File) {
   This->Write = fileWriter;
   This->WriterCtx = File;
 }
 
 COMPILER_RT_VISIBILITY ProfBufferIO *
 lprofCreateBufferIOInternal(void *File, uint32_t BufferSz) {
   FreeHook = &free;
static int writeFile(const char *OutputName) {
   ProfDataWriter fileWriter;
   initFileWriter(&fileWriter, OutputFile);
   RetVal = lprofWriteData(&fileWriter, lprofGetVPDataReader(), MergeDone);
 
   fclose(OutputFile);
   return RetVal;
 }
 
+/* Write order data to file \c OutputName.  */
+static int writeOrderFile(const char *OutputName) {
+  int RetVal;
+  FILE *OutputFile;
+
+  OutputFile = fopen(OutputName, "w");
+
+  if (!OutputFile) {
+    PROF_WARN("can't open file with mode ab: %s\n", OutputName);
+    return -1;
+  }
+
+  FreeHook = &free;
+  setupIOBuffer();
+  const uint32_t *DataBegin = __llvm_profile_begin_orderfile();
+  RetVal = orderFileWriter(OutputFile, DataBegin);
+
+  fclose(OutputFile);
+  return RetVal;
+}
+
 static void truncateCurrentFile(void) {
   const char *Filename;
   char *FilenameBuf;
   FILE *File;
   int Length;
 
   Length = getCurFilenameLength();
   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
PROF_WARN("Later invocation of __llvm_profile_dump can lead to clobbering "
               " of previously dumped profile data : %s. Either use %%m "
               "in profile name or change profile name before dumping.\n",
               "online profile merging is not on");
   int rc = __llvm_profile_write_file();
   lprofSetProfileDumped();
   return rc;
 }
 
+/* Order file data will be saved in a file with suffx .order. */
+static const char *OrderFileSuffix = ".order";
+
+COMPILER_RT_VISIBILITY
+int __llvm_orderfile_write_file(void) {
+  int rc, Length, LengthBeforeAppend, SuffixLength;
+  const char *Filename;
+  char *FilenameBuf;
+  int PDeathSig = 0;
+
+  SuffixLength = strlen(OrderFileSuffix);
+  Length = getCurFilenameLength() + SuffixLength;
+  FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
+  Filename = getCurFilename(FilenameBuf, 1);
+
+  /* Check the filename. */
+  if (!Filename) {
+    PROF_ERR("Failed to write file : %s\n", "Filename not set");
+    return -1;
+  }
+
+  /* Append order file suffix */
+  LengthBeforeAppend = strlen(Filename);
+  memcpy(FilenameBuf + LengthBeforeAppend, OrderFileSuffix, SuffixLength);
+  FilenameBuf[LengthBeforeAppend + SuffixLength] = '\0';
+
+  /* Check if there is llvm/runtime version mismatch.  */
+  if (GET_VERSION(__llvm_profile_get_version()) != INSTR_PROF_RAW_VERSION) {
+    PROF_ERR("Runtime and instrumentation version mismatch : "
+             "expected %d, but get %d\n",
+             INSTR_PROF_RAW_VERSION,
+             (int)GET_VERSION(__llvm_profile_get_version()));
+    return -1;
+  }
+
+  // Temporarily suspend getting SIGKILL when the parent exits.
+  PDeathSig = lprofSuspendSigKill();
+
+  /* Write order data to the file. */
+  rc = writeOrderFile(Filename);
+  if (rc)
+    PROF_ERR("Failed to write file \"%s\": %s\n", Filename, strerror(errno));
+
+  // Restore SIGKILL.
+  if (PDeathSig == 1)
+    lprofRestoreSigKill();
+
+  return rc;
+}
+
+COMPILER_RT_VISIBILITY
+int __llvm_orderfile_dump(void) {
+  int rc = __llvm_orderfile_write_file();
+  return rc;
+}
+
 static void writeFileWithoutReturn(void) { __llvm_profile_write_file(); }
 
 COMPILER_RT_VISIBILITY
 int __llvm_profile_register_write_file_atexit(void) {
   static int HasBeenRegistered = 0;
 
   if (HasBeenRegistered)
     return 0;
 
   lprofSetupValueProfiler();
 
   HasBeenRegistered = 1;
   return atexit(writeFileWithoutReturn);
 }
 
 #endif

lib/profile/InstrProfilingPlatformDarwin.c

 COMPILER_RT_VISIBILITY
 extern char NamesEnd __asm("section$end$__DATA$" INSTR_PROF_NAME_SECT_NAME);
 COMPILER_RT_VISIBILITY
 extern uint64_t
     CountersStart __asm("section$start$__DATA$" INSTR_PROF_CNTS_SECT_NAME);
 COMPILER_RT_VISIBILITY
 extern uint64_t
     CountersEnd __asm("section$end$__DATA$" INSTR_PROF_CNTS_SECT_NAME);
+COMPILER_RT_VISIBILITY
+extern uint32_t
+    OrderFileStart __asm("section$start$__DATA$" INSTR_PROF_ORDERFILE_SECT_NAME);
 
 COMPILER_RT_VISIBILITY
 extern ValueProfNode
     VNodesStart __asm("section$start$__DATA$" INSTR_PROF_VNODES_SECT_NAME);
 COMPILER_RT_VISIBILITY
 extern ValueProfNode
     VNodesEnd __asm("section$end$__DATA$" INSTR_PROF_VNODES_SECT_NAME);
 
 COMPILER_RT_VISIBILITY
 const __llvm_profile_data *__llvm_profile_begin_data(void) {
   return &DataStart;
 }
 COMPILER_RT_VISIBILITY
 const __llvm_profile_data *__llvm_profile_end_data(void) { return &DataEnd; }
 COMPILER_RT_VISIBILITY
 const char *__llvm_profile_begin_names(void) { return &NamesStart; }
 COMPILER_RT_VISIBILITY
 const char *__llvm_profile_end_names(void) { return &NamesEnd; }
 COMPILER_RT_VISIBILITY
 uint64_t *__llvm_profile_begin_counters(void) { return &CountersStart; }
 COMPILER_RT_VISIBILITY
 uint64_t *__llvm_profile_end_counters(void) { return &CountersEnd; }
+COMPILER_RT_VISIBILITY
+uint32_t *__llvm_profile_begin_orderfile(void) { return &OrderFileStart; }
 
 COMPILER_RT_VISIBILITY
 ValueProfNode *__llvm_profile_begin_vnodes(void) {
   return &VNodesStart;
 }
 COMPILER_RT_VISIBILITY
 ValueProfNode *__llvm_profile_end_vnodes(void) { return &VNodesEnd; }
 
 COMPILER_RT_VISIBILITY ValueProfNode *CurrentVNode = &VNodesStart;
 COMPILER_RT_VISIBILITY ValueProfNode *EndVNode = &VNodesEnd;
 #endif

lib/profile/InstrProfilingPlatformLinux.c

 #include "InstrProfiling.h"
 
 #define PROF_DATA_START INSTR_PROF_SECT_START(INSTR_PROF_DATA_COMMON)
 #define PROF_DATA_STOP INSTR_PROF_SECT_STOP(INSTR_PROF_DATA_COMMON)
 #define PROF_NAME_START INSTR_PROF_SECT_START(INSTR_PROF_NAME_COMMON)
 #define PROF_NAME_STOP INSTR_PROF_SECT_STOP(INSTR_PROF_NAME_COMMON)
 #define PROF_CNTS_START INSTR_PROF_SECT_START(INSTR_PROF_CNTS_COMMON)
 #define PROF_CNTS_STOP INSTR_PROF_SECT_STOP(INSTR_PROF_CNTS_COMMON)
+#define PROF_ORDERFILE_START INSTR_PROF_SECT_START(INSTR_PROF_ORDERFILE_COMMON)
 #define PROF_VNODES_START INSTR_PROF_SECT_START(INSTR_PROF_VNODES_COMMON)
 #define PROF_VNODES_STOP INSTR_PROF_SECT_STOP(INSTR_PROF_VNODES_COMMON)
 
 /* Declare section start and stop symbols for various sections
  * generated by compiler instrumentation.
  */
 extern __llvm_profile_data PROF_DATA_START COMPILER_RT_VISIBILITY;
 extern __llvm_profile_data PROF_DATA_STOP COMPILER_RT_VISIBILITY;
 extern uint64_t PROF_CNTS_START COMPILER_RT_VISIBILITY;
 extern uint64_t PROF_CNTS_STOP COMPILER_RT_VISIBILITY;
+extern uint32_t PROF_ORDERFILE_START COMPILER_RT_VISIBILITY;
 extern char PROF_NAME_START COMPILER_RT_VISIBILITY;
 extern char PROF_NAME_STOP COMPILER_RT_VISIBILITY;
 extern ValueProfNode PROF_VNODES_START COMPILER_RT_VISIBILITY;
 extern ValueProfNode PROF_VNODES_STOP COMPILER_RT_VISIBILITY;
 
 /* Add dummy data to ensure the section is always created. */
 __llvm_profile_data
     __prof_data_sect_data[0] COMPILER_RT_SECTION(INSTR_PROF_DATA_SECT_NAME);
 uint64_t
     __prof_cnts_sect_data[0] COMPILER_RT_SECTION(INSTR_PROF_CNTS_SECT_NAME);
 char __prof_nms_sect_data[0] COMPILER_RT_SECTION(INSTR_PROF_NAME_SECT_NAME);
 ValueProfNode __prof_vnodes_sect_data[0] COMPILER_RT_SECTION(INSTR_PROF_VNODES_SECT_NAME);
 
 COMPILER_RT_VISIBILITY const __llvm_profile_data *
 __llvm_profile_begin_data(void) {
   return &PROF_DATA_START;
COMPILER_RT_VISIBILITY const char *__llvm_profile_end_names(void) {
   return &PROF_NAME_STOP;
 }
 COMPILER_RT_VISIBILITY uint64_t *__llvm_profile_begin_counters(void) {
   return &PROF_CNTS_START;
 }
 COMPILER_RT_VISIBILITY uint64_t *__llvm_profile_end_counters(void) {
   return &PROF_CNTS_STOP;
 }
+COMPILER_RT_VISIBILITY uint32_t *__llvm_profile_begin_orderfile(void) {
+  return &PROF_ORDERFILE_START;
+}
 
 COMPILER_RT_VISIBILITY ValueProfNode *
 __llvm_profile_begin_vnodes(void) {
   return &PROF_VNODES_START;
 }
 COMPILER_RT_VISIBILITY ValueProfNode *__llvm_profile_end_vnodes(void) {
   return &PROF_VNODES_STOP;
 }
 COMPILER_RT_VISIBILITY ValueProfNode *CurrentVNode = &PROF_VNODES_START;
 COMPILER_RT_VISIBILITY ValueProfNode *EndVNode = &PROF_VNODES_STOP;
 
 #endif

lib/profile/InstrProfilingPlatformOther.c

 #include "InstrProfiling.h"
 
 static const __llvm_profile_data *DataFirst = NULL;
 static const __llvm_profile_data *DataLast = NULL;
 static const char *NamesFirst = NULL;
 static const char *NamesLast = NULL;
 static uint64_t *CountersFirst = NULL;
 static uint64_t *CountersLast = NULL;
+static uint32_t *OrderFileFirst = NULL;
 
 static const void *getMinAddr(const void *A1, const void *A2) {
   return A1 < A2 ? A1 : A2;
 }
 
 static const void *getMaxAddr(const void *A1, const void *A2) {
   return A1 > A2 ? A1 : A2;
 }

 COMPILER_RT_VISIBILITY
 const char *__llvm_profile_begin_names(void) { return NamesFirst; }
 COMPILER_RT_VISIBILITY
 const char *__llvm_profile_end_names(void) { return NamesLast; }
 COMPILER_RT_VISIBILITY
 uint64_t *__llvm_profile_begin_counters(void) { return CountersFirst; }
 COMPILER_RT_VISIBILITY
 uint64_t *__llvm_profile_end_counters(void) { return CountersLast; }
+/* TODO: correctly set up OrderFileFirst. */
+COMPILER_RT_VISIBILITY
+uint32_t *__llvm_profile_begin_orderfile(void) { return OrderFileFirst; }
 
 COMPILER_RT_VISIBILITY
 ValueProfNode *__llvm_profile_begin_vnodes(void) {
   return 0;
 }
 COMPILER_RT_VISIBILITY
 ValueProfNode *__llvm_profile_end_vnodes(void) { return 0; }
 
 COMPILER_RT_VISIBILITY ValueProfNode *CurrentVNode = 0;
 COMPILER_RT_VISIBILITY ValueProfNode *EndVNode = 0;
 
 #endif

lib/profile/InstrProfilingPlatformWindows.c

 #pragma section(".lprfn$A", read)
 #pragma section(".lprfn$Z", read)
 
 /* Allocate read-write section bounds. */
 #pragma section(".lprfd$A", read, write)
 #pragma section(".lprfd$Z", read, write)
 #pragma section(".lprfc$A", read, write)
 #pragma section(".lprfc$Z", read, write)
+#pragma section(".lorderfile$A", read, write)
 #pragma section(".lprfnd$A", read, write)
 #pragma section(".lprfnd$Z", read, write)
 #endif
 
 __llvm_profile_data COMPILER_RT_SECTION(".lprfd$A") DataStart = {0};
 __llvm_profile_data COMPILER_RT_SECTION(".lprfd$Z") DataEnd = {0};
 
 const char COMPILER_RT_SECTION(".lprfn$A") NamesStart = '\0';
 const char COMPILER_RT_SECTION(".lprfn$Z") NamesEnd = '\0';
 
 uint64_t COMPILER_RT_SECTION(".lprfc$A") CountersStart;
 uint64_t COMPILER_RT_SECTION(".lprfc$Z") CountersEnd;
+uint32_t COMPILER_RT_SECTION(".lorderfile$A") OrderFileStart;
 
 ValueProfNode COMPILER_RT_SECTION(".lprfnd$A") VNodesStart;
 ValueProfNode COMPILER_RT_SECTION(".lprfnd$Z") VNodesEnd;
 
 const __llvm_profile_data *__llvm_profile_begin_data(void) {
   return &DataStart + 1;
 }
 const __llvm_profile_data *__llvm_profile_end_data(void) { return &DataEnd; }
 
 const char *__llvm_profile_begin_names(void) { return &NamesStart + 1; }
 const char *__llvm_profile_end_names(void) { return &NamesEnd; }
 
 uint64_t *__llvm_profile_begin_counters(void) { return &CountersStart + 1; }
 uint64_t *__llvm_profile_end_counters(void) { return &CountersEnd; }
+uint32_t *__llvm_profile_begin_orderfile(void) { return &OrderFileStart; }
 
 ValueProfNode *__llvm_profile_begin_vnodes(void) { return &VNodesStart + 1; }
 ValueProfNode *__llvm_profile_end_vnodes(void) { return &VNodesEnd; }
 
 ValueProfNode *CurrentVNode = &VNodesStart + 1;
 ValueProfNode *EndVNode = &VNodesEnd;
 
 #endif