[Profile] Allow online merging with debug info correlation.

When using debug info correlation, value profiling needs to be switched off.
So, we are only merging counter sections. In that case the existance of data
section is just used to provide an extra check in case of corrupted profile.

This patch performs counter merging by iterating the counter section by counter
size and add them together.

Reviewed By: ellis, MaskRay

Differential Revision: https://reviews.llvm.org/D157632

clang/lib/CodeGen/BackendUtil.cpp

@@ -102,7 +102,7 @@ namespace {
 
 // Default filename used for profile generation.
 std::string getDefaultProfileGenName() {
-  return DebugInfoCorrelate ? "default_%p.proflite" : "default_%m.profraw";
+  return DebugInfoCorrelate ? "default_%m.proflite" : "default_%m.profraw";
 }
 
 class EmitAssemblyHelper {

compiler-rt/lib/profile/InstrProfilingMerge.c

@@ -47,7 +47,6 @@ uint64_t lprofGetLoadModuleSignature(void) {
 COMPILER_RT_VISIBILITY
 int __llvm_profile_check_compatibility(const char *ProfileData,
                                        uint64_t ProfileSize) {
-  /* Check profile header only for now  */
   __llvm_profile_header *Header = (__llvm_profile_header *)ProfileData;
   __llvm_profile_data *SrcDataStart, *SrcDataEnd, *SrcData, *DstData;
   SrcDataStart =
@@ -102,13 +101,6 @@ static uintptr_t signextIfWin64(void *V) {
 COMPILER_RT_VISIBILITY
 int __llvm_profile_merge_from_buffer(const char *ProfileData,
                                      uint64_t ProfileSize) {
-  if (__llvm_profile_get_version() & VARIANT_MASK_DBG_CORRELATE) {
-    PROF_ERR(
-        "%s\n",
-        "Debug info correlation does not support profile merging at runtime. "
-        "Instead, merge raw profiles using the llvm-profdata tool.");
-    return 1;
-  }
   if (__llvm_profile_get_version() & VARIANT_MASK_TEMPORAL_PROF) {
     PROF_ERR("%s\n",
              "Temporal profiles do not support profile merging at runtime. "
@@ -118,7 +110,8 @@ int __llvm_profile_merge_from_buffer(const char *ProfileData,
 
   __llvm_profile_data *SrcDataStart, *SrcDataEnd, *SrcData, *DstData;
   __llvm_profile_header *Header = (__llvm_profile_header *)ProfileData;
-  char *SrcCountersStart;
+  char *SrcCountersStart, *DstCounter;
+  const char *SrcCountersEnd, *SrcCounter;
   const char *SrcNameStart;
   const char *SrcValueProfDataStart, *SrcValueProfData;
   uintptr_t CountersDelta = Header->CountersDelta;
@@ -128,14 +121,32 @@ int __llvm_profile_merge_from_buffer(const char *ProfileData,
                               Header->BinaryIdsSize);
   SrcDataEnd = SrcDataStart + Header->NumData;
   SrcCountersStart = (char *)SrcDataEnd;
-  SrcNameStart = SrcCountersStart +
-                 Header->NumCounters * __llvm_profile_counter_entry_size();
+  SrcCountersEnd = SrcCountersStart +
+                   Header->NumCounters * __llvm_profile_counter_entry_size();
+  SrcNameStart = SrcCountersEnd;
   SrcValueProfDataStart =
       SrcNameStart + Header->NamesSize +
       __llvm_profile_get_num_padding_bytes(Header->NamesSize);
   if (SrcNameStart < SrcCountersStart)
     return 1;
 
+  // Merge counters by iterating the entire counter section when debug info
+  // correlation is enabled.
+  if (__llvm_profile_get_version() & VARIANT_MASK_DBG_CORRELATE) {
+    for (SrcCounter = SrcCountersStart,
+        DstCounter = __llvm_profile_begin_counters();
+         SrcCounter < SrcCountersEnd;) {
+      if (__llvm_profile_get_version() & VARIANT_MASK_BYTE_COVERAGE) {
+        *DstCounter &= *SrcCounter;
+      } else {
+        *(uint64_t *)DstCounter += *(uint64_t *)SrcCounter;
+      }
+      SrcCounter += __llvm_profile_counter_entry_size();
+      DstCounter += __llvm_profile_counter_entry_size();
+    }
+    return 0;
+  }
+
   for (SrcData = SrcDataStart,
       DstData = (__llvm_profile_data *)__llvm_profile_begin_data(),
       SrcValueProfData = SrcValueProfDataStart;

compiler-rt/test/profile/Darwin/instrprof-debug-info-correlate.c

@@ -18,3 +18,23 @@
 // RUN: llvm-profdata merge -o %t.cov.normal.profdata %t.cov.profraw
 
 // RUN: diff <(llvm-profdata show --all-functions --counts %t.cov.normal.profdata) <(llvm-profdata show --all-functions --counts %t.cov.profdata)
+
+// Test debug info correlate with online merging.
+
+// RUN: env LLVM_PROFILE_FILE=%t-1.profraw %run %t.normal
+// RUN: env LLVM_PROFILE_FILE=%t-2.profraw %run %t.normal
+// RUN: llvm-profdata merge -o %t.normal.profdata %t-1.profraw %t-2.profraw
+
+// RUN: rm -rf %t.profdir && mkdir %t.profdir
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.proflite %run %t
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.proflite %run %t
+// RUN: llvm-profdata merge -o %t.profdata --debug-info=%t.dSYM %t.profdir/
+
+// RUN: diff <(llvm-profdata show --all-functions --counts %t.normal.profdata) <(llvm-profdata show --all-functions --counts %t.profdata)
+
+// RUN: rm -rf %t.profdir && mkdir %t.profdir
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.cov.proflite %run %t.cov
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.cov.proflite %run %t.cov
+// RUN: llvm-profdata merge -o %t.cov.profdata --debug-info=%t.cov.dSYM %t.profdir/
+
+// RUN: diff <(llvm-profdata show --all-functions --counts %t.cov.normal.profdata) <(llvm-profdata show --all-functions --counts %t.cov.profdata)

compiler-rt/test/profile/Linux/instrprof-debug-info-correlate.c

@@ -24,3 +24,23 @@
 // RUN: llvm-profdata merge -o %t.cov.normal.profdata %t.cov.profraw
 
 // RUN: diff <(llvm-profdata show --all-functions --counts %t.cov.normal.profdata) <(llvm-profdata show --all-functions --counts %t.cov.profdata)
+
+// Test debug info correlate with online merging.
+
+// RUN: env LLVM_PROFILE_FILE=%t-1.profraw %run %t.normal
+// RUN: env LLVM_PROFILE_FILE=%t-2.profraw %run %t.normal
+// RUN: llvm-profdata merge -o %t.normal.profdata %t-1.profraw %t-2.profraw
+
+// RUN: rm -rf %t.profdir && mkdir %t.profdir
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.proflite %run %t
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.proflite %run %t
+// RUN: llvm-profdata merge -o %t.profdata --debug-info=%t %t.profdir/
+
+// RUN: diff <(llvm-profdata show --all-functions --counts %t.normal.profdata) <(llvm-profdata show --all-functions --counts %t.profdata)
+
+// RUN: rm -rf %t.profdir && mkdir %t.profdir
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.cov.proflite %run %t.cov
+// RUN: env LLVM_PROFILE_FILE=%t.profdir/%m.cov.proflite %run %t.cov
+// RUN: llvm-profdata merge -o %t.cov.profdata --debug-info=%t.cov %t.profdir/
+
+// RUN: diff <(llvm-profdata show --all-functions --counts %t.cov.normal.profdata) <(llvm-profdata show --all-functions --counts %t.cov.profdata)

compiler-rt/test/profile/instrprof-merge-empty-data.test

@@ -0,0 +1,14 @@
+// Test online merging with empty data section.
+// RUN: rm -rf %t.dir && split-file %s %t.dir && cd %t.dir
+// RUN: %clangxx_profgen -fcoverage-mapping -o %t main.c -fprofile-list=funlist
+// RUN: env LLVM_PROFILE_FILE='a%m.profraw' %t
+// RUN: env LLVM_PROFILE_FILE='a%m.profraw' %t 2>&1 | FileCheck %s --allow-empty
+
+// CHECK-NOT: LLVM Profile Error
+
+//--- main.c
+int main() {}
+
+//--- funlist
+[clang]
+default:skip

compiler-rt/test/profile/instrprof-merge-error.c

@@ -1,11 +1,5 @@
 // RUN: rm -rf %t; mkdir %t
 
-// RUN: %clang_pgogen -o %t/dbg -g -mllvm --debug-info-correlate -mllvm --disable-vp=true %s
-// RUN: env LLVM_PROFILE_FILE=%t/dbg_%m.profdata %run %t/dbg 2>&1 | count 0
-// RUN: env LLVM_PROFILE_FILE=%t/dbg_%m.profdata %run %t/dbg 2>&1 | FileCheck %s --check-prefix=DBG
-
-// DBG: Debug info correlation does not support profile merging at runtime.
-
 // RUN: %clang_pgogen -o %t/timeprof -mllvm -pgo-temporal-instrumentation %s
 // RUN: env LLVM_PROFILE_FILE=%t/timeprof_%m.profdata %run %t/timeprof 2>&1 | count 0
 // RUN: env LLVM_PROFILE_FILE=%t/timeprof_%m.profdata %run %t/timeprof 2>&1 | FileCheck %s --check-prefix=TIMEPROF