[clang] [InstrProf] Add frontend temporal profiling flag (PR #122385)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ellis Hoag (ellishg)

<details>
<summary>Changes</summary>

As discussed in https://github.com/llvm/llvm-project/pull/121514 add the frontent flag `-fprofile-generate-temporal-instrumentation` to enable temporal profiling (https://discourse.llvm.org/t/rfc-temporal-profiling-extension-for-irpgo/68068) as a replacement for `-forder-file-instrumentation` (https://discourse.llvm.org/t/deprecate-forder-file-instrumentation-in-favor-of-temporal-profiling/83903)

---
Full diff: https://github.com/llvm/llvm-project/pull/122385.diff


4 Files Affected:

- (modified) clang/include/clang/Driver/Options.td (+4-1) 
- (modified) clang/lib/Driver/ToolChains/Clang.cpp (+10-1) 
- (modified) clang/test/Driver/clang_f_opts.c (+1-1) 
- (added) clang/test/Driver/fprofile-generate-temporal-instrumentation.c (+7) 


``````````diff
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 52823430919de4..7df5141499552c 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1796,6 +1796,9 @@ def fprofile_generate_cold_function_coverage : Flag<["-"], "fprofile-generate-co
 def fprofile_generate_cold_function_coverage_EQ : Joined<["-"], "fprofile-generate-cold-function-coverage=">,
     Group<f_Group>, Visibility<[ClangOption, CLOption]>, MetaVarName<"<directory>">,
     HelpText<"Generate instrumented code to collect coverage info for cold functions into <directory>/default.profraw (overridden by LLVM_PROFILE_FILE env var)">;
+def fprofile_generate_temporal_instrumentation : Flag<["-"], "fprofile-generate-temporal-instrumentation">,
+    Group<f_Group>, Visibility<[ClangOption, CLOption]>,
+    HelpText<"Generate instrumented code to collect temporal information. See this RFC for details: https://discourse.llvm.org/t/rfc-temporal-profiling-extension-for-irpgo/68068">;
 def fprofile_instr_generate : Flag<["-"], "fprofile-instr-generate">,
     Group<f_Group>, Visibility<[ClangOption, CLOption]>,
     HelpText<"Generate instrumented code to collect execution counts into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var)">;
@@ -1891,7 +1894,7 @@ defm pseudo_probe_for_profiling : BoolFOption<"pseudo-probe-for-profiling",
           " pseudo probes for sample profiling">>;
 def forder_file_instrumentation : Flag<["-"], "forder-file-instrumentation">,
     Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>,
-    HelpText<"Generate instrumented code to collect order file into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var). Deprecated, please use temporal profiling.">;
+    HelpText<"Generate instrumented code to collect order file into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var). Deprecated, please use -fprofile-generate-temporal-instrumentation">;
 def fprofile_list_EQ : Joined<["-"], "fprofile-list=">,
     Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>,
     HelpText<"Filename defining the list of functions/files to instrument. "
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index a0002371da2f1b..a196bceba1f2d3 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -662,6 +662,15 @@ static void addPGOAndCoverageFlags(const ToolChain &TC, Compilation &C,
     CmdArgs.push_back("--pgo-function-entry-coverage");
   }
 
+  if (auto *A = Args.getLastArg(
+          options::OPT_fprofile_generate_temporal_instrumentation)) {
+    if (!PGOGenerateArg && !CSPGOGenerateArg)
+      D.Diag(clang::diag::err_drv_argument_only_allowed_with)
+          << A->getSpelling() << "-fprofile-generate or -fcs-profile-generate";
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("--pgo-temporal-instrumentation");
+  }
+
   Arg *PGOGenArg = nullptr;
   if (PGOGenerateArg) {
     assert(!CSPGOGenerateArg);
@@ -8050,7 +8059,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
           Args.getLastArg(options::OPT_forder_file_instrumentation)) {
     D.Diag(diag::warn_drv_deprecated_arg)
         << A->getAsString(Args) << /*hasReplacement=*/true
-        << "-mllvm -pgo-temporal-instrumentation";
+        << "-fprofile-generate-temporal-instrumentation";
     CmdArgs.push_back("-forder-file-instrumentation");
     // Enable order file instrumentation when ThinLTO is not on. When ThinLTO is
     // on, we need to pass these flags as linker flags and that will be handled
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index 2b72068eae1eeb..7448076cf367e5 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -424,7 +424,7 @@
 // CHECK-WARNING-DAG: optimization flag '-fno-devirtualize-speculatively' is not supported
 // CHECK-WARNING-DAG: the flag '-fslp-vectorize-aggressive' has been deprecated and will be ignored
 // CHECK-WARNING-DAG: the flag '-fno-slp-vectorize-aggressive' has been deprecated and will be ignored
-// CHECK-WARNING-DAG: argument '-forder-file-instrumentation' is deprecated, use '-mllvm -pgo-temporal-instrumentation' instead
+// CHECK-WARNING-DAG: argument '-forder-file-instrumentation' is deprecated, use '-fprofile-generate-temporal-instrumentation' instead
 
 // Test that we mute the warning on these
 // RUN: %clang -### -finline-limit=1000 -Wno-invalid-command-line-argument              \
diff --git a/clang/test/Driver/fprofile-generate-temporal-instrumentation.c b/clang/test/Driver/fprofile-generate-temporal-instrumentation.c
new file mode 100644
index 00000000000000..e4e5b5f49bcacf
--- /dev/null
+++ b/clang/test/Driver/fprofile-generate-temporal-instrumentation.c
@@ -0,0 +1,7 @@
+// RUN: %clang -### -c -fprofile-generate -fprofile-generate-temporal-instrumentation %s 2>&1 | FileCheck %s
+// RUN: %clang -### -c -fcs-profile-generate -fprofile-generate-temporal-instrumentation %s 2>&1 | FileCheck %s
+// RUN: not %clang -### -c -fprofile-generate-temporal-instrumentation %s 2>&1 | FileCheck %s --check-prefix=ERR
+
+// CHECK: "-mllvm" "--pgo-temporal-instrumentation"
+
+// ERR: '-fprofile-generate-temporal-instrumentation' only allowed with '-fprofile-generate or -fcs-profile-generate'

``````````

</details>


https://github.com/llvm/llvm-project/pull/122385