Un-revert "[Driver] Add -fdiagnostics-hotness-threshold"

Summary:
Un-revert https://reviews.llvm.org/D34868, but with a slight tweak to the
documentation to fix an error -- I had used the wrong syntax for a link.

llvm-svn: 306948

clang/docs/UsersManual.rst

@@ -322,18 +322,27 @@ output format of the diagnostics that it generates.
    by category, so it should be a high level category. We want dozens
    of these, not hundreds or thousands of them.
 
+.. _opt_fsave-optimization-record:
+
+**-fsave-optimization-record**
+   Write optimization remarks to a YAML file.
+
+   This option, which defaults to off, controls whether Clang writes
+   optimization reports to a YAML file. By recording diagnostics in a file,
+   using a structured YAML format, users can parse or sort the remarks in a
+   convenient way.
+
 .. _opt_fdiagnostics-show-hotness:
 
 **-f[no-]diagnostics-show-hotness**
    Enable profile hotness information in diagnostic line.
 
-   This option, which defaults to off, controls whether Clang prints the
-   profile hotness associated with a diagnostics in the presence of
-   profile-guided optimization information.  This is currently supported with
-   optimization remarks (see :ref:`Options to Emit Optimization Reports
-   <rpass>`).  The hotness information allows users to focus on the hot
-   optimization remarks that are likely to be more relevant for run-time
-   performance.
+   This option controls whether Clang prints the profile hotness associated
+   with diagnostics in the presence of profile-guided optimization information.
+   This is currently supported with optimization remarks (see
+   :ref:`Options to Emit Optimization Reports <rpass>`). The hotness information
+   allows users to focus on the hot optimization remarks that are likely to be
+   more relevant for run-time performance.
 
    For example, in this output, the block containing the callsite of `foo` was
    executed 3000 times according to the profile data:
@@ -344,6 +353,23 @@ output format of the diagnostics that it generates.
            sum += foo(x, x - 2);
                   ^
 
+   This option is implied when
+   :ref:`-fsave-optimization-record <opt_fsave-optimization-record>` is used.
+   Otherwise, it defaults to off.
+
+.. _opt_fdiagnostics-hotness-threshold:
+
+**-fdiagnostics-hotness-threshold**
+   Prevent optimization remarks from being output if they do not have at least
+   this hotness value.
+
+   This option, which defaults to zero, controls the minimum hotness an
+   optimization remark would need in order to be output by Clang. This is
+   currently supported with optimization remarks (see :ref:`Options to Emit
+   Optimization Reports <rpass>`) when profile hotness information in
+   diagnostics is enabled (see
+   :ref:`-fdiagnostics-show-hotness <opt_fdiagnostics-show-hotness>`).
+
 .. _opt_fdiagnostics-fixit-info:
 
 **-f[no-]diagnostics-fixit-info**

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -198,8 +198,8 @@ def warn_drv_unused_argument : Warning<
 def warn_drv_empty_joined_argument : Warning<
   "joined argument expects additional value: '%0'">,
   InGroup<UnusedCommandLineArgument>;
-def warn_drv_fdiagnostics_show_hotness_requires_pgo : Warning<
-  "argument '-fdiagnostics-show-hotness' requires profile-guided optimization information">,
+def warn_drv_diagnostics_hotness_requires_pgo : Warning<
+  "argument '%0' requires profile-guided optimization information">,
   InGroup<UnusedCommandLineArgument>;
 def warn_drv_clang_unsupported : Warning<
   "the clang compiler does not support '%0'">;

clang/include/clang/Driver/Options.td

@@ -723,6 +723,9 @@ def fdiagnostics_print_source_range_info : Flag<["-"], "fdiagnostics-print-sourc
     HelpText<"Print source range spans in numeric form">;
 def fdiagnostics_show_hotness : Flag<["-"], "fdiagnostics-show-hotness">, Group<f_Group>,
     Flags<[CC1Option]>, HelpText<"Enable profile hotness information in diagnostic line">;
+def fdiagnostics_hotness_threshold_EQ : Joined<["-"], "fdiagnostics-hotness-threshold=">,
+    Group<f_Group>, Flags<[CC1Option]>, MetaVarName<"<number>">,
+    HelpText<"Prevent optimization remarks from being output if they do not have at least this profile count">;
 def fdiagnostics_show_option : Flag<["-"], "fdiagnostics-show-option">, Group<f_Group>,
     Flags<[CC1Option]>, HelpText<"Print option name with mappable diagnostics">;
 def fdiagnostics_show_note_include_stack : Flag<["-"], "fdiagnostics-show-note-include-stack">,

clang/include/clang/Frontend/CodeGenOptions.def

@@ -261,6 +261,10 @@ VALUE_CODEGENOPT(EmitCheckPathComponentsToStrip, 32, 0)
 /// Whether to report the hotness of the code region for optimization remarks.
 CODEGENOPT(DiagnosticsWithHotness, 1, 0)
 
+/// The minimum hotness value a diagnostic needs in order to be included in
+/// optimization diagnostics.
+VALUE_CODEGENOPT(DiagnosticsHotnessThreshold, 32, 0)
+
 /// Whether copy relocations support is available when building as PIE.
 CODEGENOPT(PIECopyRelocations, 1, 0)
 

clang/lib/CodeGen/CodeGenAction.cpp

@@ -229,6 +229,9 @@ namespace clang {
       void *OldDiagnosticContext = Ctx.getDiagnosticContext();
       Ctx.setDiagnosticHandler(DiagnosticHandler, this);
       Ctx.setDiagnosticsHotnessRequested(CodeGenOpts.DiagnosticsWithHotness);
+      if (CodeGenOpts.DiagnosticsHotnessThreshold != 0)
+        Ctx.setDiagnosticsHotnessThreshold(
+            CodeGenOpts.DiagnosticsHotnessThreshold);
 
       std::unique_ptr<llvm::tool_output_file> OptRecordFile;
       if (!CodeGenOpts.OptRecordFile.empty()) {

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4043,6 +4043,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    options::OPT_fno_diagnostics_show_hotness, false))
     CmdArgs.push_back("-fdiagnostics-show-hotness");
 
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_fdiagnostics_hotness_threshold_EQ)) {
+    std::string Opt = std::string("-fdiagnostics-hotness-threshold=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Opt));
+  }
+
   if (const Arg *A = Args.getLastArg(options::OPT_fdiagnostics_format_EQ)) {
     CmdArgs.push_back("-fdiagnostics-format");
     CmdArgs.push_back(A->getValue());

clang/lib/Frontend/CompilerInvocation.cpp

@@ -909,12 +909,18 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DiagnosticsWithHotness =
       Args.hasArg(options::OPT_fdiagnostics_show_hotness);
   bool UsingSampleProfile = !Opts.SampleProfileFile.empty();
+  bool UsingProfile = UsingSampleProfile ||
+      (Opts.getProfileUse() != CodeGenOptions::ProfileNone);
 
-  if (Opts.DiagnosticsWithHotness &&
-      Opts.getProfileUse() == CodeGenOptions::ProfileNone &&
-      !UsingSampleProfile) {
-    Diags.Report(diag::warn_drv_fdiagnostics_show_hotness_requires_pgo);
-  }
+  if (Opts.DiagnosticsWithHotness && !UsingProfile)
+    Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
+        << "-fdiagnostics-show-hotness";
+
+  Opts.DiagnosticsHotnessThreshold = getLastArgUInt64Value(
+      Args, options::OPT_fdiagnostics_hotness_threshold_EQ, 0);
+  if (Opts.DiagnosticsHotnessThreshold > 0 && !UsingProfile)
+    Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
+        << "-fdiagnostics-hotness-threshold=";
 
   // If the user requested to use a sample profile for PGO, then the
   // backend will need to track source location information so the profile

clang/test/Frontend/Inputs/optimization-remark-with-hotness-sample.proftext

@@ -1,7 +1,7 @@
 foo:0:0
  0: 0
 bar:29:29
- 6: foo:0
+ 9: foo:0
 main:0:0
  0: 0 bar:0
 

clang/test/Frontend/optimization-remark-with-hotness.c

@@ -15,12 +15,14 @@
 // RUN:     optimization-remark-with-hotness.c %s -emit-llvm-only \
 // RUN:     -fprofile-sample-use=%t-sample.profdata -Rpass=inline \
 // RUN:     -Rpass-analysis=inline -Rpass-missed=inline \
-// RUN:     -fdiagnostics-show-hotness -verify
+// RUN:     -fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=10 \
+// RUN:     -verify
 // The clang version of the previous test.
 // RUN: %clang -target x86_64-apple-macosx10.9 %s -c -emit-llvm -o /dev/null \
 // RUN:     -fprofile-instr-use=%t.profdata -Rpass=inline \
 // RUN:     -Rpass-analysis=inline -Rpass-missed=inline \
-// RUN:     -fdiagnostics-show-hotness -Xclang -verify
+// RUN:     -fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=10 \
+// RUN:     -Xclang -verify
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name \
 // RUN:     optimization-remark-with-hotness.c %s -emit-llvm-only \
 // RUN:     -fprofile-instrument-use-path=%t.profdata -Rpass=inline \
@@ -28,11 +30,18 @@
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name \
 // RUN:     optimization-remark-with-hotness.c %s -emit-llvm-only \
 // RUN:     -fprofile-instrument-use-path=%t.profdata -Rpass=inline \
-// RUN:     -Rpass-analysis=inline -Rno-pass-with-hotness  2>&1 | FileCheck \
+// RUN:     -Rpass-analysis=inline -Rno-pass-with-hotness 2>&1 | FileCheck \
 // RUN:     -check-prefix=HOTNESS_OFF %s
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name \
 // RUN:     optimization-remark-with-hotness.c %s -emit-llvm-only \
-// RUN:     -Rpass=inline -Rpass-analysis=inline -fdiagnostics-show-hotness  2>&1 \
+// RUN:     -fprofile-instrument-use-path=%t.profdata -Rpass=inline \
+// RUN:     -Rpass-analysis=inline -fdiagnostics-show-hotness \
+// RUN:     -fdiagnostics-hotness-threshold=100 2>&1 \
+// RUN:     | FileCheck -allow-empty -check-prefix=THRESHOLD %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name \
+// RUN:     optimization-remark-with-hotness.c %s -emit-llvm-only \
+// RUN:     -Rpass=inline -Rpass-analysis=inline \
+// RUN:     -fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=10 2>&1 \
 // RUN:     | FileCheck -check-prefix=NO_PGO %s
 
 int foo(int x, int y) __attribute__((always_inline));
@@ -43,7 +52,10 @@ int sum = 0;
 void bar(int x) {
   // HOTNESS_OFF: foo inlined into bar
   // HOTNESS_OFF-NOT: hotness:
+  // THRESHOLD-NOT: inlined
+  // THRESHOLD-NOT: hotness
   // NO_PGO: '-fdiagnostics-show-hotness' requires profile-guided optimization information
+  // NO_PGO: '-fdiagnostics-hotness-threshold=' requires profile-guided optimization information
   // expected-remark@+2 {{foo should always be inlined (cost=always) (hotness: 30)}}
   // expected-remark@+1 {{foo inlined into bar (hotness: 30)}}
   sum += foo(x, x - 2);