[Flang][Driver] Implement OPT_R_Joined options

Add a BackendRemarkConsumer class, responsible for handling diagnostics
received from LLVM. The diagnostics being information on middle and
backend passes used or not used.

Clang by default has all remarks ignored but manually sets the severity of
`R_Group` to visible(`clang::diag::clang::Severity::Remark`). This patch does
the same for Flang.

Depends on D157410. That patch adds the R family of options to
`FlangOption` and `FC1Option` in
`clang/include/clang/Driver/Options.td`

Reviewed By: awarzynski

Differential Revision: https://reviews.llvm.org/D158174

1 files changed, 54 insertions, 0 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index ecafa4e..f2a7ffd 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -153,6 +153,38 @@ static bool parseDebugArgs(Fortran::frontend::CodeGenOptions &opts,
   return true;
 }
 
+// Generate an OptRemark object containing info on if the -Rgroup
+// specified is enabled or not.
+static CodeGenOptions::OptRemark
+parseOptimizationRemark(llvm::opt::ArgList &args,
+                        llvm::StringRef remarkOptName) {
+  assert((remarkOptName == "pass" || remarkOptName == "pass-missed" ||
+          remarkOptName == "pass-analysis") &&
+         "Unknown group name provided.");
+  CodeGenOptions::OptRemark result;
+
+  for (llvm::opt::Arg *a : args) {
+    if (a->getOption().matches(clang::driver::options::OPT_R_Joined)) {
+      llvm::StringRef value = a->getValue();
+
+      if (value == remarkOptName) {
+        result.Kind = CodeGenOptions::RemarkKind::RK_Enabled;
+        // Enable everything
+        result.Pattern = ".*";
+        result.Regex = std::make_shared<llvm::Regex>(result.Pattern);
+
+      } else if (value.split('-') ==
+                 std::make_pair(llvm::StringRef("no"), remarkOptName)) {
+        result.Kind = CodeGenOptions::RemarkKind::RK_Disabled;
+        // Disable everything
+        result.Pattern = "";
+        result.Regex = nullptr;
+      }
+    }
+  }
+  return result;
+}
+
 static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
                              llvm::opt::ArgList &args,
                              clang::DiagnosticsEngine &diags) {
@@ -194,14 +226,30 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
           args.getLastArg(clang::driver::options::OPT_opt_record_file))
     opts.OptRecordFile = a->getValue();
 
+  // Optimization file format. Defaults to yaml
   if (const llvm::opt::Arg *a =
           args.getLastArg(clang::driver::options::OPT_opt_record_format))
     opts.OptRecordFormat = a->getValue();
 
+  // Specifies, using a regex, which successful optimization passes(middle and
+  // backend), to include in the final optimization record file generated. If
+  // not provided -fsave-optimization-record will include all passes.
   if (const llvm::opt::Arg *a =
           args.getLastArg(clang::driver::options::OPT_opt_record_passes))
     opts.OptRecordPasses = a->getValue();
 
+  // Create OptRemark that allows printing of all successful optimization
+  // passes applied.
+  opts.OptimizationRemark = parseOptimizationRemark(args, "pass");
+
+  // Create OptRemark that allows all missed optimization passes to be printed.
+  opts.OptimizationRemarkMissed = parseOptimizationRemark(args, "pass-missed");
+
+  // Create OptRemark that allows all optimization decisions made by LLVM
+  // to be printed.
+  opts.OptimizationRemarkAnalysis =
+      parseOptimizationRemark(args, "pass-analysis");
+
   if (auto *a = args.getLastArg(clang::driver::options::OPT_save_temps_EQ))
     opts.SaveTempsDir = a->getValue();
 
@@ -959,6 +1007,12 @@ bool CompilerInvocation::createFromArgs(
     res.loweringOpts.setNoPPCNativeVecElemOrder(true);
   }
 
+  // Preserve all the remark options requested, i.e. -Rpass, -Rpass-missed or
+  // -Rpass-analysis. This will be used later when processing and outputting the
+  // remarks generated by LLVM in ExecuteCompilerInvocation.cpp.
+  for (auto *a : args.filtered(clang::driver::options::OPT_R_Group))
+    res.getDiagnosticOpts().Remarks.push_back(a->getValue());
+
   success &= parseFrontendArgs(res.getFrontendOpts(), args, diags);
   parseTargetArgs(res.getTargetOpts(), args);
   parsePreprocessorArgs(res.getPreprocessorOpts(), args);