Add support for optimization reports.

Summary:
This patch adds a new flag -Rpass=. The flag indicates the name
of the optimization pass that should emit remarks stating when it
made a transformation to the code.

This implements the design I proposed in:

https://docs.google.com/document/d/1FYUatSjZZO-zmFBxjOiuOzAy9mhHA8hqdvklZv68WuQ/edit?usp=sharing

Other changes:
- Add DiagnosticIDs::isRemark(). Use it in printDiagnosticOptions to
  print "-R" instead of "-W" in the diagnostic message.

- In BackendConsumer::OptimizationRemarkHandler, get a SourceLocation
  object out of the file name, line and column number. Use that location
  in the call to Diags.Report().

- When -Rpass is used without debug info a note is emitted alerting
  the user that they need to use -gline-tables-only -gcolumn-info to
  get this information.

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3226

llvm-svn: 206401

5 files changed, 70 insertions, 1 deletions

diff --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp
index cf6933aeb1c..5334ae88d1c 100644
--- a/clang/lib/Basic/DiagnosticIDs.cpp
+++ b/clang/lib/Basic/DiagnosticIDs.cpp
@@ -361,6 +361,11 @@ bool DiagnosticIDs::isDefaultMappingAsError(unsigned DiagID) {
   return GetDefaultDiagMappingInfo(DiagID).getMapping() == diag::MAP_ERROR;
 }
 
+bool DiagnosticIDs::isRemark(unsigned DiagID) {
+  return DiagID < diag::DIAG_UPPER_LIMIT &&
+         getBuiltinDiagClass(DiagID) == CLASS_REMARK;
+}
+
 /// getDescription - Given a diagnostic ID, return a description of the
 /// issue.
 StringRef DiagnosticIDs::getDescription(unsigned DiagID) const {
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index 573f8e98e77..67859bad2b4 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -20,6 +20,7 @@
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/LLVMContext.h"
@@ -220,6 +221,11 @@ namespace clang {
     /// \return True if the diagnostic has been successfully reported, false
     /// otherwise.
     bool StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D);
+    /// \brief Specialized handler for the optimization diagnostic.
+    /// Note that this handler only accepts remarks and it always handles
+    /// them.
+    void
+    OptimizationRemarkHandler(const llvm::DiagnosticInfoOptimizationRemark &D);
   };
   
   void BackendConsumer::anchor() {}
@@ -374,6 +380,44 @@ BackendConsumer::StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D) {
   return true;
 }
 
+void BackendConsumer::OptimizationRemarkHandler(
+    const llvm::DiagnosticInfoOptimizationRemark &D) {
+  // We only support remarks.
+  assert (D.getSeverity() == llvm::DS_Remark);
+
+  // Optimization remarks are active only if -Rpass=regexp is given and the
+  // regular expression pattern in 'regexp' matches the name of the pass
+  // name in \p D.
+  if (CodeGenOpts.OptimizationRemarkPattern &&
+      CodeGenOpts.OptimizationRemarkPattern->match(D.getPassName())) {
+    SourceManager &SourceMgr = Context->getSourceManager();
+    FileManager &FileMgr = SourceMgr.getFileManager();
+    StringRef Filename;
+    unsigned Line, Column;
+    D.getLocation(&Filename, &Line, &Column);
+    SourceLocation Loc;
+    if (Line > 0) {
+      // If -gcolumn-info was not used, Column will be 0. This upsets the
+      // source manager, so if Column is not set, set it to 1.
+      if (Column == 0)
+        Column = 1;
+      Loc = SourceMgr.translateFileLineCol(FileMgr.getFile(Filename), Line,
+                                           Column);
+    }
+    Diags.Report(Loc, diag::remark_fe_backend_optimization_remark)
+        << D.getMsg().str();
+
+    if (Line == 0)
+      // If we could not extract a source location for the diagnostic,
+      // inform the user how they can get source locations back.
+      //
+      // FIXME: We should really be generating !srcloc annotations when
+      // -Rpass is used. !srcloc annotations need to be emitted in
+      // approximately the same spots as !dbg nodes.
+      Diags.Report(diag::note_fe_backend_optimization_remark_missing_loc);
+  }
+}
+
 /// \brief This function is invoked when the backend needs
 /// to report something to the user.
 void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
@@ -391,6 +435,11 @@ void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
       return;
     ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
     break;
+  case llvm::DK_OptimizationRemark:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<DiagnosticInfoOptimizationRemark>(DI));
+    return;
   default:
     // Plugin IDs are not bound to any value as they are set dynamically.
     ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 018f9ba5748..9f64c3fa461 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3417,6 +3417,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       A->render(Args, CmdArgs);
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_Rpass_EQ))
+    A->render(Args, CmdArgs);
+
   if (Args.hasArg(options::OPT_mkernel)) {
     if (!Args.hasArg(options::OPT_fapple_kext) && types::isCXX(InputType))
       CmdArgs.push_back("-fapple-kext");
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 6177a96fa7b..e51d2cf8529 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -520,6 +520,17 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.DependentLibraries = Args.getAllArgValues(OPT_dependent_lib);
 
+  if (Arg *A = Args.getLastArg(OPT_Rpass_EQ)) {
+    StringRef Val = A->getValue();
+    std::string RegexError;
+    Opts.OptimizationRemarkPattern = std::make_shared<llvm::Regex>(Val);
+    if (!Opts.OptimizationRemarkPattern->isValid(RegexError)) {
+      Diags.Report(diag::err_drv_optimization_remark_pattern)
+          << RegexError << A->getAsString(Args);
+      Opts.OptimizationRemarkPattern.reset();
+    }
+  }
+
   return Success;
 }
 
diff --git a/clang/lib/Frontend/TextDiagnosticPrinter.cpp b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
index 994a8f74ed4..3b5eca6dd9d 100644
--- a/clang/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -81,7 +81,8 @@ static void printDiagnosticOptions(raw_ostream &OS,
 
     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
     if (!Opt.empty()) {
-      OS << (Started ? "," : " [") << "-W" << Opt;
+      OS << (Started ? "," : " [")
+         << (DiagnosticIDs::isRemark(Info.getID()) ? "-R" : "-W") << Opt;
       Started = true;
     }
   }