Add -pass-remarks flag to 'opt'.

Summary:
This adds support in 'opt' to filter pass remarks emitted by
optimization passes. A new flag -pass-remarks specifies which
passes should emit a diagnostic when LLVMContext::emitOptimizationRemark
is invoked.

This will allow the front end to simply pass along the regular
expression from its own -Rpass flag when launching the backend.

Depends on D3227.

Reviewers: qcolombet

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3291

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205775 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 61 insertions, 1 deletions

diff --git a/lib/IR/LLVMContext.cpp b/lib/IR/LLVMContext.cpp
index 3f05561a2c..0c922005b7 100644
--- a/lib/IR/LLVMContext.cpp
+++ b/lib/IR/LLVMContext.cpp
@@ -160,7 +160,8 @@ void LLVMContext::emitOptimizationRemark(const char *PassName,
                                          const Function &Fn,
                                          const DebugLoc &DLoc,
                                          const Twine &Msg) {
-  diagnose(DiagnosticInfoOptimizationRemark(PassName, Fn, DLoc, Msg));
+  if (pImpl->optimizationRemarksEnabledFor(PassName))
+    diagnose(DiagnosticInfoOptimizationRemark(PassName, Fn, DLoc, Msg));
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/IR/LLVMContextImpl.cpp b/lib/IR/LLVMContextImpl.cpp
index ebff9d3a51..d34f5b4841 100644
--- a/lib/IR/LLVMContextImpl.cpp
+++ b/lib/IR/LLVMContextImpl.cpp
@@ -15,6 +15,8 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Regex.h"
 #include <algorithm>
 using namespace llvm;
 
@@ -43,6 +45,59 @@ LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
 }
 
 namespace {
+
+/// \brief Regular expression corresponding to the value given in the
+/// command line flag -pass-remarks. Passes whose name matches this
+/// regexp will emit a diagnostic when calling
+/// LLVMContext::emitOptimizationRemark.
+static Regex *OptimizationRemarkPattern = 0;
+
+/// \brief String to hold all the values passed via -pass-remarks. Every
+/// instance of -pass-remarks on the command line will be concatenated
+/// to this string. Values are stored inside braces and concatenated with
+/// the '|' operator. This implements the expected semantics that multiple
+/// -pass-remarks are additive.
+static std::string OptimizationRemarkExpr;
+
+struct PassRemarksOpt {
+  void operator=(const std::string &Val) const {
+    // Create a regexp object to match pass names for emitOptimizationRemark.
+    if (!Val.empty()) {
+      if (!OptimizationRemarkExpr.empty())
+        OptimizationRemarkExpr += "|";
+      OptimizationRemarkExpr += "(" + Val + ")";
+      delete OptimizationRemarkPattern;
+      OptimizationRemarkPattern = new Regex(OptimizationRemarkExpr);
+      std::string RegexError;
+      if (!OptimizationRemarkPattern->isValid(RegexError))
+        report_fatal_error("Invalid regular expression '" + Val +
+                               "' in -pass-remarks: " + RegexError,
+                           false);
+    }
+  };
+};
+
+static PassRemarksOpt PassRemarksOptLoc;
+
+// -pass-remarks
+//    Command line flag to enable LLVMContext::emitOptimizationRemark()
+//    and LLVMContext::emitOptimizationNote() calls.
+static cl::opt<PassRemarksOpt, true, cl::parser<std::string>>
+PassRemarks("pass-remarks", cl::value_desc("pattern"),
+            cl::desc("Enable optimization remarks from passes whose name match "
+                     "the given regular expression"),
+            cl::Hidden, cl::location(PassRemarksOptLoc), cl::ValueRequired,
+            cl::ZeroOrMore);
+}
+
+bool
+LLVMContextImpl::optimizationRemarksEnabledFor(const char *PassName) const {
+  return OptimizationRemarkPattern &&
+         OptimizationRemarkPattern->match(PassName);
+}
+
+
+namespace {
 struct DropReferences {
   // Takes the value_type of a ConstantUniqueMap's internal map, whose 'second'
   // is a Constant*.
diff --git a/lib/IR/LLVMContextImpl.h b/lib/IR/LLVMContextImpl.h
index dc77d291f4..48b3511367 100644
--- a/lib/IR/LLVMContextImpl.h
+++ b/lib/IR/LLVMContextImpl.h
@@ -368,6 +368,10 @@ public:
   typedef DenseMap<const Function *, ReturnInst *> PrefixDataMapTy;
   PrefixDataMapTy PrefixDataMap;
 
+  /// \brief Return true if the given pass name should emit optimization
+  /// remarks.
+  bool optimizationRemarksEnabledFor(const char *PassName) const;
+
   int getOrAddScopeRecordIdxEntry(MDNode *N, int ExistingIdx);
   int getOrAddScopeInlinedAtIdxEntry(MDNode *Scope, MDNode *IA,int ExistingIdx);