Separate the notion of 'context' when recursing down in the parser and actual errors.

Summary:
Change how error messages are constructed and stored in Diagnostics.
Separate the notion of 'context' when recursing down in the parser and actual errors.
This will simplify adding some new features, like argument overloading and error recovery.

Reviewers: klimek

CC: cfe-commits, revane

Differential Revision: http://llvm-reviews.chandlerc.com/D1168

llvm-svn: 186602

1 files changed, 71 insertions, 22 deletions

diff --git a/clang/lib/ASTMatchers/Dynamic/Diagnostics.cpp b/clang/lib/ASTMatchers/Dynamic/Diagnostics.cpp
index 1ca1f365398..71aeb9a7540 100644
--- a/clang/lib/ASTMatchers/Dynamic/Diagnostics.cpp
+++ b/clang/lib/ASTMatchers/Dynamic/Diagnostics.cpp
@@ -13,20 +13,56 @@ namespace clang {
 namespace ast_matchers {
 namespace dynamic {
 
-Diagnostics::ArgStream &
-Diagnostics::ArgStream::operator<<(const Twine &Arg) {
+Diagnostics::ArgStream Diagnostics::pushContextFrame(ContextType Type,
+                                                     SourceRange Range) {
+  ContextStack.push_back(ContextFrame());
+  ContextFrame& data = ContextStack.back();
+  data.Type = Type;
+  data.Range = Range;
+  return ArgStream(&data.Args);
+}
+
+Diagnostics::Context::Context(ConstructMatcherEnum, Diagnostics *Error,
+                              StringRef MatcherName,
+                              const SourceRange &MatcherRange)
+    : Error(Error) {
+  Error->pushContextFrame(CT_MatcherConstruct, MatcherRange) << MatcherName;
+}
+
+Diagnostics::Context::Context(MatcherArgEnum, Diagnostics *Error,
+                              StringRef MatcherName,
+                              const SourceRange &MatcherRange,
+                              unsigned ArgNumber)
+    : Error(Error) {
+  Error->pushContextFrame(CT_MatcherArg, MatcherRange) << ArgNumber
+                                                       << MatcherName;
+}
+
+Diagnostics::Context::~Context() { Error->ContextStack.pop_back(); }
+
+Diagnostics::ArgStream &Diagnostics::ArgStream::operator<<(const Twine &Arg) {
   Out->push_back(Arg.str());
   return *this;
 }
 
-Diagnostics::ArgStream Diagnostics::pushErrorFrame(const SourceRange &Range,
-                                                   ErrorType Error) {
-  Frames.insert(Frames.begin(), ErrorFrame());
-  ErrorFrame &Last = Frames.front();
+Diagnostics::ArgStream Diagnostics::addError(const SourceRange &Range,
+                                             ErrorType Error) {
+  Errors.push_back(ErrorContent());
+  ErrorContent &Last = Errors.back();
+  Last.ContextStack = ContextStack;
   Last.Range = Range;
   Last.Type = Error;
-  ArgStream Out = { &Last.Args };
-  return Out;
+  return ArgStream(&Last.Args);
+}
+
+StringRef ContextTypeToString(Diagnostics::ContextType Type) {
+  switch (Type) {
+    case Diagnostics::CT_MatcherConstruct:
+      return "Error building matcher $0.";
+    case Diagnostics::CT_MatcherArg:
+      return "Error parsing argument $0 for matcher $1.";
+  }
+  llvm_unreachable("Unknown ContextType value.");
 }
 
 StringRef ErrorTypeToString(Diagnostics::ErrorType Type) {
@@ -42,10 +78,6 @@ StringRef ErrorTypeToString(Diagnostics::ErrorType Type) {
 
   case Diagnostics::ET_ParserStringError:
     return "Error parsing string token: <$0>";
-  case Diagnostics::ET_ParserMatcherArgFailure:
-    return "Error parsing argument $0 for matcher $1.";
-  case Diagnostics::ET_ParserMatcherFailure:
-    return "Error building matcher $0.";
   case Diagnostics::ET_ParserNoOpenParen:
     return "Error parsing matcher. Found token <$0> while looking for '('.";
   case Diagnostics::ET_ParserNoCloseParen:
@@ -95,25 +127,42 @@ std::string FormatErrorString(StringRef FormatString,
   return Out;
 }
 
-std::string Diagnostics::ErrorFrame::ToString() const {
-  StringRef FormatString = ErrorTypeToString(Type);
-  std::string ErrorOut = FormatErrorString(FormatString, Args);
+static std::string MaybeAddLineAndColumn(Twine Input,
+                                         const SourceRange &Range) {
   if (Range.Start.Line > 0 && Range.Start.Column > 0)
     return (Twine(Range.Start.Line) + ":" + Twine(Range.Start.Column) + ": " +
-            ErrorOut).str();
-  return ErrorOut;
+            Input).str();
+  return Input.str();
+}
+
+std::string Diagnostics::ContextFrame::ToString() const {
+  return MaybeAddLineAndColumn(
+      FormatErrorString(ContextTypeToString(Type), Args), Range);
+}
+
+std::string Diagnostics::ErrorContent::ToString() const {
+  return MaybeAddLineAndColumn(FormatErrorString(ErrorTypeToString(Type), Args),
+                               Range);
 }
 
 std::string Diagnostics::ToString() const {
-  if (Frames.empty()) return "";
-  return Frames[Frames.size() - 1].ToString();
+  std::string Result;
+  for (size_t i = 0, e = Errors.size(); i != e; ++i) {
+    if (i != 0) Result += "\n";
+    Result += Errors[i].ToString();
+  }
+  return Result;
 }
 
 std::string Diagnostics::ToStringFull() const {
   std::string Result;
-  for (size_t i = 0, end = Frames.size(); i != end; ++i) {
-    if (i > 0) Result += "\n";
-    Result += Frames[i].ToString();
+  for (size_t i = 0, e = Errors.size(); i != e; ++i) {
+    if (i != 0) Result += "\n";
+    const ErrorContent &Error = Errors[i];
+    for (size_t i = 0, e = Error.ContextStack.size(); i != e; ++i) {
+      Result += Error.ContextStack[i].ToString() + "\n";
+    }
+    Result += Error.ToString();
   }
   return Result;
 }