5 files changed, 38 insertions, 2 deletions
diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp
index 755fbed66f3..1870195ded0 100644
--- a/clang/lib/Basic/Diagnostic.cpp
+++ b/clang/lib/Basic/Diagnostic.cpp
@@ -224,7 +224,8 @@ Diagnostic::Diagnostic(DiagnosticClient *client) : Client(client) {
   ErrorOccurred = false;
   FatalErrorOccurred = false;
   ErrorLimit = 0;
-  
+  TemplateBacktraceLimit = 0;
+
   NumWarnings = 0;
   NumErrors = 0;
   NumErrorsSuppressed = 0;
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d9df471714a..4653551a469 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1079,6 +1079,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(A->getValue(Args));
   else
     CmdArgs.push_back("19");
+
+  CmdArgs.push_back("-ftemplate-backtrace-limit");
+  if (Arg *A = Args.getLastArg(options::OPT_ftemplate_backtrace_limit_EQ))
+    CmdArgs.push_back(A->getValue(Args));
+  else
+    CmdArgs.push_back("10");
   
   // Pass -fmessage-length=.
   CmdArgs.push_back("-fmessage-length");
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 932481f87f6..f9cfd73c7e6 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -240,6 +240,11 @@ static void DiagnosticOptsToArgs(const DiagnosticOptions &Opts,
     Res.push_back("-ferror-limit");
     Res.push_back(llvm::utostr(Opts.ErrorLimit));
   }
+  if (Opts.TemplateBacktraceLimit != 10) {
+    Res.push_back("-ftemplate-backtrace-limit");
+    Res.push_back(llvm::utostr(Opts.TemplateBacktraceLimit));
+  }
+
   if (Opts.TabStop != DiagnosticOptions::DefaultTabStop) {
     Res.push_back("-ftabstop");
     Res.push_back(llvm::utostr(Opts.TabStop));
@@ -857,6 +862,8 @@ static void ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
   Opts.VerifyDiagnostics = Args.hasArg(OPT_verify);
   Opts.BinaryOutput = Args.hasArg(OPT_fdiagnostics_binary);
   Opts.ErrorLimit = getLastArgIntValue(Args, OPT_ferror_limit, 0, Diags);
+  Opts.TemplateBacktraceLimit
+    = getLastArgIntValue(Args, OPT_ftemplate_backtrace_limit, 0, Diags);
   Opts.TabStop = getLastArgIntValue(Args, OPT_ftabstop,
                                     DiagnosticOptions::DefaultTabStop, Diags);
   if (Opts.TabStop == 0 || Opts.TabStop > DiagnosticOptions::MaxTabStop) {
diff --git a/clang/lib/Frontend/Warnings.cpp b/clang/lib/Frontend/Warnings.cpp
index 39cda8783b4..84c4f5d40fa 100644
--- a/clang/lib/Frontend/Warnings.cpp
+++ b/clang/lib/Frontend/Warnings.cpp
@@ -39,6 +39,8 @@ void clang::ProcessWarningOptions(Diagnostic &Diags,
   // Handle -ferror-limit
   if (Opts.ErrorLimit)
     Diags.setErrorLimit(Opts.ErrorLimit);
+  if (Opts.TemplateBacktraceLimit)
+    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
 
   // If -pedantic or -pedantic-errors was specified, then we want to map all
   // extension diagnostics onto WARNING or ERROR unless the user has futz'd
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index e35d988dc81..abc8e5fb560 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -339,12 +339,32 @@ bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
 /// \brief Prints the current instantiation stack through a series of
 /// notes.
 void Sema::PrintInstantiationStack() {
+  // Determine which template instantiations to skip, if any.
+  unsigned SkipStart = ActiveTemplateInstantiations.size(), SkipEnd = SkipStart;
+  unsigned Limit = Diags.getTemplateBacktraceLimit();
+  if (Limit && Limit < ActiveTemplateInstantiations.size()) {
+    SkipStart = Limit / 2 + Limit % 2;
+    SkipEnd = ActiveTemplateInstantiations.size() - Limit / 2;
+  }
+
   // FIXME: In all of these cases, we need to show the template arguments
+  unsigned InstantiationIdx = 0;
   for (llvm::SmallVector<ActiveTemplateInstantiation, 16>::reverse_iterator
          Active = ActiveTemplateInstantiations.rbegin(),
          ActiveEnd = ActiveTemplateInstantiations.rend();
        Active != ActiveEnd;
-       ++Active) {
+       ++Active, ++InstantiationIdx) {
+    // Skip this instantiation?
+    if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) {
+      if (InstantiationIdx == SkipStart) {
+        // Note that we're skipping instantiations.
+        Diags.Report(FullSourceLoc(Active->PointOfInstantiation, SourceMgr),
+                     diag::note_instantiation_contexts_suppressed)
+          << unsigned(ActiveTemplateInstantiations.size() - Limit);
+      }
+      continue;
+    }
+
     switch (Active->Kind) {
     case ActiveTemplateInstantiation::TemplateInstantiation: {
       Decl *D = reinterpret_cast<Decl *>(Active->Entity);