C++11 constexpr: Add note stacks containing backtraces if constant evaluation

fails within a call to a constexpr function. Add -fconstexpr-backtrace-limit
argument to driver and frontend, to control the maximum number of notes so
produced (default 10). Fix APValue printing to be able to pretty-print all
APValue types, and move the testing for this functionality from a unittest to
a -verify test now that it's visible in clang's output.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146749 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 1 deletions

diff --git a/include/clang/Frontend/DiagnosticOptions.h b/include/clang/Frontend/DiagnosticOptions.h
index 8433da4fa4..282ca5d366 100644
--- a/include/clang/Frontend/DiagnosticOptions.h
+++ b/include/clang/Frontend/DiagnosticOptions.h
@@ -51,12 +51,14 @@ public:
   unsigned ErrorLimit;           /// Limit # errors emitted.
   unsigned MacroBacktraceLimit;  /// Limit depth of macro expansion backtrace.
   unsigned TemplateBacktraceLimit; /// Limit depth of instantiation backtrace.
+  unsigned ConstexprBacktraceLimit; /// Limit depth of constexpr backtrace.
 
   /// The distance between tab stops.
   unsigned TabStop;
   enum { DefaultTabStop = 8, MaxTabStop = 100, 
          DefaultMacroBacktraceLimit = 6,
-         DefaultTemplateBacktraceLimit = 10 };
+         DefaultTemplateBacktraceLimit = 10,
+         DefaultConstexprBacktraceLimit = 10 };
 
   /// Column limit for formatting message diagnostics, or 0 if unused.
   unsigned MessageLength;
@@ -99,6 +101,7 @@ public:
     ErrorLimit = 0;
     TemplateBacktraceLimit = DefaultTemplateBacktraceLimit;
     MacroBacktraceLimit = DefaultMacroBacktraceLimit;
+    ConstexprBacktraceLimit = DefaultConstexprBacktraceLimit;
   }
 };