r372203 - [lldb] Print better diagnostics for user expressions and modules

[Raphael Isemann via cfe-commits]

Author: teemperor
Date: Wed Sep 18 01:53:35 2019
New Revision: 372203

URL: http://llvm.org/viewvc/llvm-project?rev=372203&view=rev
Log:
[lldb] Print better diagnostics for user expressions and modules

Summary:
Currently our expression evaluators only prints very basic errors that are not very useful when writing complex expressions.

For example, in the expression below the user made a type error, but it's not clear from the diagnostic what went wrong:
```
(lldb) expr printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
error: invalid operands to binary expression ('int' and 'double')
```

This patch enables full Clang diagnostics in our expression evaluator. After this patch the diagnostics for the expression look like this:

```
(lldb) expr printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
error: <user expression 1>:1:54: invalid operands to binary expression ('int' and 'float')
printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
                                               ~~~~~~^~~~
```

To make this possible, we now emulate a user expression file within our diagnostics. This prevents that the user is exposed to
our internal wrapper code we inject.

Note that the diagnostics that refer to declarations from the debug information (e.g. 'note' diagnostics pointing to a called function)
will not be improved by this as they don't have any source locations associated with them, so caret or line printing isn't possible.
We instead just suppress these diagnostics as we already do with warnings as they would otherwise just be a context message
without any context (and the original diagnostic in the user expression should be enough to explain the issue).

Fixes rdar://24306342

Reviewers: JDevlieghere, aprantl, shafik, #lldb

Reviewed By: JDevlieghere, #lldb

Subscribers: usaxena95, davide, jingham, aprantl, arphaman, kadircet, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D65646

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticOptions.def
    cfe/trunk/lib/Frontend/TextDiagnostic.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticOptions.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticOptions.def?rev=372203&r1=372202&r2=372203&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticOptions.def (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticOptions.def Wed Sep 18 01:53:35 2019
@@ -49,6 +49,7 @@ DIAGOPT(Pedantic, 1, 0)         /// -ped
 DIAGOPT(PedanticErrors, 1, 0)   /// -pedantic-errors
 DIAGOPT(ShowColumn, 1, 1)       /// Show column number on diagnostics.
 DIAGOPT(ShowLocation, 1, 1)     /// Show source location information.
+DIAGOPT(ShowLevel, 1, 1)        /// Show diagnostic level.
 DIAGOPT(AbsolutePath, 1, 0)     /// Use absolute paths.
 DIAGOPT(ShowCarets, 1, 1)       /// Show carets in diagnostics.
 DIAGOPT(ShowFixits, 1, 1)       /// Show fixit information.

Modified: cfe/trunk/lib/Frontend/TextDiagnostic.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/TextDiagnostic.cpp?rev=372203&r1=372202&r2=372203&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/TextDiagnostic.cpp (original)
+++ cfe/trunk/lib/Frontend/TextDiagnostic.cpp Wed Sep 18 01:53:35 2019
@@ -683,8 +683,9 @@ void TextDiagnostic::emitDiagnosticMessa
   if (DiagOpts->ShowColors)
     OS.resetColor();
 
-  printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
-                       DiagOpts->CLFallbackMode);
+  if (DiagOpts->ShowLevel)
+    printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
+                         DiagOpts->CLFallbackMode);
   printDiagnosticMessage(OS,
                          /*IsSupplemental*/ Level == DiagnosticsEngine::Note,
                          Message, OS.tell() - StartOfLocationInfo,