[clang][cli] NFC: Ensure non-null DiagnosticsEngine in ParseDiagnosticArgs

Before this patch, ParseDiagnosticArgs can be called with a nullptr DiagnosticsEngine *. This happens early on in the compilation process, where no proper DiagnosticEngine exists, because the diagnostic options (passed through command line) are not known yet.

This patch ensures nullptr is replaced by an ignoring DiagnosticEngine in ParseDiagnosticArgs, which allows to switch from pointer to a reference in some utility functions.

Besides simplifying the code, this patch enables a future patch (D84673) that ports diagnostic options to the new marshalling infrastructure.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D93701

1 files changed, 25 insertions, 25 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 7fb7ec8..7f3e39e 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -830,7 +830,7 @@ GenerateOptimizationRemarkRegex(DiagnosticsEngine &Diags, ArgList &Args,
 
 static bool parseDiagnosticLevelMask(StringRef FlagName,
                                      const std::vector<std::string> &Levels,
-                                     DiagnosticsEngine *Diags,
+                                     DiagnosticsEngine &Diags,
                                      DiagnosticLevelMask &M) {
   bool Success = true;
   for (const auto &Level : Levels) {
@@ -843,8 +843,7 @@ static bool parseDiagnosticLevelMask(StringRef FlagName,
         .Default(DiagnosticLevelMask::None);
     if (PM == DiagnosticLevelMask::None) {
       Success = false;
-      if (Diags)
-        Diags->Report(diag::err_drv_invalid_value) << FlagName << Level;
+      Diags.Report(diag::err_drv_invalid_value) << FlagName << Level;
     }
     M = M | PM;
   }
@@ -1383,7 +1382,7 @@ static bool parseShowColorsArgs(const ArgList &Args, bool DefaultColor) {
 }
 
 static bool checkVerifyPrefixes(const std::vector<std::string> &VerifyPrefixes,
-                                DiagnosticsEngine *Diags) {
+                                DiagnosticsEngine &Diags) {
   bool Success = true;
   for (const auto &Prefix : VerifyPrefixes) {
     // Every prefix must start with a letter and contain only alphanumeric
@@ -1393,10 +1392,8 @@ static bool checkVerifyPrefixes(const std::vector<std::string> &VerifyPrefixes,
     });
     if (BadChar != Prefix.end() || !isLetter(Prefix[0])) {
       Success = false;
-      if (Diags) {
-        Diags->Report(diag::err_drv_invalid_value) << "-verify=" << Prefix;
-        Diags->Report(diag::note_drv_verify_prefix_spelling);
-      }
+      Diags.Report(diag::err_drv_invalid_value) << "-verify=" << Prefix;
+      Diags.Report(diag::note_drv_verify_prefix_spelling);
     }
   }
   return Success;
@@ -1405,6 +1402,13 @@ static bool checkVerifyPrefixes(const std::vector<std::string> &VerifyPrefixes,
 bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
                                 DiagnosticsEngine *Diags,
                                 bool DefaultDiagColor) {
+  Optional<DiagnosticsEngine> IgnoringDiags;
+  if (!Diags) {
+    IgnoringDiags.emplace(new DiagnosticIDs(), new DiagnosticOptions(),
+                          new IgnoringDiagConsumer());
+    Diags = &*IgnoringDiags;
+  }
+
   bool Success = true;
 
   Opts.DiagnosticLogFile =
@@ -1439,10 +1443,9 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     Opts.setShowOverloads(Ovl_All);
   else {
     Success = false;
-    if (Diags)
-      Diags->Report(diag::err_drv_invalid_value)
-      << Args.getLastArg(OPT_fshow_overloads_EQ)->getAsString(Args)
-      << ShowOverloads;
+    Diags->Report(diag::err_drv_invalid_value)
+        << Args.getLastArg(OPT_fshow_overloads_EQ)->getAsString(Args)
+        << ShowOverloads;
   }
 
   StringRef ShowCategory =
@@ -1455,10 +1458,9 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     Opts.ShowCategories = 2;
   else {
     Success = false;
-    if (Diags)
-      Diags->Report(diag::err_drv_invalid_value)
-      << Args.getLastArg(OPT_fdiagnostics_show_category)->getAsString(Args)
-      << ShowCategory;
+    Diags->Report(diag::err_drv_invalid_value)
+        << Args.getLastArg(OPT_fdiagnostics_show_category)->getAsString(Args)
+        << ShowCategory;
   }
 
   StringRef Format =
@@ -1474,10 +1476,9 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     Opts.setFormat(DiagnosticOptions::Vi);
   else {
     Success = false;
-    if (Diags)
-      Diags->Report(diag::err_drv_invalid_value)
-      << Args.getLastArg(OPT_fdiagnostics_format)->getAsString(Args)
-      << Format;
+    Diags->Report(diag::err_drv_invalid_value)
+        << Args.getLastArg(OPT_fdiagnostics_format)->getAsString(Args)
+        << Format;
   }
 
   Opts.ShowSourceRanges = Args.hasArg(OPT_fdiagnostics_print_source_range_info);
@@ -1488,7 +1489,7 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     Opts.VerifyPrefixes.push_back("expected");
   // Keep VerifyPrefixes in its original order for the sake of diagnostics, and
   // then sort it to prepare for fast lookup using std::binary_search.
-  if (!checkVerifyPrefixes(Opts.VerifyPrefixes, Diags)) {
+  if (!checkVerifyPrefixes(Opts.VerifyPrefixes, *Diags)) {
     Opts.VerifyDiagnostics = false;
     Success = false;
   }
@@ -1497,7 +1498,7 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
   DiagnosticLevelMask DiagMask = DiagnosticLevelMask::None;
   Success &= parseDiagnosticLevelMask("-verify-ignore-unexpected=",
     Args.getAllArgValues(OPT_verify_ignore_unexpected_EQ),
-    Diags, DiagMask);
+    *Diags, DiagMask);
   if (Args.hasArg(OPT_verify_ignore_unexpected))
     DiagMask = DiagnosticLevelMask::All;
   Opts.setVerifyIgnoreUnexpected(DiagMask);
@@ -1523,9 +1524,8 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
                                     DiagnosticOptions::DefaultTabStop, Diags);
   if (Opts.TabStop == 0 || Opts.TabStop > DiagnosticOptions::MaxTabStop) {
     Opts.TabStop = DiagnosticOptions::DefaultTabStop;
-    if (Diags)
-      Diags->Report(diag::warn_ignoring_ftabstop_value)
-      << Opts.TabStop << DiagnosticOptions::DefaultTabStop;
+    Diags->Report(diag::warn_ignoring_ftabstop_value)
+        << Opts.TabStop << DiagnosticOptions::DefaultTabStop;
   }
   Opts.MessageLength =
       getLastArgIntValue(Args, OPT_fmessage_length_EQ, 0, Diags);