[Driver] Actually report errors during parsing instead of stopping when there's an error somewhere.

This is a more principled version of r303756. That change was both very
brittle about the state of the Diags object going into the driver and
also broke tooling in funny ways.

In particular it prevented tools from capturing diagnostics properly and
made the compilation database logic fail to provide arguments to the
tool, falling back to scanning directories for JSON files.

llvm-svn: 306822

2 files changed, 32 insertions, 15 deletions

diff --git a/clang/lib/Driver/Compilation.cpp b/clang/lib/Driver/Compilation.cpp
index 5c13e59a0d7..cf86644fb8c 100644
--- a/clang/lib/Driver/Compilation.cpp
+++ b/clang/lib/Driver/Compilation.cpp
@@ -23,10 +23,11 @@ using namespace clang;
 using namespace llvm::opt;
 
 Compilation::Compilation(const Driver &D, const ToolChain &_DefaultToolChain,
-                         InputArgList *_Args, DerivedArgList *_TranslatedArgs)
+                         InputArgList *_Args, DerivedArgList *_TranslatedArgs,
+                         bool ContainsError)
     : TheDriver(D), DefaultToolChain(_DefaultToolChain), ActiveOffloadMask(0u),
       Args(_Args), TranslatedArgs(_TranslatedArgs), Redirects(nullptr),
-      ForDiagnostics(false) {
+      ForDiagnostics(false), ContainsError(ContainsError) {
   // The offloading host toolchain is the default tool chain.
   OrderedOffloadingToolchains.insert(
       std::make_pair(Action::OFK_Host, &DefaultToolChain));
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index f23975829ea..faced0697ed 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -153,8 +153,10 @@ void Driver::setDriverModeFromOption(StringRef Opt) {
     Diag(diag::err_drv_unsupported_option_argument) << OptName << Value;
 }
 
-InputArgList Driver::ParseArgStrings(ArrayRef<const char *> ArgStrings) {
+InputArgList Driver::ParseArgStrings(ArrayRef<const char *> ArgStrings,
+                                     bool &ContainsError) {
   llvm::PrettyStackTraceString CrashInfo("Command line argument parsing");
+  ContainsError = false;
 
   unsigned IncludedFlagsBitmask;
   unsigned ExcludedFlagsBitmask;
@@ -167,27 +169,41 @@ InputArgList Driver::ParseArgStrings(ArrayRef<const char *> ArgStrings) {
                           IncludedFlagsBitmask, ExcludedFlagsBitmask);
 
   // Check for missing argument error.
-  if (MissingArgCount)
-    Diag(clang::diag::err_drv_missing_argument)
+  if (MissingArgCount) {
+    Diag(diag::err_drv_missing_argument)
         << Args.getArgString(MissingArgIndex) << MissingArgCount;
+    ContainsError |=
+        Diags.getDiagnosticLevel(diag::err_drv_missing_argument,
+                                 SourceLocation()) > DiagnosticsEngine::Warning;
+  }
 
   // Check for unsupported options.
   for (const Arg *A : Args) {
     if (A->getOption().hasFlag(options::Unsupported)) {
-      Diag(clang::diag::err_drv_unsupported_opt) << A->getAsString(Args);
+      Diag(diag::err_drv_unsupported_opt) << A->getAsString(Args);
+      ContainsError |= Diags.getDiagnosticLevel(diag::err_drv_unsupported_opt,
+                                                SourceLocation()) >
+                       DiagnosticsEngine::Warning;
       continue;
     }
 
     // Warn about -mcpu= without an argument.
     if (A->getOption().matches(options::OPT_mcpu_EQ) && A->containsValue("")) {
-      Diag(clang::diag::warn_drv_empty_joined_argument) << A->getAsString(Args);
+      Diag(diag::warn_drv_empty_joined_argument) << A->getAsString(Args);
+      ContainsError |= Diags.getDiagnosticLevel(
+                           diag::warn_drv_empty_joined_argument,
+                           SourceLocation()) > DiagnosticsEngine::Warning;
     }
   }
 
-  for (const Arg *A : Args.filtered(options::OPT_UNKNOWN))
-    Diags.Report(IsCLMode() ? diag::warn_drv_unknown_argument_clang_cl :
-                              diag::err_drv_unknown_argument)
-      << A->getAsString(Args);
+  for (const Arg *A : Args.filtered(options::OPT_UNKNOWN)) {
+    auto ID = IsCLMode() ? diag::warn_drv_unknown_argument_clang_cl
+                         : diag::err_drv_unknown_argument;
+
+    Diags.Report(ID) << A->getAsString(Args);
+    ContainsError |= Diags.getDiagnosticLevel(ID, SourceLocation()) >
+                     DiagnosticsEngine::Warning;
+  }
 
   return Args;
 }
@@ -600,9 +616,8 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   // FIXME: This stuff needs to go into the Compilation, not the driver.
   bool CCCPrintPhases;
 
-  InputArgList Args = ParseArgStrings(ArgList.slice(1));
-  if (Diags.hasErrorOccurred())
-    return nullptr;
+  bool ContainsError;
+  InputArgList Args = ParseArgStrings(ArgList.slice(1), ContainsError);
 
   // Silence driver warnings if requested
   Diags.setIgnoreAllWarnings(Args.hasArg(options::OPT_w));
@@ -692,7 +707,8 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
       *UArgs, computeTargetTriple(*this, DefaultTargetTriple, *UArgs));
 
   // The compilation takes ownership of Args.
-  Compilation *C = new Compilation(*this, TC, UArgs.release(), TranslatedArgs);
+  Compilation *C = new Compilation(*this, TC, UArgs.release(), TranslatedArgs,
+                                   ContainsError);
 
   if (!HandleImmediateArgs(*C))
     return C;