Reapply r207477 and r207479 without cyclic dependency

Fixed by moving ProcessWarningOptions from Frontend into Basic. All of
the dependencies for ProcessWarningOptions were already in Basic, so
this was a small change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@207549 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 200 insertions, 0 deletions

diff --git a/lib/Basic/Warnings.cpp b/lib/Basic/Warnings.cpp
new file mode 100644
index 0000000000..b09e69aeca
--- /dev/null
+++ b/lib/Basic/Warnings.cpp
@@ -0,0 +1,200 @@
+//===--- Warnings.cpp - C-Language Front-end ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Command line warning options handler.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is responsible for handling all warning options. This includes
+// a number of -Wfoo options and their variants, which are driven by TableGen-
+// generated data, and the special cases -pedantic, -pedantic-errors, -w,
+// -Werror and -Wfatal-errors.
+//
+// Each warning option controls any number of actual warnings.
+// Given a warning option 'foo', the following are valid:
+//    -Wfoo, -Wno-foo, -Werror=foo, -Wfatal-errors=foo
+//
+#include "clang/Basic/AllDiagnostics.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include <algorithm>
+#include <cstring>
+#include <utility>
+using namespace clang;
+
+// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
+// opts
+static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags,
+                                  StringRef Prefix, StringRef Opt,
+                                  bool isPositive) {
+  StringRef Suggestion = DiagnosticIDs::getNearestWarningOption(Opt);
+  if (!Suggestion.empty())
+    Diags.Report(isPositive? diag::warn_unknown_warning_option_suggest :
+                             diag::warn_unknown_negative_warning_option_suggest)
+      << (Prefix.str() += Opt) << (Prefix.str() += Suggestion);
+  else
+    Diags.Report(isPositive? diag::warn_unknown_warning_option :
+                             diag::warn_unknown_negative_warning_option)
+      << (Prefix.str() += Opt);
+}
+
+void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,
+                                  const DiagnosticOptions &Opts,
+                                  bool ReportDiags) {
+  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
+  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
+  Diags.setShowOverloads(Opts.getShowOverloads());
+
+  Diags.setElideType(Opts.ElideType);
+  Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
+  Diags.setShowColors(Opts.ShowColors);
+ 
+  // Handle -ferror-limit
+  if (Opts.ErrorLimit)
+    Diags.setErrorLimit(Opts.ErrorLimit);
+  if (Opts.TemplateBacktraceLimit)
+    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
+  if (Opts.ConstexprBacktraceLimit)
+    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
+
+  // 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
+  // around with them explicitly.
+  if (Opts.PedanticErrors)
+    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Error);
+  else if (Opts.Pedantic)
+    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Warn);
+  else
+    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Ignore);
+
+  SmallVector<diag::kind, 10> _Diags;
+  const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
+    Diags.getDiagnosticIDs();
+  // We parse the warning options twice.  The first pass sets diagnostic state,
+  // while the second pass reports warnings/errors.  This has the effect that
+  // we follow the more canonical "last option wins" paradigm when there are 
+  // conflicting options.
+  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
+    bool SetDiagnostic = (Report == 0);
+
+    // If we've set the diagnostic state and are not reporting diagnostics then
+    // we're done.
+    if (!SetDiagnostic && !ReportDiags)
+      break;
+
+    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
+      StringRef Opt = Opts.Warnings[i];
+      StringRef OrigOpt = Opts.Warnings[i];
+
+      // Treat -Wformat=0 as an alias for -Wno-format.
+      if (Opt == "format=0")
+        Opt = "no-format";
+
+      // Check to see if this warning starts with "no-", if so, this is a
+      // negative form of the option.
+      bool isPositive = true;
+      if (Opt.startswith("no-")) {
+        isPositive = false;
+        Opt = Opt.substr(3);
+      }
+
+      // Figure out how this option affects the warning.  If -Wfoo, map the
+      // diagnostic to a warning, if -Wno-foo, map it to ignore.
+      diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
+      
+      // -Wsystem-headers is a special case, not driven by the option table.  It
+      // cannot be controlled with -Werror.
+      if (Opt == "system-headers") {
+        if (SetDiagnostic)
+          Diags.setSuppressSystemWarnings(!isPositive);
+        continue;
+      }
+      
+      // -Weverything is a special case as well.  It implicitly enables all
+      // warnings, including ones not explicitly in a warning group.
+      if (Opt == "everything") {
+        if (SetDiagnostic) {
+          if (isPositive) {
+            Diags.setEnableAllWarnings(true);
+          } else {
+            Diags.setEnableAllWarnings(false);
+            Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
+          }
+        }
+        continue;
+      }
+      
+      // -Werror/-Wno-error is a special case, not controlled by the option 
+      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
+      if (Opt.startswith("error")) {
+        StringRef Specifier;
+        if (Opt.size() > 5) {  // Specifier must be present.
+          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
+            if (Report)
+              Diags.Report(diag::warn_unknown_warning_specifier)
+                << "-Werror" << ("-W" + OrigOpt.str());
+            continue;
+          }
+          Specifier = Opt.substr(6);
+        }
+        
+        if (Specifier.empty()) {
+          if (SetDiagnostic)
+            Diags.setWarningsAsErrors(isPositive);
+          continue;
+        }
+        
+        if (SetDiagnostic) {
+          // Set the warning as error flag for this specifier.
+          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
+        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
+          EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
+        }
+        continue;
+      }
+      
+      // -Wfatal-errors is yet another special case.
+      if (Opt.startswith("fatal-errors")) {
+        StringRef Specifier;
+        if (Opt.size() != 12) {
+          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
+            if (Report)
+              Diags.Report(diag::warn_unknown_warning_specifier)
+                << "-Wfatal-errors" << ("-W" + OrigOpt.str());
+            continue;
+          }
+          Specifier = Opt.substr(13);
+        }
+
+        if (Specifier.empty()) {
+          if (SetDiagnostic)
+            Diags.setErrorsAsFatal(isPositive);
+          continue;
+        }
+        
+        if (SetDiagnostic) {
+          // Set the error as fatal flag for this specifier.
+          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
+        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
+          EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
+                                 isPositive);
+        }
+        continue;
+      }
+      
+      if (Report) {
+        if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
+          EmitUnknownDiagWarning(Diags, isPositive ? "-W" : "-Wno-", Opt,
+                                 isPositive);
+      } else {
+        Diags.setDiagnosticGroupMapping(Opt, Mapping);
+      }
+    }
+  }
+}