Bug 1324239 - Refactor the clang plugin; r=mystor

This patch mostly just splits up clang-plugin.cpp into separate files for
different classes or helpers.

build/clang-plugin/NonParamInsideFunctionDeclChecker.cpp

@@ -0,0 +1,70 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "NonParamInsideFunctionDeclChecker.h"
+#include "CustomMatchers.h"
+
+void NonParamInsideFunctionDeclChecker::registerMatcher(MatchFinder& AstMatcher) {
+  AstMatcher.addMatcher(
+      functionDecl(anyOf(allOf(isDefinition(),
+                               hasAncestor(classTemplateSpecializationDecl()
+                                               .bind("spec"))),
+                         isDefinition()))
+          .bind("func"),
+      this);
+  AstMatcher.addMatcher(
+      lambdaExpr().bind("lambda"),
+      this);
+}
+
+void NonParamInsideFunctionDeclChecker::run(
+    const MatchFinder::MatchResult &Result) {
+  static DenseSet<const FunctionDecl*> CheckedFunctionDecls;
+
+  const FunctionDecl *func = Result.Nodes.getNodeAs<FunctionDecl>("func");
+  if (!func) {
+    const LambdaExpr *lambda = Result.Nodes.getNodeAs<LambdaExpr>("lambda");
+    if (lambda) {
+      func = lambda->getCallOperator();
+    }
+  }
+
+  if (!func) {
+    return;
+  }
+
+  if (func->isDeleted()) {
+    return;
+  }
+
+  // Don't report errors on the same declarations more than once.
+  if (CheckedFunctionDecls.count(func)) {
+    return;
+  }
+  CheckedFunctionDecls.insert(func);
+
+  const ClassTemplateSpecializationDecl *Spec =
+      Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("spec");
+
+  DiagnosticsEngine &Diag = Result.Context->getDiagnostics();
+  unsigned ErrorID = Diag.getDiagnosticIDs()->getCustomDiagID(
+      DiagnosticIDs::Error, "Type %0 must not be used as parameter");
+  unsigned NoteID = Diag.getDiagnosticIDs()->getCustomDiagID(
+      DiagnosticIDs::Note, "Please consider passing a const reference instead");
+  unsigned SpecNoteID = Diag.getDiagnosticIDs()->getCustomDiagID(
+      DiagnosticIDs::Note, "The bad argument was passed to %0 here");
+
+  for (ParmVarDecl *p : func->parameters()) {
+    QualType T = p->getType().withoutLocalFastQualifiers();
+    if (NonParam.hasEffectiveAnnotation(T)) {
+      Diag.Report(p->getLocation(), ErrorID) << T;
+      Diag.Report(p->getLocation(), NoteID);
+
+      if (Spec) {
+        Diag.Report(Spec->getPointOfInstantiation(), SpecNoteID)
+          << Spec->getSpecializedTemplate();
+      }
+    }
+  }
+}