Refactor CFG-based warnings in Sema to be run by a worked object called AnalysisBasedWarnings.

This object controls when the warnings are executed, allowing the client code
in Sema to selectively disable warnings as needed.

Centralizing the logic for analysis-based warnings allows us to optimize
when and how they are run.

Along the way, remove the redundant logic for the 'check fall-through' warning
for blocks; now the same logic is used for both blocks and functions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@99085 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 0 deletions

diff --git a/lib/Sema/AnalysisBasedWarnings.h b/lib/Sema/AnalysisBasedWarnings.h
new file mode 100644
index 0000000000..39da1b14d4
--- /dev/null
+++ b/lib/Sema/AnalysisBasedWarnings.h
@@ -0,0 +1,35 @@
+//=- AnalysisBasedWarnings.h - Sema warnings based on libAnalysis -*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines AnalysisBasedWarnings, a worker object used by Sema
+// that issues warnings based on dataflow-analysis.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_ANALYSIS_WARNINGS_H
+#define LLVM_CLANG_SEMA_ANALYSIS_WARNINGS_H
+
+namespace clang { namespace sema {
+
+class AnalysisBasedWarnings {
+  Sema &S;
+  // The warnings to run.
+  unsigned enableCheckFallThrough : 1;
+  unsigned enableCheckUnreachable : 1;
+  
+public:
+
+  AnalysisBasedWarnings(Sema &s);
+  void IssueWarnings(const Decl *D, QualType BlockTy = QualType());
+  
+  void disableCheckFallThrough() { enableCheckFallThrough = 0; }
+};
+  
+}} // end namespace clang::sema
+
+#endif