Reduce -Wuninitialized time by 22% (on sqlite) by removing the recursive AST crawl.

This is accomplished by forcing the needed expressions for -Wuninitialized to always be CFGElements in the CFG.
This allows us to remove a fair amount of the code for -Wuninitialized.

Some fallout:
- AnalysisBasedWarnings.cpp now specifically toggles the CFGBuilder to create a CFG that is suitable for -Wuninitialized.  This
is a layering violation, since the logic for -Wuninitialized is in libAnalysis.  This can be fixed with the proper refactoring.
- Some of the source locations for -Wunreachable-code warnings have shifted.  While not ideal, this is okay because that analysis
already needs some serious reworking.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135480 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index 7a14855e69..c0e271590d 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -660,6 +660,20 @@ AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
   // explosion for destrutors that can result and the compile time hit.
   AnalysisContext AC(D, 0, /*useUnoptimizedCFG=*/false, /*addehedges=*/false,
                      /*addImplicitDtors=*/true, /*addInitializers=*/true);
+  
+  // Force that certain expressions appear as CFGElements in the CFG.  This
+  // is used to speed up various analyses.
+  // FIXME: This isn't the right factoring.  This is here for initial
+  // prototyping, but we need a way for analyses to say what expressions they
+  // expect to always be CFGElements and then fill in the BuildOptions
+  // appropriately.  This is essentially a layering violation.
+  CFG::BuildOptions &buildOptions = AC.getCFGBuildOptions();
+  buildOptions.setAlwaysAdd(Stmt::BinaryOperatorClass);
+  buildOptions.setAlwaysAdd(Stmt::BlockExprClass);
+  buildOptions.setAlwaysAdd(Stmt::CStyleCastExprClass);
+  buildOptions.setAlwaysAdd(Stmt::DeclRefExprClass);
+  buildOptions.setAlwaysAdd(Stmt::ImplicitCastExprClass);
+  buildOptions.setAlwaysAdd(Stmt::UnaryOperatorClass);
 
   // Emit delayed diagnostics.
   if (!fscope->PossiblyUnreachableDiags.empty()) {