Split libAnalysis into two libraries: libAnalysis and libChecker.

(1) libAnalysis is a generic analysis library that can be used by
    Sema.  It defines the CFG, basic dataflow analysis primitives, and
    inexpensive flow-sensitive analyses (e.g. LiveVariables).

(2) libChecker contains the guts of the static analyzer, incuding the
    path-sensitive analysis engine and domain-specific checks.

Now any clients that want to use the frontend to build their own tools
don't need to link in the entire static analyzer.

This change exposes various obvious cleanups that can be made to the
layout of files and headers in libChecker.  More changes pending.  :)

This change also exposed a layering violation between AnalysisContext
and MemRegion.  BlockInvocationContext shouldn't explicitly know about
BlockDataRegions.  For now I've removed the BlockDataRegion* from
BlockInvocationContext (removing context-sensitivity; although this
wasn't used yet).  We need to have a better way to extend
BlockInvocationContext (and any LocationContext) to add
context-sensitivty.

llvm-svn: 94406

1 files changed, 76 insertions, 0 deletions

diff --git a/clang/lib/Checker/BuiltinFunctionChecker.cpp b/clang/lib/Checker/BuiltinFunctionChecker.cpp
new file mode 100644
index 00000000000..8711492049c
--- /dev/null
+++ b/clang/lib/Checker/BuiltinFunctionChecker.cpp
@@ -0,0 +1,76 @@
+//=== BuiltinFunctionChecker.cpp --------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This checker evaluates clang builtin functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/Checker.h"
+#include "clang/Basic/Builtins.h"
+#include "llvm/ADT/StringSwitch.h"
+
+using namespace clang;
+
+namespace {
+
+class BuiltinFunctionChecker : public Checker {
+public:
+  static void *getTag() { static int tag = 0; return &tag; }
+  virtual bool EvalCallExpr(CheckerContext &C, const CallExpr *CE);
+};
+
+}
+
+void clang::RegisterBuiltinFunctionChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new BuiltinFunctionChecker());
+}
+
+bool BuiltinFunctionChecker::EvalCallExpr(CheckerContext &C,const CallExpr *CE){
+  const GRState *state = C.getState();
+  const Expr *Callee = CE->getCallee();
+  SVal L = state->getSVal(Callee);
+  const FunctionDecl *FD = L.getAsFunctionDecl();
+
+  if (!FD)
+    return false;
+
+  unsigned id = FD->getBuiltinID();
+
+  if (!id)
+    return false;
+
+  switch (id) {
+  case Builtin::BI__builtin_expect: {
+    // For __builtin_expect, just return the value of the subexpression.
+    assert (CE->arg_begin() != CE->arg_end());
+    SVal X = state->getSVal(*(CE->arg_begin()));
+    C.GenerateNode(state->BindExpr(CE, X));
+    return true;
+  }
+
+  case Builtin::BI__builtin_alloca: {
+    // FIXME: Refactor into StoreManager itself?
+    MemRegionManager& RM = C.getStoreManager().getRegionManager();
+    const MemRegion* R =
+      RM.getAllocaRegion(CE, C.getNodeBuilder().getCurrentBlockCount(),
+                         C.getPredecessor()->getLocationContext());
+
+    // Set the extent of the region in bytes. This enables us to use the
+    // SVal of the argument directly. If we save the extent in bits, we
+    // cannot represent values like symbol*8.
+    SVal Extent = state->getSVal(*(CE->arg_begin()));
+    state = C.getStoreManager().setExtent(state, R, Extent);
+    C.GenerateNode(state->BindExpr(CE, loc::MemRegionVal(R)));
+    return true;
+  }
+  }
+
+  return false;
+}