Update Clang for 3.5 rebase (r209713).
Change-Id: I8c9133b0f8f776dc915f270b60f94962e771bc83
diff --git a/lib/Analysis/ThreadSafetyLogical.cpp b/lib/Analysis/ThreadSafetyLogical.cpp
new file mode 100644
index 0000000..51a8077
--- /dev/null
+++ b/lib/Analysis/ThreadSafetyLogical.cpp
@@ -0,0 +1,112 @@
+//===- ThreadSafetyLogical.cpp ---------------------------------*- 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 a representation for logical expressions with SExpr leaves
+// that are used as part of fact-checking capability expressions.
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/Analyses/ThreadSafetyLogical.h"
+
+using namespace llvm;
+using namespace clang::threadSafety::lexpr;
+
+// Implication. We implement De Morgan's Laws by maintaining LNeg and RNeg
+// to keep track of whether LHS and RHS are negated.
+static bool implies(const LExpr *LHS, bool LNeg, const LExpr *RHS, bool RNeg) {
+ // In comments below, we write => for implication.
+
+ // Calculates the logical AND implication operator.
+ const auto LeftAndOperator = [=](const BinOp *A) {
+ return implies(A->left(), LNeg, RHS, RNeg) &&
+ implies(A->right(), LNeg, RHS, RNeg);
+ };
+ const auto RightAndOperator = [=](const BinOp *A) {
+ return implies(LHS, LNeg, A->left(), RNeg) &&
+ implies(LHS, LNeg, A->right(), RNeg);
+ };
+
+ // Calculates the logical OR implication operator.
+ const auto LeftOrOperator = [=](const BinOp *A) {
+ return implies(A->left(), LNeg, RHS, RNeg) ||
+ implies(A->right(), LNeg, RHS, RNeg);
+ };
+ const auto RightOrOperator = [=](const BinOp *A) {
+ return implies(LHS, LNeg, A->left(), RNeg) ||
+ implies(LHS, LNeg, A->right(), RNeg);
+ };
+
+ // Recurse on right.
+ switch (RHS->kind()) {
+ case LExpr::And:
+ // When performing right recursion:
+ // C => A & B [if] C => A and C => B
+ // When performing right recursion (negated):
+ // C => !(A & B) [if] C => !A | !B [===] C => !A or C => !B
+ return RNeg ? RightOrOperator(cast<And>(RHS))
+ : RightAndOperator(cast<And>(RHS));
+ case LExpr::Or:
+ // When performing right recursion:
+ // C => (A | B) [if] C => A or C => B
+ // When performing right recursion (negated):
+ // C => !(A | B) [if] C => !A & !B [===] C => !A and C => !B
+ return RNeg ? RightAndOperator(cast<Or>(RHS))
+ : RightOrOperator(cast<Or>(RHS));
+ case LExpr::Not:
+ // Note that C => !A is very different from !(C => A). It would be incorrect
+ // to return !implies(LHS, RHS).
+ return implies(LHS, LNeg, cast<Not>(RHS)->exp(), !RNeg);
+ case LExpr::Terminal:
+ // After reaching the terminal, it's time to recurse on the left.
+ break;
+ }
+
+ // RHS is now a terminal. Recurse on Left.
+ switch (LHS->kind()) {
+ case LExpr::And:
+ // When performing left recursion:
+ // A & B => C [if] A => C or B => C
+ // When performing left recursion (negated):
+ // !(A & B) => C [if] !A | !B => C [===] !A => C and !B => C
+ return LNeg ? LeftAndOperator(cast<And>(LHS))
+ : LeftOrOperator(cast<And>(LHS));
+ case LExpr::Or:
+ // When performing left recursion:
+ // A | B => C [if] A => C and B => C
+ // When performing left recursion (negated):
+ // !(A | B) => C [if] !A & !B => C [===] !A => C or !B => C
+ return LNeg ? LeftOrOperator(cast<Or>(LHS))
+ : LeftAndOperator(cast<Or>(LHS));
+ case LExpr::Not:
+ // Note that A => !C is very different from !(A => C). It would be incorrect
+ // to return !implies(LHS, RHS).
+ return implies(cast<Not>(LHS)->exp(), !LNeg, RHS, RNeg);
+ case LExpr::Terminal:
+ // After reaching the terminal, it's time to perform identity comparisons.
+ break;
+ }
+
+ // A => A
+ // !A => !A
+ if (LNeg != RNeg)
+ return false;
+
+ // FIXME -- this should compare SExprs for equality, not pointer equality.
+ return cast<Terminal>(LHS)->expr() == cast<Terminal>(RHS)->expr();
+}
+
+namespace clang {
+namespace threadSafety {
+namespace lexpr {
+
+bool implies(const LExpr *LHS, const LExpr *RHS) {
+ // Start out by assuming that LHS and RHS are not negated.
+ return ::implies(LHS, false, RHS, false);
+}
+}
+}
+}