New SemanticExpr implementation

Cleans up SignAnalysis to reduce need for language-specific enhancements

Author: Dave Bartolomeo

java/ql/lib/semmle/code/java/dataflow/internal/rangeanalysis/SignAnalysisCommon.qll

@@ -374,3 +374,11 @@ predicate strictlyNegative(Expr e) {
   not exprSign(e) = TPos() and
   not exprSign(e) = TZero()
 }
+
+/**
+ * Expose some predicates for testing purposes without making them implicitly public to any module
+ * that imports this file.
+ */
+module SignAnalysisCommonTest {
+  predicate testSsaDefSign = ssaDefSign/1;
+}

java/ql/lib/semmle/code/java/semantic/SemanticCFG.qll

@@ -4,6 +4,7 @@
 
 private import java
 private import SemanticExpr
+private import SemanticExprSpecific
 
 private newtype TSemBasicBlock = MkSemBasicBlock(BasicBlock block)
 
@@ -14,6 +15,8 @@ class SemBasicBlock extends TSemBasicBlock {
 
   final string toString() { result = block.toString() }
 
+  final Location getLocation() { result = block.getLocation() }
+
   final predicate bbDominates(SemBasicBlock otherBlock) {
     block.bbDominates(getJavaBasicBlock(otherBlock))
   }