C++: Move a couple predicates into Exclusions.qll

Author: dave-bartolomeo

cpp/ql/src/Likely Bugs/Arithmetic/PointlessComparison.ql

@@ -12,6 +12,7 @@
  *       readability
  */
 import cpp
+private import semmle.code.cpp.commons.Exclusions
 private import semmle.code.cpp.rangeanalysis.PointlessComparison
 private import semmle.code.cpp.rangeanalysis.RangeAnalysisUtils
 import UnsignedGEZero

cpp/ql/src/Likely Bugs/Likely Typos/ExprHasNoEffect.ql

@@ -11,6 +11,7 @@
  *       external/cwe/cwe-561
  */
 import cpp
+private import semmle.code.cpp.commons.Exclusions
 
 class PureExprInVoidContext extends ExprInVoidContext {
   PureExprInVoidContext() { this.isPure() }

cpp/ql/src/semmle/code/cpp/Preprocessor.qll

@@ -221,58 +221,3 @@ class PreprocessorPragma extends PreprocessorDirective, @ppd_pragma {
 class PreprocessorLine extends PreprocessorDirective, @ppd_line {
   override string toString() { result = "#line " + this.getHead() }
 }
-
-/**
- * Holds if the preprocessor branch `pbd` is on line `pbdStartLine` in file `file`.
- */
-private predicate pbdLocation(PreprocessorBranchDirective pbd, string file, int pbdStartLine) {
-  pbd.getLocation().hasLocationInfo(file, pbdStartLine, _, _, _)
-}
-
-/**
- * Holds if the body of the function `f` is on lines `fBlockStartLine` to `fBlockEndLine` in file `file`.
- */
-private predicate functionLocation(Function f, string file, int fBlockStartLine, int fBlockEndLine) {
-  f.getBlock().getLocation().hasLocationInfo(file, fBlockStartLine, _, fBlockEndLine, _)
-}
-
-/**
- * Holds if the function `f` is inside a preprocessor branch that may have code in another arm.
- */
-predicate functionDefinedInIfDef(Function f) {
-  exists(PreprocessorBranchDirective pbd, string file, int pbdStartLine, int pbdEndLine, int fBlockStartLine,
-      int fBlockEndLine  |
-    functionLocation(f, file, fBlockStartLine, fBlockEndLine) and
-    pbdLocation(pbd, file, pbdStartLine) and
-    pbdLocation(pbd.getNext(), file, pbdEndLine) and
-    pbdStartLine <= fBlockStartLine and
-    pbdEndLine >= fBlockEndLine and
-    // pbd is a preprocessor branch where multiple branches exist
-    (
-      pbd.getNext() instanceof PreprocessorElse or
-      pbd instanceof PreprocessorElse or
-      pbd.getNext() instanceof PreprocessorElif or
-      pbd instanceof PreprocessorElif
-    )
-  )
-}
-
-/**
- * Holds if the function `f` contains code excluded by the preprocessor.
- */
-predicate functionContainsDisabledCode(Function f) {
-  // `f` contains a preprocessor branch that was not taken
-  exists(PreprocessorBranchDirective pbd, string file, int pbdStartLine, int fBlockStartLine, int fBlockEndLine |
-    functionLocation(f, file, fBlockStartLine, fBlockEndLine) and
-    pbdLocation(pbd, file, pbdStartLine) and
-    pbdStartLine <= fBlockEndLine and
-    pbdStartLine >= fBlockStartLine and
-    (
-      pbd.(PreprocessorBranch).wasNotTaken() or
-
-      // an else either was not taken, or it's corresponding branch
-      // was not taken.
-      pbd instanceof PreprocessorElse
-    )
-  )
-}

cpp/ql/src/semmle/code/cpp/commons/Exclusions.qll

@@ -0,0 +1,60 @@
+/**
+ * Common predicates used to exclude results from a query based on heuristics.
+ */
+
+import cpp
+
+/**
+ * Holds if the preprocessor branch `pbd` is on line `pbdStartLine` in file `file`.
+ */
+private predicate pbdLocation(PreprocessorBranchDirective pbd, string file, int pbdStartLine) {
+  pbd.getLocation().hasLocationInfo(file, pbdStartLine, _, _, _)
+}
+
+/**
+ * Holds if the body of the function `f` is on lines `fBlockStartLine` to `fBlockEndLine` in file `file`.
+ */
+private predicate functionLocation(Function f, string file, int fBlockStartLine, int fBlockEndLine) {
+  f.getBlock().getLocation().hasLocationInfo(file, fBlockStartLine, _, fBlockEndLine, _)
+}
+
+/**
+ * Holds if the function `f` is inside a preprocessor branch that may have code in another arm.
+ */
+predicate functionDefinedInIfDef(Function f) {
+  exists(PreprocessorBranchDirective pbd, string file, int pbdStartLine, int pbdEndLine, int fBlockStartLine,
+      int fBlockEndLine  |
+    functionLocation(f, file, fBlockStartLine, fBlockEndLine) and
+    pbdLocation(pbd, file, pbdStartLine) and
+    pbdLocation(pbd.getNext(), file, pbdEndLine) and
+    pbdStartLine <= fBlockStartLine and
+    pbdEndLine >= fBlockEndLine and
+    // pbd is a preprocessor branch where multiple branches exist
+    (
+      pbd.getNext() instanceof PreprocessorElse or
+      pbd instanceof PreprocessorElse or
+      pbd.getNext() instanceof PreprocessorElif or
+      pbd instanceof PreprocessorElif
+    )
+  )
+}
+
+/**
+ * Holds if the function `f` contains code excluded by the preprocessor.
+ */
+predicate functionContainsDisabledCode(Function f) {
+  // `f` contains a preprocessor branch that was not taken
+  exists(PreprocessorBranchDirective pbd, string file, int pbdStartLine, int fBlockStartLine, int fBlockEndLine |
+    functionLocation(f, file, fBlockStartLine, fBlockEndLine) and
+    pbdLocation(pbd, file, pbdStartLine) and
+    pbdStartLine <= fBlockEndLine and
+    pbdStartLine >= fBlockStartLine and
+    (
+      pbd.(PreprocessorBranch).wasNotTaken() or
+
+      // an else either was not taken, or it's corresponding branch
+      // was not taken.
+      pbd instanceof PreprocessorElse
+    )
+  )
+}