Merge pull request #12 from pavgust/imp/c-locations

Simplify C locations handling

Author: jbj

cpp/ql/src/definitions.qll

@@ -102,15 +102,16 @@ private predicate constructorCallStartLoc(ConstructorCall cc, File f, int line,
 
 /**
  * Holds if `f`, `line`, `column` indicate the start character
- * of `tm`. 
+ * of `tm`, which mentions `t`.
  */
-private predicate typeMentionStartLoc(TypeMention tm, File f, int line, int column) {
+private predicate typeMentionStartLoc(TypeMention tm, Type t, File f, int line, int column) {
   exists(Location l |
     l = tm.getLocation() and
     l.getFile() = f and
     l.getStartLine() = line and
     l.getStartColumn() = column
-  )
+  ) and
+  t = tm.getMentionedType()
 }
 
 /**
@@ -119,7 +120,7 @@ private predicate typeMentionStartLoc(TypeMention tm, File f, int line, int colu
 private cached predicate constructorCallTypeMention(ConstructorCall cc, TypeMention tm) {
   exists(File f, int line, int column |
     constructorCallStartLoc(cc, f, line, column) and
-    typeMentionStartLoc(tm, f, line, column)
+    typeMentionStartLoc(tm, _, f, line, column)
   )
 }
 
@@ -155,15 +156,16 @@ Top definitionOf(Top e, string kind) {
       kind = "T" and
       e.(TypeMention).getMentionedType() = result and
       not constructorCallTypeMention(_, e) and // handled elsewhere
-
-      // multiple mentions can be generated when a typedef is used.  Exclude
-      // all but the originating typedef.
-      not exists(TypeMention tm, File f, int startline, int startcol |
-        typeMentionStartLoc(e, f, startline, startcol) and
-        typeMentionStartLoc(tm, f, startline, startcol) and
-        (
-          e.(TypeMention).getMentionedType() = tm.getMentionedType().(TypedefType).getBaseType() or
-          e.(TypeMention).getMentionedType() = tm.getMentionedType().(TypedefType).getBaseType().(SpecifiedType).getBaseType()
+      // Multiple type mentions can be generated when a typedef is used, and
+      // in such cases we want to exclude all but the originating typedef.
+      not exists(Type secondary |
+        exists(TypeMention tm, File f, int startline, int startcol |
+          typeMentionStartLoc(e, result, f, startline, startcol) and
+          typeMentionStartLoc(tm, secondary, f, startline, startcol) and
+          (
+            result = secondary.(TypedefType).getBaseType() or
+            result = secondary.(TypedefType).getBaseType().(SpecifiedType).getBaseType()
+          )
         )
       )
     ) or (
@@ -186,7 +188,7 @@ Top definitionOf(Top e, string kind) {
       not exists(MacroInvocation mi, Location l1, Location l2 |
         l1 = e.(Include).getLocation() and
         l2 = mi.getLocation() and
-        l1.getFile() = l2.getFile() and
+        l1.getContainer() = l2.getContainer() and
         l1.getStartLine() = l2.getStartLine()
         // (an #include directive must be always on it's own line)
       )

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

@@ -8,9 +8,7 @@ class Location extends @location {
 
   /** Gets the container corresponding to this location. */
   Container getContainer() {
-    locations_default(this,result,_,_,_,_) or
-    locations_stmt(this,result,_,_,_,_) or
-    locations_expr(this,result,_,_,_,_)
+    this.fullLocationInfo(result, _, _, _, _)
   }
 
   /** Gets the file corresponding to this location, if any. */
@@ -20,30 +18,22 @@ class Location extends @location {
 
   /** Gets the start line of this location. */
   int getStartLine() {
-    locations_default(this,_,result,_,_,_) or
-    locations_stmt(this,_,result,_,_,_) or
-    locations_expr(this,_,result,_,_,_)
-  }
-
-  /** Gets the end line of this location. */
-  int getEndLine() {
-    locations_default(this,_,_,_,result,_) or
-    locations_stmt(this,_,_,_,result,_) or
-    locations_expr(this,_,_,_,result,_)
+    this.fullLocationInfo(_, result, _, _, _)
   }
 
   /** Gets the start column of this location. */
   int getStartColumn() {
-    locations_default(this,_,_,result,_,_) or
-    locations_stmt(this,_,_,result,_,_) or
-    locations_expr(this,_,_,result,_,_)
+    this.fullLocationInfo(_, _, result, _, _)
+  }
+
+  /** Gets the end line of this location. */
+  int getEndLine() {
+    this.fullLocationInfo(_, _, _, result, _)
   }
 
   /** Gets the end column of this location. */
   int getEndColumn() {
-    locations_default(this,_,_,_,_,result) or
-    locations_stmt(this,_,_,_,_,result) or
-    locations_expr(this,_,_,_,_,result)
+    this.fullLocationInfo(_, _, _, _, result)
   }
 
   /**
@@ -58,6 +48,20 @@ class Location extends @location {
     )
   }
 
+  /**
+   * Holds if this element is in the specified container.
+   * The location spans column `startcolumn` of line `startline` to
+   * column `endcolumn` of line `endline`.
+   *
+   * This predicate is similar to `hasLocationInfo`, but exposes the `Container`
+   * entity, rather than merely its path.
+   */
+  predicate fullLocationInfo(
+    Container container, int startline, int startcolumn, int endline, int endcolumn) {
+    locations_default(this, container, startline,  startcolumn, endline, endcolumn) or
+    locations_expr(this, container, startline,  startcolumn, endline, endcolumn) or
+    locations_stmt(this, container, startline,  startcolumn, endline, endcolumn)
+  }
 
   /**
    * Holds if this element is at the specified location.
@@ -68,7 +72,9 @@ class Location extends @location {
    */
   predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn) {
-    none()
+    exists(Container f
+    | this.fullLocationInfo(f,startline,startcolumn,endline,endcolumn)
+    | filepath = f.getAbsolutePath())
   }
 
   /** Holds if `this` comes on a line strictly before `l`. */
@@ -108,34 +114,13 @@ class Location extends @location {
  * A location of an element. Not used for expressions or statements, which
  * instead use LocationExpr and LocationStmt respectively.
  */
-library class LocationDefault extends Location, @location_default {
-  override predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn) {
-    exists(Container f
-    | locations_default(this,f,startline,startcolumn,endline,endcolumn)
-    | filepath = f.getAbsolutePath())
-  }
-}
+library class LocationDefault extends Location, @location_default {}
 
 /** A location of a statement. */
-library class LocationStmt extends Location, @location_stmt {
-  override predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn) {
-    exists(Container f
-    | locations_stmt(this,f,startline,startcolumn,endline,endcolumn)
-    | filepath = f.getAbsolutePath())
-  }
-}
+library class LocationStmt extends Location, @location_stmt {}
 
 /** A location of an expression. */
-library class LocationExpr extends Location, @location_expr {
-  override predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn) {
-    exists(Container f
-    | locations_expr(this,f,startline,startcolumn,endline,endcolumn)
-    | filepath = f.getAbsolutePath())
-  }
-}
+library class LocationExpr extends Location, @location_expr {}
 
 /**
  * Gets the length of the longest line in file `f`.