Merge pull request #2341 from aschackmull/java/cached-tostring-perf-fixes

yo-h · web-flow · commit 69a263280609 · 2019-12-16T22:01:35.000-05:00
Java: Fix a number of performance issues when toString is cached.
diff --git a/java/ql/src/Violations of Best Practice/Boxed Types/BoxedVariable.ql b/java/ql/src/Violations of Best Practice/Boxed Types/BoxedVariable.ql
@@ -39,6 +39,9 @@ predicate notDeliberatelyBoxed(LocalBoxedVar v) {
   )
 }
 
+pragma[nomagic]
+int callableGetNumberOfParameters(Callable c) { result = c.getNumberOfParameters() }
+
 /**
  * Replacing the type of a boxed variable with the corresponding primitive type may affect
  * overload resolution. If this is the case then the boxing is most likely intentional and
@@ -52,7 +55,7 @@ predicate affectsOverload(LocalBoxedVar v) {
     c1.getParameterType(i) instanceof RefType and
     c2.getParameterType(i) instanceof PrimitiveType and
     c1.getName() = c2.getName() and
-    c1.getNumberOfParameters() = c2.getNumberOfParameters()
+    callableGetNumberOfParameters(c1) = callableGetNumberOfParameters(c2)
   )
 }
 
diff --git a/java/ql/src/semmle/code/Location.qll b/java/ql/src/semmle/code/Location.qll
@@ -84,6 +84,7 @@ class Top extends @top {
   int getNumberOfCommentLines() { numlines(this, _, _, result) }
 
   /** Gets a textual representation of this element. */
+  cached
   string toString() { hasName(this, result) }
 }
 
diff --git a/java/ql/src/semmle/code/java/deadcode/DeadCode.qll b/java/ql/src/semmle/code/java/deadcode/DeadCode.qll
@@ -301,7 +301,7 @@ class RootdefCallable extends Callable {
   }
 }
 
-pragma[noinline]
+pragma[nomagic]
 private predicate overrideAccess(Callable c, int i) {
   exists(Method m | m.overridesOrInstantiates+(c) | exists(m.getParameter(i).getAnAccess()))
 }
diff --git a/java/ql/src/semmle/code/java/frameworks/gwt/GWT.qll b/java/ql/src/semmle/code/java/frameworks/gwt/GWT.qll
@@ -61,19 +61,29 @@ class ClientSideGwtCompilationUnit extends GwtCompilationUnit {
   }
 }
 
-/** Auxiliary predicate: `jsni` is a JSNI comment associated with method `m`. */
-private predicate jsniComment(Javadoc jsni, Method m) {
+private predicate jsni(Javadoc jsni, File file, int startline) {
   // The comment must start with `-{` ...
   jsni.getChild(0).getText().matches("-{%") and
   // ... and it must end with `}-`.
   jsni.getChild(jsni.getNumChild() - 1).getText().matches("%}-") and
-  // The associated callable must be marked as `native` ...
+  file = jsni.getFile() and
+  startline = jsni.getLocation().getStartLine()
+}
+
+private predicate nativeMethodLines(Method m, File file, int line) {
   m.isNative() and
-  // ... and the comment has to be contained in `m`.
-  jsni.getFile() = m.getFile() and
-  jsni.getLocation().getStartLine() in [m.getLocation().getStartLine() .. m
-          .getLocation()
-          .getEndLine()]
+  file = m.getFile() and
+  line in [m.getLocation().getStartLine() .. m.getLocation().getEndLine()]
+}
+
+/** Auxiliary predicate: `jsni` is a JSNI comment associated with method `m`. */
+private predicate jsniComment(Javadoc jsni, Method m) {
+  exists(File file, int line |
+    jsni(jsni, file, line) and
+    // The associated callable must be marked as `native`
+    // and the comment has to be contained in `m`.
+    nativeMethodLines(m, file, line)
+  )
 }
 
 /**

Original file line number	Diff line number	Diff line change
`@@ -39,6 +39,9 @@ predicate notDeliberatelyBoxed(LocalBoxedVar v) {`
`39`	`39`	`)`
`40`	`40`	`}`
`41`	`41`
	`42`	`+pragma[nomagic]`
	`43`	`+int callableGetNumberOfParameters(Callable c) { result = c.getNumberOfParameters() }`
	`44`	`+`
`42`	`45`	`/**`
`43`	`46`	`* Replacing the type of a boxed variable with the corresponding primitive type may affect`
`44`	`47`	`* overload resolution. If this is the case then the boxing is most likely intentional and`
`@@ -52,7 +55,7 @@ predicate affectsOverload(LocalBoxedVar v) {`
`52`	`55`	`c1.getParameterType(i) instanceof RefType and`
`53`	`56`	`c2.getParameterType(i) instanceof PrimitiveType and`
`54`	`57`	`c1.getName() = c2.getName() and`
`55`		`- c1.getNumberOfParameters() = c2.getNumberOfParameters()`
	`58`	`+ callableGetNumberOfParameters(c1) = callableGetNumberOfParameters(c2)`
`56`	`59`	`)`
`57`	`60`	`}`
`58`	`61`
Original file line number	Diff line number	Diff line change
`@@ -84,6 +84,7 @@ class Top extends @top {`
`84`	`84`	`int getNumberOfCommentLines() { numlines(this, _, _, result) }`
`85`	`85`
`86`	`86`	`/** Gets a textual representation of this element. */`
	`87`	`+ cached`
`87`	`88`	`string toString() { hasName(this, result) }`
`88`	`89`	`}`
`89`	`90`
Original file line number	Diff line number	Diff line change
`@@ -301,7 +301,7 @@ class RootdefCallable extends Callable {`
`301`	`301`	`}`
`302`	`302`	`}`
`303`	`303`
`304`		`-pragma[noinline]`
	`304`	`+pragma[nomagic]`
`305`	`305`	`private predicate overrideAccess(Callable c, int i) {`
`306`	`306`	`exists(Method m \| m.overridesOrInstantiates+(c) \| exists(m.getParameter(i).getAnAccess()))`
`307`	`307`	`}`