C++: Optimize MissingCheckScanf/bigStep()

d10c · d10c · commit 7d24d96d802b · 2022-08-25T17:12:25.000+02:00
diff --git a/cpp/ql/src/Critical/MissingCheckScanf.ql b/cpp/ql/src/Critical/MissingCheckScanf.ql
@@ -66,16 +66,16 @@ class ScanfOutput extends Expr {
    */
   Access getAnAccess() {
     exists(Instruction dst |
-      this.bigStep(instr) = dst and
+      this.bigStep() = dst and
       dst.getAst() = result and
       valueNumber(dst) = valNum
     )
   }
 
-  private Instruction bigStep(Instruction i) {
-    result = this.smallStep(i)
+  private Instruction bigStep() {
+    result = this.smallStep(instr)
     or
-    exists(Instruction j | j = this.bigStep(i) | result = this.smallStep(j))
+    exists(Instruction i | i = this.bigStep() | result = this.smallStep(i))
   }
 
   private Instruction smallStep(Instruction i) {

Original file line number	Diff line number	Diff line change
`@@ -66,16 +66,16 @@ class ScanfOutput extends Expr {`
`66`	`66`	`*/`
`67`	`67`	`Access getAnAccess() {`
`68`	`68`	`exists(Instruction dst \|`
`69`		`- this.bigStep(instr) = dst and`
	`69`	`+ this.bigStep() = dst and`
`70`	`70`	`dst.getAst() = result and`
`71`	`71`	`valueNumber(dst) = valNum`
`72`	`72`	`)`
`73`	`73`	`}`
`74`	`74`
`75`		`- private Instruction bigStep(Instruction i) {`
`76`		`- result = this.smallStep(i)`
	`75`	`+ private Instruction bigStep() {`
	`76`	`+ result = this.smallStep(instr)`
`77`	`77`	`or`
`78`		`- exists(Instruction j \| j = this.bigStep(i) \| result = this.smallStep(j))`
	`78`	`+ exists(Instruction i \| i = this.bigStep() \| result = this.smallStep(i))`
`79`	`79`	`}`
`80`	`80`
`81`	`81`	`private Instruction smallStep(Instruction i) {`