Merge pull request #723 from github/lcartey/address-perf-problems

CERT/MISRA C - Address performance issues

Author: knewbury01

c/cert/src/rules/SIG31-C/DoNotAccessSharedObjectsInSignalHandlers.ql

@@ -21,18 +21,19 @@ import codingstandards.c.Signal
  */
 class UnsafeSharedVariableAccess extends VariableAccess {
   UnsafeSharedVariableAccess() {
-    // static or thread local storage duration
-    (
-      this.getTarget() instanceof StaticStorageDurationVariable or
-      this.getTarget().isThreadLocal()
-    ) and
     // excluding `volatile sig_atomic_t` type
     not this.getType().(SigAtomicType).isVolatile() and
-    // excluding lock-free atomic objects
-    not exists(MacroInvocation mi, VariableAccess va |
-      mi.getMacroName() = "atomic_is_lock_free" and
-      mi.getExpr().getChild(0) = va.getEnclosingElement*() and
-      va.getTarget() = this.getTarget()
+    exists(Variable target | target = this.getTarget() |
+      // static or thread local storage duration
+      (
+        target instanceof StaticStorageDurationVariable or
+        target.isThreadLocal()
+      ) and
+      // excluding lock-free atomic objects
+      not exists(MacroInvocation mi, VariableAccess va | va.getTarget() = target |
+        mi.getMacroName() = "atomic_is_lock_free" and
+        mi.getExpr().getChild(0) = va.getEnclosingElement*()
+      )
     )
   }
 }

c/misra/src/rules/RULE-10-7/ImplicitConversionOfCompositeExpression.ql

@@ -18,6 +18,12 @@ import codingstandards.c.misra
 import codingstandards.c.misra.EssentialTypes
 import codingstandards.c.misra.MisraExpressions
 
+bindingset[essentialTypeLeft, essentialTypeRight]
+pragma[inline_late]
+predicate isSameEssentialTypeCategory(Type essentialTypeLeft, Type essentialTypeRight) {
+  getEssentialTypeCategory(essentialTypeLeft) = getEssentialTypeCategory(essentialTypeRight)
+}
+
 from
   OperationWithUsualArithmeticConversions arith, CompositeExpression compositeOp, Expr otherOp,
   Type compositeEssentialType, Type otherOpEssentialType
@@ -32,7 +38,7 @@ where
   // Operands of a different type category in an operation with the usual arithmetic conversions is
   // prohibited by Rule 10.4, so we only report cases here where the essential type categories are
   // the same
-  getEssentialTypeCategory(compositeEssentialType) = getEssentialTypeCategory(otherOpEssentialType)
+  isSameEssentialTypeCategory(compositeEssentialType, otherOpEssentialType)
 select arith,
   "Implicit conversion of $@ from " + compositeEssentialType + " to " + otherOpEssentialType,
   compositeOp, "composite op"

change_notes/2024-10-02-c-perf-issues.md

@@ -0,0 +1,4 @@
+ - `RULE-10-7` - `ImplicitConversionOfCompositeExpression.ql`:
+   - Improved performance on larger codebases.
+ - `SIG31-C` - `DoNotAccessSharedObjectsInSignalHandlers.ql`:
+   - Improved performance on larger codebases.