[PATCH] D25596: alpha.core.Conversion - Fix false positive for 'U32 += S16; ' expression, that is not unsafe

[Daniel Marjamäki via cfe-commits]

danielmarjamaki created this revision.
danielmarjamaki added a reviewer: NoQ.
danielmarjamaki added subscribers: cfe-commits, xazax.hun, dcoughlin.
danielmarjamaki set the repository for this revision to rL LLVM.

This patch fix false positives for loss of sign in addition and subtraction assignment operators.


Repository:
  rL LLVM

https://reviews.llvm.org/D25596

Files:
  lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
  test/Analysis/conversion.c


Index: test/Analysis/conversion.c
===================================================================
--- test/Analysis/conversion.c
+++ test/Analysis/conversion.c
@@ -77,6 +77,10 @@
 void dontwarn5() {
   signed S = -32;
   U8 = S + 10;
+
+  unsigned  x = 100;
+  signed short delta = -1;
+  x += delta;
 }
 
 
Index: lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
+++ lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
@@ -73,10 +73,13 @@
   // Loss of sign/precision in binary operation.
   if (const auto *B = dyn_cast<BinaryOperator>(Parent)) {
     BinaryOperator::Opcode Opc = B->getOpcode();
-    if (Opc == BO_Assign || Opc == BO_AddAssign || Opc == BO_SubAssign ||
-        Opc == BO_MulAssign) {
-      LossOfSign = isLossOfSign(Cast, C);
-      LossOfPrecision = isLossOfPrecision(Cast, C);
+    if (B->isAssignmentOp()) {
+      if (Opc == BO_Assign || Opc == BO_AddAssign || Opc == BO_SubAssign ||
+          Opc == BO_MulAssign || Opc == BO_OrAssign || Opc == BO_XorAssign)
+        LossOfPrecision = isLossOfPrecision(Cast, C);
+      if (Opc == BO_Assign || Opc == BO_MulAssign || Opc == BO_DivAssign ||
+          Opc == BO_RemAssign)
+        LossOfSign = isLossOfSign(Cast, C);
     } else if (B->isRelationalOp() || B->isMultiplicativeOp()) {
       LossOfSign = isLossOfSign(Cast, C);
     }
@@ -153,7 +156,7 @@
 }
 
 bool ConversionChecker::isLossOfPrecision(const ImplicitCastExpr *Cast,
-                                        CheckerContext &C) const {
+                                          CheckerContext &C) const {
   // Don't warn about explicit loss of precision.
   if (Cast->isEvaluatable(C.getASTContext()))
     return false;
@@ -177,7 +180,7 @@
 }
 
 bool ConversionChecker::isLossOfSign(const ImplicitCastExpr *Cast,
-                                   CheckerContext &C) const {
+                                     CheckerContext &C) const {
   QualType CastType = Cast->getType();
   QualType SubType = Cast->IgnoreParenImpCasts()->getType();
 


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