This revision was automatically updated to reflect the committed changes.
Closed by commit rGbd9e23943a22: [analyzer] Expand conversion check to check
more expressions for overflow and… (authored by martong).
Changed prior to commit:
https://reviews.llvm.org/D46081?vs=144202&id=394502#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D46081/new/
https://reviews.llvm.org/D46081
Files:
clang/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
clang/test/Analysis/conversion.c
clang/test/Analysis/conversion.cpp
Index: clang/test/Analysis/conversion.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/conversion.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang_analyze_cc1 -Wno-conversion -Wno-tautological-constant-compare -analyzer-checker=core,alpha.core.Conversion -verify %s
+
+// expected-no-diagnostics
+
+void dontwarn1() {
+ unsigned long x = static_cast<unsigned long>(-1);
+}
+
+void dontwarn2(unsigned x) {
+ if (x == static_cast<unsigned>(-1)) {
+ }
+}
+
+struct C {
+ C(unsigned x, unsigned long y) {}
+};
+
+void f(C) {}
+
+void functioncall1(long x) {
+ f(C(64, x));
+}
Index: clang/test/Analysis/conversion.c
===================================================================
--- clang/test/Analysis/conversion.c
+++ clang/test/Analysis/conversion.c
@@ -105,6 +105,23 @@
S = U / S; // expected-warning {{Loss of sign}}
}
+void f(unsigned x) {}
+void g(unsigned x) {}
+
+void functioncall1() {
+ long x = -1;
+ int y = 0;
+ f(x); // expected-warning {{Loss of sign in implicit conversion}}
+ f(y);
+}
+
+void functioncall2(int x, int y) {
+ if (x < 0)
+ f(x); // expected-warning {{Loss of sign in implicit conversion}}
+ f(y);
+ f(x); // expected-warning {{Loss of sign in implicit conversion}}
+}
+
void dontwarn1(unsigned U, signed S) {
U8 = S; // It might be known that S is always 0x00-0xff.
S8 = U; // It might be known that U is always 0x00-0xff.
@@ -132,15 +149,38 @@
DOSTUFF;
}
-// don't warn for calculations
-// seen some fp. For instance: c2 = (c2 >= 'A' && c2 <= 'Z') ? c2 - 'A' + 'a' : c2;
-// there is a todo in the checker to handle calculations
void dontwarn5() {
- signed S = -32;
- U8 = S + 10;
+ unsigned char c1 = 'A';
+ c1 = (c1 >= 'A' && c1 <= 'Z') ? c1 - 'A' + 'a' : c1;
+ unsigned char c2 = 0;
+ c2 = (c2 >= 'A' && c2 <= 'Z') ? c2 - 'A' + 'a' : c2;
+ unsigned char c3 = 'Z';
+ c3 = (c3 >= 'A' && c3 <= 'Z') ? c3 - 'A' + 'a' : c3;
+ unsigned char c4 = 'a';
+ c4 = (c4 >= 'A' && c4 <= 'Z') ? c4 - 'A' + 'a' : c4;
+ unsigned char c5 = '@';
+ c5 = (c5 >= 'A' && c5 <= 'Z') ? c5 - 'A' + 'a' : c5;
+}
+
+void dontwarn6() {
+ int x = ~0;
+ unsigned y = ~0;
+}
+
+void dontwarn7(unsigned x) {
+ if (x == (unsigned)-1) {
+ }
+}
+
+void dontwarn8() {
+ unsigned x = (unsigned)-1;
+}
+
+unsigned dontwarn9() {
+ return ~0;
}
-char dontwarn6(long long x) {
+char dontwarn10(long long x) {
long long y = 42;
y += x;
return y == 42;
Index: clang/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
@@ -56,9 +56,8 @@
void ConversionChecker::checkPreStmt(const ImplicitCastExpr *Cast,
CheckerContext &C) const {
- // TODO: For now we only warn about DeclRefExpr, to avoid noise. Warn for
- // calculations also.
- if (!isa<DeclRefExpr>(Cast->IgnoreParenImpCasts()))
+ // Don't warn for implicit conversions to bool
+ if (Cast->getType()->isBooleanType())
return;
// Don't warn for loss of sign/precision in macros.
@@ -70,6 +69,9 @@
const Stmt *Parent = PM.getParent(Cast);
if (!Parent)
return;
+ // Dont warn if this is part of an explicit cast
+ if (isa<ExplicitCastExpr>(Parent))
+ return;
bool LossOfSign = false;
bool LossOfPrecision = false;
@@ -78,8 +80,10 @@
if (const auto *B = dyn_cast<BinaryOperator>(Parent)) {
BinaryOperator::Opcode Opc = B->getOpcode();
if (Opc == BO_Assign) {
- LossOfSign = isLossOfSign(Cast, C);
- LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
+ if (!Cast->IgnoreParenImpCasts()->isEvaluatable(C.getASTContext())) {
+ LossOfSign = isLossOfSign(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
+ }
} else if (Opc == BO_AddAssign || Opc == BO_SubAssign) {
// No loss of sign.
LossOfPrecision = isLossOfPrecision(Cast, B->getLHS()->getType(), C);
@@ -98,7 +102,12 @@
} else if (B->isRelationalOp() || B->isMultiplicativeOp()) {
LossOfSign = isLossOfSign(Cast, C);
}
- } else if (isa<DeclStmt>(Parent)) {
+ } else if (isa<DeclStmt, ReturnStmt>(Parent)) {
+ if (!Cast->IgnoreParenImpCasts()->isEvaluatable(C.getASTContext())) {
+ LossOfSign = isLossOfSign(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
+ }
+ } else {
LossOfSign = isLossOfSign(Cast, C);
LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
}
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