MTC created this revision.
MTC added reviewers: alexshap, NoQ, dcoughlin.
Herald added subscribers: cfe-commits, a.sidorin, szepet, xazax.hun.
Herald added a reviewer: george.karpenkov.
There is a problem with analyzer that a wrong value is given when modeling the
increment operator of the operand with type bool. After `rL307604` is applied,
a unsigned overflow may occur.
Example:
void func() {
bool b = true;
// unsigned overflow occur, 2 -> 0 U1b
b++;
}
The use of an operand of type bool with the ++ operators is deprecated but
valid untill C++17. And if the operand of the increment operator is of type
bool, it is set to true.
This patch includes two parts:
- If the operand of the increment operator is of type bool, set to true.
- Modify `BasicValueFactory::getTruthValue()`, use `getIntWidth()` instead
`getTypeSize()` and use `unsigned` instead `signed`.
Repository:
rC Clang
https://reviews.llvm.org/D43741
Files:
include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
lib/StaticAnalyzer/Core/ExprEngineC.cpp
test/Analysis/bool.cpp
Index: test/Analysis/bool.cpp
===================================================================
--- /dev/null
+++ test/Analysis/bool.cpp
@@ -0,0 +1,84 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection -analyzer-store=region -verify -std=c++11 -Wno-deprecated %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection -analyzer-store=region -verify -std=c++14 -Wno-deprecated %s
+
+extern void clang_analyzer_eval(bool);
+extern void clang_analyzer_dump(bool);
+
+void test_bool_increment() {
+ {
+ bool b = true;
+ b++;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = false;
+ b++;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = true;
+ ++b;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = false;
+ ++b;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = 0;
+ ++b;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = 10;
+ ++b;
+ ++b;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+
+ {
+ bool b = -10;
+ ++b;
+ clang_analyzer_eval(b); // expected-warning{{TRUE}}
+ }
+}
+
+void test_bool_value() {
+ {
+ bool b = true;
+ clang_analyzer_dump(b); // expected-warning{{1 U1b}}
+ }
+
+ {
+ bool b = false;
+ clang_analyzer_dump(b); // expected-warning{{0 U1b}}
+ }
+
+ {
+ bool b = -10;
+ clang_analyzer_dump(b); // expected-warning{{1 U1b}}
+ }
+
+ {
+ bool b = 10;
+ clang_analyzer_dump(b); // expected-warning{{1 U1b}}
+ }
+
+ {
+ bool b = 10;
+ b++;
+ clang_analyzer_dump(b); // expected-warning{{1 U1b}}
+ }
+
+ {
+ bool b = 0;
+ b++;
+ clang_analyzer_dump(b); // expected-warning{{1 U1b}}
+ }
+}
Index: lib/StaticAnalyzer/Core/ExprEngineC.cpp
===================================================================
--- lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -1066,15 +1066,23 @@
// constant value. If the UnaryOperator has location type, create the
// constant with int type and pointer width.
SVal RHS;
+ SVal Result;
if (U->getType()->isAnyPointerType())
RHS = svalBuilder.makeArrayIndex(1);
else if (U->getType()->isIntegralOrEnumerationType())
RHS = svalBuilder.makeIntVal(1, U->getType());
else
RHS = UnknownVal();
- SVal Result = evalBinOp(state, Op, V2, RHS, U->getType());
+ // The use of an operand of type bool with the ++ operators is deprecated
+ // but valid untill C++17. And if the operand of the increment operator is
+ // of type bool, it is set to true untill C++17.
+ if (U->getType()->isBooleanType() && U->isIncrementOp() &&
+ AMgr.getLangOpts().CPlusPlus)
+ Result = svalBuilder.makeTruthVal(true, U->getType());
+ else
+ Result = evalBinOp(state, Op, V2, RHS, U->getType());
// Conjure a new symbol if necessary to recover precision.
if (Result.isUnknown()){
@@ -1096,7 +1104,6 @@
Constraint = svalBuilder.evalEQ(state, SymVal,
svalBuilder.makeZeroVal(U->getType()));
-
state = state->assume(Constraint, false);
assert(state);
}
Index: include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
@@ -194,7 +194,7 @@
}
inline const llvm::APSInt& getTruthValue(bool b, QualType T) {
- return getValue(b ? 1 : 0, Ctx.getTypeSize(T), false);
+ return getValue(b ? 1 : 0, Ctx.getIntWidth(T), true);
}
inline const llvm::APSInt& getTruthValue(bool b) {
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