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Currently, we infer 0 if the divisible of the modulo op is 0:
int a = x < 0; // a can be 0
int b = a % y; // b is either 1 % sym or 0
However, we don't when the op is / :
int a = x < 0; // a can be 0
int b = a / y; // b is either 1 / sym or 0 / sym
This commit fixes the discrepancy.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D99343
Files:
clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
clang/test/Analysis/zero-operands.c
Index: clang/test/Analysis/zero-operands.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/zero-operands.c
@@ -0,0 +1,53 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core \
+// RUN: -analyzer-checker=debug.ExprInspection \
+// RUN: -verify %s
+
+void clang_analyzer_dump(int);
+
+void test_0_multiplier1(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a * y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{reg_${{[[:digit:]]+}}<int y>}}
+}
+
+void test_0_multiplier2(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = y * a;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{reg_${{[[:digit:]]+}}<int y>}}
+}
+
+void test_0_modulo(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a % y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{1 % (reg_${{[[:digit:]]+}}<int y>)}}
+}
+
+void test_0_divisible(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a / y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{1 / (reg_${{[[:digit:]]+}}<int y>)}}
+}
Index: clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -652,6 +652,7 @@
if (LHSValue == 0)
return evalCastFromNonLoc(lhs, resultTy);
return makeSymExprValNN(op, InputLHS, InputRHS, resultTy);
+ case BO_Div:
case BO_Rem:
// 0 % x == 0
if (LHSValue == 0)
Index: clang/test/Analysis/zero-operands.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/zero-operands.c
@@ -0,0 +1,53 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core \
+// RUN: -analyzer-checker=debug.ExprInspection \
+// RUN: -verify %s
+
+void clang_analyzer_dump(int);
+
+void test_0_multiplier1(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a * y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{reg_${{[[:digit:]]+}}<int y>}}
+}
+
+void test_0_multiplier2(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = y * a;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{reg_${{[[:digit:]]+}}<int y>}}
+}
+
+void test_0_modulo(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a % y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{1 % (reg_${{[[:digit:]]+}}<int y>)}}
+}
+
+void test_0_divisible(int x, int y) {
+ int a = x < 0; // Eagerly bifurcate.
+ clang_analyzer_dump(a);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning@-2{{1 S32b}}
+
+ int b = a / y;
+ clang_analyzer_dump(b);
+ // expected-warning@-1{{0 S32b}}
+ // expected-warning-re@-2{{1 / (reg_${{[[:digit:]]+}}<int y>)}}
+}
Index: clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -652,6 +652,7 @@
if (LHSValue == 0)
return evalCastFromNonLoc(lhs, resultTy);
return makeSymExprValNN(op, InputLHS, InputRHS, resultTy);
+ case BO_Div:
case BO_Rem:
// 0 % x == 0
if (LHSValue == 0)
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