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Previously `LValueToRValueBitCast`s were modeled in the same way how
a regular `BitCast` was. However, this should not produce an l-value.
Modeling bitcasts accurately is tricky, so it's probably better to
model this expression by binding a fresh conjured value.
The following code should not result in a diagnostic:
__attribute__((always_inline))
static inline constexpr unsigned int_castf32_u32(float __A) {
return __builtin_bit_cast(unsigned int, __A); // no-warning
}
Previously, it reported
`Address of stack memory associated with local variable '__A' returned to
caller [core.StackAddressEscape]`.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D105017
Files:
clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
clang/test/Analysis/builtin_bitcast.cpp
Index: clang/test/Analysis/builtin_bitcast.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/builtin_bitcast.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_analyze_cc1 -verify %s \
+// RUN: -analyzer-checker=core,debug.ExprInspection
+
+template <typename T> void clang_analyzer_dump(T);
+
+__attribute__((always_inline)) static inline constexpr unsigned int
_castf32_u32(float __A) {
+ return __builtin_bit_cast(unsigned int, __A); // no-warning
+}
+
+void test() {
+ _castf32_u32(42);
+
+ float f = 42;
+ unsigned int g = __builtin_bit_cast(unsigned int, f);
+ clang_analyzer_dump(g);
+ // expected-warning-re@-1{{{{^conj_\$[0-9]+{unsigned int, LC[0-9]+, S[0-9]+,
#[0-9]+}}}}}
+}
Index: clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -380,7 +380,6 @@
case CK_Dependent:
case CK_ArrayToPointerDecay:
case CK_BitCast:
- case CK_LValueToRValueBitCast:
case CK_AddressSpaceConversion:
case CK_BooleanToSignedIntegral:
case CK_IntegralToPointer:
@@ -538,6 +537,7 @@
continue;
}
// Various C++ casts that are not handled yet.
+ case CK_LValueToRValueBitCast:
case CK_ToUnion:
case CK_VectorSplat: {
state = handleLVectorSplat(state, LCtx, CastE, Bldr, Pred);
Index: clang/test/Analysis/builtin_bitcast.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/builtin_bitcast.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_analyze_cc1 -verify %s \
+// RUN: -analyzer-checker=core,debug.ExprInspection
+
+template <typename T> void clang_analyzer_dump(T);
+
+__attribute__((always_inline)) static inline constexpr unsigned int _castf32_u32(float __A) {
+ return __builtin_bit_cast(unsigned int, __A); // no-warning
+}
+
+void test() {
+ _castf32_u32(42);
+
+ float f = 42;
+ unsigned int g = __builtin_bit_cast(unsigned int, f);
+ clang_analyzer_dump(g);
+ // expected-warning-re@-1{{{{^conj_\$[0-9]+{unsigned int, LC[0-9]+, S[0-9]+, #[0-9]+}}}}}
+}
Index: clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -380,7 +380,6 @@
case CK_Dependent:
case CK_ArrayToPointerDecay:
case CK_BitCast:
- case CK_LValueToRValueBitCast:
case CK_AddressSpaceConversion:
case CK_BooleanToSignedIntegral:
case CK_IntegralToPointer:
@@ -538,6 +537,7 @@
continue;
}
// Various C++ casts that are not handled yet.
+ case CK_LValueToRValueBitCast:
case CK_ToUnion:
case CK_VectorSplat: {
state = handleLVectorSplat(state, LCtx, CastE, Bldr, Pred);
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