jamieschmeiser updated this revision to Diff 336567.
jamieschmeiser added a comment.
Respond to review comments: Do not issue warning for nullptr - nullptr in C++.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D98798/new/
https://reviews.llvm.org/D98798
Files:
clang/lib/Sema/SemaExpr.cpp
clang/test/Sema/pointer-addition.c
Index: clang/test/Sema/pointer-addition.c
===================================================================
--- clang/test/Sema/pointer-addition.c
+++ clang/test/Sema/pointer-addition.c
@@ -29,4 +29,7 @@
// Cases that don't match the GNU inttoptr idiom get a different warning.
f = (char*)0 - i; // expected-warning {{performing pointer arithmetic on a
null pointer has undefined behavior}}
int *g = (int*)0 + i; // expected-warning {{performing pointer arithmetic on
a null pointer has undefined behavior}}
+ f = (char*)((char*)0 - f); // expected-warning {{performing pointer
arithmetic on a null pointer has undefined behavior}}
+ f = (char*)(f - (char*)0); // expected-warning {{performing pointer
arithmetic on a null pointer has undefined behavior}}
+ f = (char*)((char*)0 - (char*)0); // expected-warning {{performing pointer
arithmetic on a null pointer has undefined behavior}} expected-warning
{{performing pointer arithmetic on a null pointer has undefined behavior}}
}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -10720,7 +10720,17 @@
LHS.get(), RHS.get()))
return QualType();
- // FIXME: Add warnings for nullptr - ptr.
+ bool LHSIsNullPtr = LHS.get()->IgnoreParenCasts()->isNullPointerConstant(
+ Context, Expr::NPC_ValueDependentIsNotNull);
+ bool RHSIsNullPtr = RHS.get()->IgnoreParenCasts()->isNullPointerConstant(
+ Context, Expr::NPC_ValueDependentIsNotNull);
+
+ // Subtracting nullptr or from nullptr should produce
+ // a warning expect nullptr - nullptr is valid in C++ [expr.add]p7
+ if (LHSIsNullPtr && (!getLangOpts().CPlusPlus || !RHSIsNullPtr))
+ diagnoseArithmeticOnNullPointer(*this, Loc, LHS.get(), false);
+ if (RHSIsNullPtr && (!getLangOpts().CPlusPlus || !LHSIsNullPtr))
+ diagnoseArithmeticOnNullPointer(*this, Loc, RHS.get(), false);
// The pointee type may have zero size. As an extension, a structure or
// union may have zero size or an array may have zero length. In this
Index: clang/test/Sema/pointer-addition.c
===================================================================
--- clang/test/Sema/pointer-addition.c
+++ clang/test/Sema/pointer-addition.c
@@ -29,4 +29,7 @@
// Cases that don't match the GNU inttoptr idiom get a different warning.
f = (char*)0 - i; // expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}}
int *g = (int*)0 + i; // expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}}
+ f = (char*)((char*)0 - f); // expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}}
+ f = (char*)(f - (char*)0); // expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}}
+ f = (char*)((char*)0 - (char*)0); // expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}} expected-warning {{performing pointer arithmetic on a null pointer has undefined behavior}}
}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -10720,7 +10720,17 @@
LHS.get(), RHS.get()))
return QualType();
- // FIXME: Add warnings for nullptr - ptr.
+ bool LHSIsNullPtr = LHS.get()->IgnoreParenCasts()->isNullPointerConstant(
+ Context, Expr::NPC_ValueDependentIsNotNull);
+ bool RHSIsNullPtr = RHS.get()->IgnoreParenCasts()->isNullPointerConstant(
+ Context, Expr::NPC_ValueDependentIsNotNull);
+
+ // Subtracting nullptr or from nullptr should produce
+ // a warning expect nullptr - nullptr is valid in C++ [expr.add]p7
+ if (LHSIsNullPtr && (!getLangOpts().CPlusPlus || !RHSIsNullPtr))
+ diagnoseArithmeticOnNullPointer(*this, Loc, LHS.get(), false);
+ if (RHSIsNullPtr && (!getLangOpts().CPlusPlus || !LHSIsNullPtr))
+ diagnoseArithmeticOnNullPointer(*this, Loc, RHS.get(), false);
// The pointee type may have zero size. As an extension, a structure or
// union may have zero size or an array may have zero length. In this
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