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[Diagnostics] Refactor code for -Wsizeof-pointer-div, catch more cases; also add -Wsizeof-array-div 

Previously, -Wsizeof-pointer-div failed to catch:
const int *r;
sizeof(r) / sizeof(int);

Now fixed.
Also introduced -Wsizeof-array-div which catches bugs like:
sizeof(r) / sizeof(short);

(Array element type does not match type of sizeof operand).

llvm-svn: 371222
This commit is contained in:
David Bolvansky 2019-09-06 16:12:48 +00:00
parent 4f0e429acc
commit fd07568074
4 changed files with 40 additions and 21 deletions
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6
clang/include/clang/Basic/DiagnosticSemaKinds.td
View File

@ -3391,6 +3391,10 @@ def note_pointer_declared_here : Note<
def warn_division_sizeof_ptr : Warning<
"'%0' will return the size of the pointer, not the array itself">,
InGroup<DiagGroup<"sizeof-pointer-div">>;
def warn_division_sizeof_array : Warning<
"expresion will return the incorrect number of elements in the array; the array "
"element type is %0, not %1">,
InGroup<DiagGroup<"sizeof-array-div">>;
def note_function_warning_silence : Note<
"prefix with the address-of operator to silence this warning">;
@ -8003,7 +8007,7 @@ def warn_array_index_precedes_bounds : Warning<
def warn_array_index_exceeds_bounds : Warning<
"array index %0 is past the end of the array (which contains %1 "
"element%s2)">, InGroup<ArrayBounds>;
def note_array_index_out_of_bounds : Note<
def note_array_declared_here : Note<
"array %0 declared here">;
def warn_printf_insufficient_data_args : Warning<

2
clang/lib/Sema/SemaChecking.cpp
View File

@ -13008,7 +13008,7 @@ void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
if (ND)
DiagRuntimeBehavior(ND->getBeginLoc(), BaseExpr,
PDiag(diag::note_array_index_out_of_bounds)
PDiag(diag::note_array_declared_here)
<< ND->getDeclName());
}

35
clang/lib/Sema/SemaExpr.cpp
View File

@ -9135,7 +9135,7 @@ static void checkArithmeticNull(Sema &S, ExprResult &LHS, ExprResult &RHS,
<< LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
}
static void DiagnoseDivisionSizeofPointer(Sema &S, Expr *LHS, Expr *RHS,
static void DiagnoseDivisionSizeofPointerOrArray(Sema &S, Expr *LHS, Expr *RHS,
SourceLocation Loc) {
const auto *LUE = dyn_cast<UnaryExprOrTypeTraitExpr>(LHS);
const auto *RUE = dyn_cast<UnaryExprOrTypeTraitExpr>(RHS);
@ -9154,16 +9154,29 @@ static void DiagnoseDivisionSizeofPointer(Sema &S, Expr *LHS, Expr *RHS,
else
RHSTy = RUE->getArgumentExpr()->IgnoreParens()->getType();
if (!LHSTy->isPointerType() || RHSTy->isPointerType())
return;
if (LHSTy->getPointeeType().getCanonicalType() != RHSTy.getCanonicalType())
return;
if (LHSTy->isPointerType() && !RHSTy->isPointerType()) {
if (LHSTy->getPointeeType().getCanonicalType().getUnqualifiedType() !=
RHSTy.getCanonicalType().getUnqualifiedType())
return;
S.Diag(Loc, diag::warn_division_sizeof_ptr) << LHS << LHS->getSourceRange();
if (const auto *DRE = dyn_cast<DeclRefExpr>(LHSArg)) {
if (const ValueDecl *LHSArgDecl = DRE->getDecl())
S.Diag(LHSArgDecl->getLocation(), diag::note_pointer_declared_here)
<< LHSArgDecl;
S.Diag(Loc, diag::warn_division_sizeof_ptr) << LHS << LHS->getSourceRange();
if (const auto *DRE = dyn_cast<DeclRefExpr>(LHSArg)) {
if (const ValueDecl *LHSArgDecl = DRE->getDecl())
S.Diag(LHSArgDecl->getLocation(), diag::note_pointer_declared_here)
<< LHSArgDecl;
}
} else if (isa<ArrayType>(LHSTy) && !RHSTy->isArrayType()) {
QualType ArrayElemTy = cast<ArrayType>(LHSTy)->getElementType();
if (isa<ArrayType>(ArrayElemTy) ||
ArrayElemTy.getCanonicalType().getUnqualifiedType() ==
RHSTy.getCanonicalType().getUnqualifiedType())
return;
S.Diag(Loc, diag::warn_division_sizeof_array) << ArrayElemTy << RHSTy;
if (const auto *DRE = dyn_cast<DeclRefExpr>(LHSArg)) {
if (const ValueDecl *LHSArgDecl = DRE->getDecl())
S.Diag(LHSArgDecl->getLocation(), diag::note_array_declared_here)
<< LHSArgDecl;
}
}
}
@ -9200,7 +9213,7 @@ QualType Sema::CheckMultiplyDivideOperands(ExprResult &LHS, ExprResult &RHS,
return InvalidOperands(Loc, LHS, RHS);
if (IsDiv) {
DiagnoseBadDivideOrRemainderValues(*this, LHS, RHS, Loc, IsDiv);
DiagnoseDivisionSizeofPointer(*this, LHS.get(), RHS.get(), Loc);
DiagnoseDivisionSizeofPointerOrArray(*this, LHS.get(), RHS.get(), Loc);
}
return compType;
}

18
clang/test/Sema/div-sizeof-ptr.cpp
View File

@ -7,18 +7,20 @@ int f(Ty (&Array)[N]) {
typedef int int32;
void test(int *p, int **q) { // expected-note 5 {{pointer 'p' declared here}}
int a1 = sizeof(p) / sizeof(*p); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a2 = sizeof p / sizeof *p; // expected-warning {{'sizeof p' will return the size of the pointer, not the array itself}}
int a3 = sizeof(p) / sizeof(int); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a4 = sizeof(p) / sizeof(p[0]); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
void test(int *p, int **q) { // expected-note 5 {{pointer 'p' declared here}}
const int *r; // expected-note {{pointer 'r' declared here}}
int a1 = sizeof(p) / sizeof(*p); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a2 = sizeof p / sizeof *p; // expected-warning {{'sizeof p' will return the size of the pointer, not the array itself}}
int a3 = sizeof(p) / sizeof(int); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a4 = sizeof(p) / sizeof(p[0]); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a5 = sizeof(p) / sizeof(int32); // expected-warning {{'sizeof (p)' will return the size of the pointer, not the array itself}}
int a6 = sizeof(r) / sizeof(int); // expected-warning {{'sizeof (r)' will return the size of the pointer, not the array itself}}
int32 *d; // expected-note 2 {{pointer 'd' declared here}}
int a6 = sizeof(d) / sizeof(int32); // expected-warning {{'sizeof (d)' will return the size of the pointer, not the array itself}}
int a7 = sizeof(d) / sizeof(int); // expected-warning {{'sizeof (d)' will return the size of the pointer, not the array itself}}
int a7 = sizeof(d) / sizeof(int32); // expected-warning {{'sizeof (d)' will return the size of the pointer, not the array itself}}
int a8 = sizeof(d) / sizeof(int); // expected-warning {{'sizeof (d)' will return the size of the pointer, not the array itself}}
int a8 = sizeof(*q) / sizeof(**q); // expected-warning {{'sizeof (*q)' will return the size of the pointer, not the array itself}}
int a9 = sizeof(*q) / sizeof(**q); // expected-warning {{'sizeof (*q)' will return the size of the pointer, not the array itself}}
// Should not warn
int b1 = sizeof(int *) / sizeof(int);