arichardson created this revision.
arichardson added reviewers: courbet, Quuxplusone, aaron.ballman.
arichardson requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Trying to debug a static_assert(sizeof(foo) == ...) failure can be rather
awkward since there is no easy way to print the value of the sizeof() at
compile-time without another compiler diagnostic involving an array size.
This patch emits additional notes when a static_assert fails for any
UnaryExprOrTypeTraitExpr expression inside the static_assert.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D108211
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaDeclCXX.cpp
clang/lib/Sema/SemaTemplate.cpp
clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
clang/test/Parser/objc-static-assert.mm
clang/test/Sema/static-assert.c
clang/test/SemaCXX/constant-expression-cxx11.cpp
clang/test/SemaCXX/static-assert-cxx17.cpp
clang/test/SemaCXX/static-assert.cpp
clang/test/SemaTemplate/overload-candidates.cpp
Index: clang/test/SemaTemplate/overload-candidates.cpp
===================================================================
--- clang/test/SemaTemplate/overload-candidates.cpp
+++ clang/test/SemaTemplate/overload-candidates.cpp
@@ -62,6 +62,7 @@
template<typename T> struct NonTemplateFunction {
typename boost::enable_if<sizeof(T) == 4, int>::type f(); // expected-error{{failed requirement 'sizeof(char) == 4'; 'enable_if' cannot be used to disable this declaration}}
+ // expected-note@-1{{with 'sizeof(char)' equal to 1}}
};
NonTemplateFunction<char> NTFC; // expected-note{{here}}
Index: clang/test/SemaCXX/static-assert.cpp
===================================================================
--- clang/test/SemaCXX/static-assert.cpp
+++ clang/test/SemaCXX/static-assert.cpp
@@ -21,8 +21,10 @@
T<1> t1; // expected-note {{in instantiation of template class 'T<1>' requested here}}
T<2> t2;
-template<typename T> struct S {
- static_assert(sizeof(T) > sizeof(char), "Type not big enough!"); // expected-error {{static_assert failed due to requirement 'sizeof(char) > sizeof(char)' "Type not big enough!"}}
+template <typename T> struct S {
+ static_assert(sizeof(T) > sizeof(char), "Type not big enough!"); // expected-error {{static_assert failed due to requirement 'sizeof(char) > sizeof(char)' "Type not big enough!"}}
+ // expected-note@-1{{with 'sizeof(char)' equal to 1}}
+ // expected-note@-2{{with 'sizeof(char)' equal to 1}}
};
S<char> s1; // expected-note {{in instantiation of template class 'S<char>' requested here}}
@@ -199,3 +201,18 @@
constexpr NotBool constexprNotBool;
static_assert(notBool, "message"); // expected-error {{value of type 'struct NotBool' is not contextually convertible to 'bool'}}
static_assert(constexprNotBool, "message"); // expected-error {{value of type 'const NotBool' is not contextually convertible to 'bool'}}
+
+struct IntAndPointer {
+ int i;
+ void *p;
+};
+static_assert(sizeof(IntAndPointer) == 4, "message");
+// expected-error@-1{{static_assert failed due to requirement 'sizeof(IntAndPointer) == 4' "message"}}
+// expected-note@-2{{with 'sizeof(IntAndPointer)' equal to 16}}
+static_assert(alignof(IntAndPointer) == 4, "message");
+// expected-error@-1{{static_assert failed due to requirement 'alignof(IntAndPointer) == 4' "message"}}
+// expected-note@-2{{with 'alignof(IntAndPointer)' equal to 8}}
+static_assert(alignof(IntAndPointer) == sizeof(IntAndPointer), "message");
+// expected-error@-1{{static_assert failed due to requirement 'alignof(IntAndPointer) == sizeof(IntAndPointer)' "message"}}
+// expected-note@-2{{with 'alignof(IntAndPointer)' equal to 8}}
+// expected-note@-3{{with 'sizeof(IntAndPointer)' equal to 16}}
Index: clang/test/SemaCXX/static-assert-cxx17.cpp
===================================================================
--- clang/test/SemaCXX/static-assert-cxx17.cpp
+++ clang/test/SemaCXX/static-assert-cxx17.cpp
@@ -89,6 +89,7 @@
// expected-error@-1{{static_assert failed due to requirement 'int(0)'}}
static_assert(sizeof(X<typename T::T>) == 0);
// expected-error@-1{{static_assert failed due to requirement 'sizeof(X<int>) == 0'}}
+ // expected-note@-2{{with 'sizeof(X<int>)' equal to 8}}
static_assert((const X<typename T::T> *)nullptr);
// expected-error@-1{{static_assert failed due to requirement '(const X<int> *)nullptr'}}
static_assert(static_cast<const X<typename T::T> *>(nullptr));
@@ -97,6 +98,7 @@
// expected-error@-1{{static_assert failed due to requirement '(X<int> const[0]){} == nullptr'}}
static_assert(sizeof(X<decltype(X<typename T::T>().X<typename T::T>::~X())>) == 0);
// expected-error@-1{{static_assert failed due to requirement 'sizeof(X<void>) == 0'}}
+ // expected-note@-2{{with 'sizeof(X<void>)' equal to 8}}
static_assert(constexpr_return_false<typename T::T, typename T::U>());
// expected-error@-1{{static_assert failed due to requirement 'constexpr_return_false<int, float>()'}}
}
Index: clang/test/SemaCXX/constant-expression-cxx11.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -1908,11 +1908,13 @@
// cxx11-error@-1 {{not an integral constant expression}}
// cxx11-note@-2 {{call to virtual function}}
// cxx20_2b-error@-3 {{static_assert failed}}
+ // cxx20_2b-note@-4 {{with 'sizeof(VirtualFromBase::X<VirtualFromBase::S1>)' equal to 16}}
// Non-virtual f(), OK.
constexpr X<X<S2>> xxs2;
constexpr X<S2> *q = const_cast<X<X<S2>>*>(&xxs2);
static_assert(q->f() == sizeof(S2), ""); // cxx20_2b-error {{static_assert failed}}
+ // cxx20_2b-note@-1 {{with 'sizeof(VirtualFromBase::S2)' equal to 8}}
}
namespace ConstexprConstructorRecovery {
Index: clang/test/Sema/static-assert.c
===================================================================
--- clang/test/Sema/static-assert.c
+++ clang/test/Sema/static-assert.c
@@ -55,7 +55,9 @@
typedef UNION(unsigned, struct A) U1; // ext-warning 3 {{'_Static_assert' is a C11 extension}}
UNION(char[2], short) u2 = { .one = { 'a', 'b' } }; // ext-warning 3 {{'_Static_assert' is a C11 extension}} cxx-warning {{designated initializers are a C++20 extension}}
typedef UNION(char, short) U3; // expected-error {{static_assert failed due to requirement 'sizeof(char) == sizeof(short)' "type size mismatch"}} \
- // ext-warning 3 {{'_Static_assert' is a C11 extension}}
+ // ext-warning 3 {{'_Static_assert' is a C11 extension}} \
+ // expected-note {{with 'sizeof(char)' equal to 1}} \
+ // expected-note {{with 'sizeof(short)' equal to 2}}
typedef UNION(float, 0.5f) U4; // expected-error {{expected a type}} \
// ext-warning 3 {{'_Static_assert' is a C11 extension}}
Index: clang/test/Parser/objc-static-assert.mm
===================================================================
--- clang/test/Parser/objc-static-assert.mm
+++ clang/test/Parser/objc-static-assert.mm
@@ -26,7 +26,7 @@
static_assert(a, ""); // expected-error {{static_assert expression is not an integral constant expression}}
static_assert(sizeof(a) == 4, "");
- static_assert(sizeof(a) == 3, ""); // expected-error {{static_assert failed}}
+ static_assert(sizeof(a) == 3, ""); // expected-error {{static_assert failed}} expected-note{{with 'sizeof (a)' equal to 4}}
}
static_assert(1, "");
@@ -40,7 +40,7 @@
static_assert(1, "");
_Static_assert(1, "");
static_assert(sizeof(b) == 4, "");
- static_assert(sizeof(b) == 3, ""); // expected-error {{static_assert failed}}
+ static_assert(sizeof(b) == 3, ""); // expected-error {{static_assert failed}} expected-note{{with 'sizeof (b)' equal to 4}}
}
static_assert(1, "");
@@ -56,7 +56,7 @@
@interface B () {
int b;
static_assert(sizeof(b) == 4, "");
- static_assert(sizeof(b) == 3, ""); // expected-error {{static_assert failed}}
+ static_assert(sizeof(b) == 3, ""); // expected-error {{static_assert failed}} expected-note{{with 'sizeof (b)' equal to 4}}
}
@end
Index: clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
===================================================================
--- clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
+++ clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
@@ -98,7 +98,7 @@
static_assert(sizeof(arr2) == 12, "");
// Use a failing test to ensure the type isn't considered dependent.
- static_assert(sizeof(arr2) == 13, ""); // expected-error {{failed}}
+ static_assert(sizeof(arr2) == 13, ""); // expected-error {{failed}} expected-note{{with 'sizeof (arr2)' equal to 12}}
}
void g() { f<int[3]>(); } // expected-note {{in instantiation of}}
Index: clang/lib/Sema/SemaTemplate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplate.cpp
+++ clang/lib/Sema/SemaTemplate.cpp
@@ -3574,8 +3574,10 @@
// for actual types.
class FailedBooleanConditionPrinterHelper : public PrinterHelper {
public:
- explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
- : Policy(P) {}
+ explicit FailedBooleanConditionPrinterHelper(
+ const PrintingPolicy &P, Sema &S,
+ SmallVectorImpl<PartialDiagnosticAt> &Notes)
+ : Policy(P), S(S), Notes(Notes) {}
bool handledStmt(Stmt *E, raw_ostream &OS) override {
const auto *DR = dyn_cast<DeclRefExpr>(E);
@@ -3593,18 +3595,34 @@
IV->getSpecializedTemplate()->getTemplateParameters());
}
return true;
+ } else if (auto *UE = dyn_cast<UnaryExprOrTypeTraitExpr>(E)) {
+ Expr::EvalResult Result;
+ if (UE->EvaluateAsConstantExpr(Result, S.Context) && Result.Val.isInt()) {
+ std::string ExprStr;
+ llvm::raw_string_ostream ExprStream(ExprStr);
+ UE->printPretty(ExprStream, nullptr, Policy);
+ ExprStream.flush();
+ Notes.push_back(PartialDiagnosticAt(
+ UE->getExprLoc(),
+ S.PDiag(diag::note_static_assert_requirement_context)
+ << ExprStr << toString(Result.Val.getInt(), 10)
+ << UE->getSourceRange()));
+ }
}
return false;
}
private:
const PrintingPolicy Policy;
+ Sema &S;
+ SmallVectorImpl<PartialDiagnosticAt> &Notes;
};
} // end anonymous namespace
std::pair<Expr *, std::string>
-Sema::findFailedBooleanCondition(Expr *Cond) {
+Sema::findFailedBooleanCondition(Expr *Cond,
+ SmallVectorImpl<PartialDiagnosticAt> &Notes) {
Cond = lookThroughRangesV3Condition(PP, Cond);
// Separate out all of the terms in a conjunction.
@@ -3641,7 +3659,7 @@
llvm::raw_string_ostream Out(Description);
PrintingPolicy Policy = getPrintingPolicy();
Policy.PrintCanonicalTypes = true;
- FailedBooleanConditionPrinterHelper Helper(Policy);
+ FailedBooleanConditionPrinterHelper Helper(Policy, *this, Notes);
FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
}
return { FailedCond, Description };
@@ -3729,8 +3747,10 @@
== TemplateArgument::Expression) {
Expr *FailedCond;
std::string FailedDescription;
+ SmallVector<PartialDiagnosticAt, 2> Notes;
std::tie(FailedCond, FailedDescription) =
- findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
+ findFailedBooleanCondition(
+ TemplateArgs[0].getSourceExpression(), Notes);
// Remove the old SFINAE diagnostic.
PartialDiagnosticAt OldDiag =
@@ -3744,6 +3764,8 @@
PDiag(diag::err_typename_nested_not_found_requirement)
<< FailedDescription
<< FailedCond->getSourceRange());
+ for (const PartialDiagnosticAt &Note : Notes)
+ (*DeductionInfo)->addSFINAEDiagnostic(Note.first, Note.second);
}
}
}
@@ -10608,13 +10630,16 @@
if (Cond) {
Expr *FailedCond;
std::string FailedDescription;
+ SmallVector<PartialDiagnosticAt, 2> Notes;
std::tie(FailedCond, FailedDescription) =
- findFailedBooleanCondition(Cond);
+ findFailedBooleanCondition(Cond, Notes);
Diag(FailedCond->getExprLoc(),
diag::err_typename_nested_not_found_requirement)
<< FailedDescription
<< FailedCond->getSourceRange();
+ for (const PartialDiagnosticAt &Note : Notes)
+ Diag(Note.first, Note.second);
return QualType();
}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -16366,8 +16366,9 @@
Expr *InnerCond = nullptr;
std::string InnerCondDescription;
+ SmallVector<PartialDiagnosticAt, 2> Notes;
std::tie(InnerCond, InnerCondDescription) =
- findFailedBooleanCondition(Converted.get());
+ findFailedBooleanCondition(Converted.get(), Notes);
if (InnerCond && isa<ConceptSpecializationExpr>(InnerCond)) {
// Drill down into concept specialization expressions to see why they
// weren't satisfied.
@@ -16385,6 +16386,8 @@
Diag(StaticAssertLoc, diag::err_static_assert_failed)
<< !AssertMessage << Msg.str() << AssertExpr->getSourceRange();
}
+ for (const PartialDiagnosticAt &Note : Notes)
+ Diag(Note.first, Note.second);
Failed = true;
}
} else {
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -3739,7 +3739,9 @@
/// Find the failed Boolean condition within a given Boolean
/// constant expression, and describe it with a string.
- std::pair<Expr *, std::string> findFailedBooleanCondition(Expr *Cond);
+ std::pair<Expr *, std::string>
+ findFailedBooleanCondition(Expr *Cond,
+ SmallVectorImpl<PartialDiagnosticAt> &Notes);
/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// non-ArgDependent DiagnoseIfAttrs.
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1501,6 +1501,7 @@
def err_static_assert_failed : Error<"static_assert failed%select{ %1|}0">;
def err_static_assert_requirement_failed : Error<
"static_assert failed due to requirement '%0'%select{ %2|}1">;
+def note_static_assert_requirement_context : Note<"with '%0' equal to %1">;
def ext_inline_variable : ExtWarn<
"inline variables are a C++17 extension">, InGroup<CXX17>;
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