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Without this patch, clang will not wrap in an ElaboratedType node types written without a keyword and nested name qualifier, which goes against the intent that we should produce an AST which retains enough details to recover how things are written. The lack of this sugar is incompatible with the intent of the type printer default policy, which is to print types as written, but to fall back and print them fully qualified when they are desugared. An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still requires pointer alignment due to pre-existing bug in the TypeLoc buffer handling. --- Troubleshooting list to deal with any breakage seen with this patch: 1) The most likely effect one would see by this patch is a change in how a type is printed. The type printer will, by design and default, print types as written. There are customization options there, but not that many, and they mainly apply to how to print a type that we somehow failed to track how it was written. This patch fixes a problem where we failed to distinguish between a type that was written without any elaborated-type qualifiers, such as a 'struct'/'class' tags and name spacifiers such as 'std::', and one that has been stripped of any 'metadata' that identifies such, the so called canonical types. Example: ``` namespace foo { struct A {}; A a; }; ``` If one were to print the type of `foo::a`, prior to this patch, this would result in `foo::A`. This is how the type printer would have, by default, printed the canonical type of A as well. As soon as you add any name qualifiers to A, the type printer would suddenly start accurately printing the type as written. This patch will make it print it accurately even when written without qualifiers, so we will just print `A` for the initial example, as the user did not really write that `foo::` namespace qualifier. 2) This patch could expose a bug in some AST matcher. Matching types is harder to get right when there is sugar involved. For example, if you want to match a type against being a pointer to some type A, then you have to account for getting a type that is sugar for a pointer to A, or being a pointer to sugar to A, or both! Usually you would get the second part wrong, and this would work for a very simple test where you don't use any name qualifiers, but you would discover is broken when you do. The usual fix is to either use the matcher which strips sugar, which is annoying to use as for example if you match an N level pointer, you have to put N+1 such matchers in there, beginning to end and between all those levels. But in a lot of cases, if the property you want to match is present in the canonical type, it's easier and faster to just match on that... This goes with what is said in 1), if you want to match against the name of a type, and you want the name string to be something stable, perhaps matching on the name of the canonical type is the better choice. 3) This patch could expose a bug in how you get the source range of some TypeLoc. For some reason, a lot of code is using getLocalSourceRange(), which only looks at the given TypeLoc node. This patch introduces a new, and more common TypeLoc node which contains no source locations on itself. This is not an inovation here, and some other, more rare TypeLoc nodes could also have this property, but if you use getLocalSourceRange on them, it's not going to return any valid locations, because it doesn't have any. The right fix here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive into the inner TypeLoc to get the source range if it doesn't find it on the top level one. You can use getLocalSourceRange if you are really into micro-optimizations and you have some outside knowledge that the TypeLocs you are dealing with will always include some source location. 4) Exposed a bug somewhere in the use of the normal clang type class API, where you have some type, you want to see if that type is some particular kind, you try a `dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match. Again, like 2), this would usually have been tested poorly with some simple tests with no qualifications, and would have been broken had there been any other kind of type sugar, be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType. The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper into the type. Or use `getAsAdjusted` when dealing with TypeLocs. For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast. 5) It could be a bug in this patch perhaps. Let me know if you need any help! Signed-off-by: Matheus Izvekov <mizvekov@gmail.com> Differential Revision: https://reviews.llvm.org/D112374
290 lines
6.7 KiB
C++
290 lines
6.7 KiB
C++
// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify %s
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// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify -std=c++98 %s
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// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify -std=c++11 %s
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struct A; // expected-note 4 {{forward declaration of 'A'}}
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struct Abstract { virtual void f() = 0; }; // expected-note {{unimplemented pure virtual method 'f'}}
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void trys() {
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int k = 42;
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try {
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} catch(int i) { // expected-note {{previous definition}}
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int j = i;
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int i; // expected-error {{redefinition of 'i'}}
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} catch(float i) {
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} catch(void v) { // expected-error {{cannot catch incomplete type 'void'}}
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} catch(A a) { // expected-error {{cannot catch incomplete type 'A'}}
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} catch(A *a) { // expected-error {{cannot catch pointer to incomplete type 'A'}}
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} catch(A &a) { // expected-error {{cannot catch reference to incomplete type 'A'}}
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} catch(Abstract) { // expected-error {{variable type 'Abstract' is an abstract class}}
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} catch(...) {
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int ref = k;
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{
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int ref = k;
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}
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int j = i; // expected-error {{use of undeclared identifier 'i'}}
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}
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try {
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} catch(...) { // expected-error {{catch-all handler must come last}}
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} catch(int) {
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}
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}
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void throws() {
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throw;
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throw 0;
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throw throw; // expected-error {{cannot throw object of incomplete type 'void'}}
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throw (A*)0; // expected-error {{cannot throw pointer to object of incomplete type 'A'}}
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}
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void jumps() {
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l1:
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goto l5;
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goto l4; // expected-error {{cannot jump}}
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goto l3; // expected-error {{cannot jump}}
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goto l2; // expected-error {{cannot jump}}
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goto l1;
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try { // expected-note 4 {{jump bypasses initialization of try block}}
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l2:
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goto l5;
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goto l4; // expected-error {{cannot jump}}
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goto l3; // expected-error {{cannot jump}}
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goto l2;
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goto l1;
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} catch(int) { // expected-note 4 {{jump bypasses initialization of catch block}}
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l3:
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goto l5;
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goto l4; // expected-error {{cannot jump}}
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goto l3;
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goto l2; // expected-error {{cannot jump}}
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goto l1;
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} catch(...) { // expected-note 4 {{jump bypasses initialization of catch block}}
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l4:
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goto l5;
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goto l4;
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goto l3; // expected-error {{cannot jump}}
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goto l2; // expected-error {{cannot jump}}
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goto l1;
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}
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l5:
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goto l5;
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goto l4; // expected-error {{cannot jump}}
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goto l3; // expected-error {{cannot jump}}
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goto l2; // expected-error {{cannot jump}}
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goto l1;
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}
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struct BadReturn {
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BadReturn() try {
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} catch(...) {
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// Try to hide
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try {
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} catch(...) {
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{
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if (0)
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return; // expected-error {{return in the catch of a function try block of a constructor is illegal}}
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}
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}
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}
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BadReturn(int);
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};
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BadReturn::BadReturn(int) try {
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} catch(...) {
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// Try to hide
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try {
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} catch(int) {
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return; // expected-error {{return in the catch of a function try block of a constructor is illegal}}
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} catch(...) {
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{
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if (0)
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return; // expected-error {{return in the catch of a function try block of a constructor is illegal}}
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}
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}
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}
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// Cannot throw an abstract type.
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class foo {
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public:
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foo() {}
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void bar () {
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throw *this; // expected-error{{cannot throw an object of abstract type 'foo'}}
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}
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virtual void test () = 0; // expected-note{{unimplemented pure virtual method 'test'}}
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};
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namespace PR6831 {
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namespace NA { struct S; }
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namespace NB { struct S; }
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void f() {
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using namespace NA;
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using namespace NB;
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try {
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} catch (int S) {
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}
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}
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}
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namespace Decay {
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struct A {
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void f() throw (A[10]);
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};
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template<typename T> struct B {
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void f() throw (B[10]);
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};
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template struct B<int>;
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void f() throw (int[10], int(*)());
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void f() throw (int*, int());
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template<typename T> struct C {
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void f() throw (T);
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#if __cplusplus <= 199711L
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// expected-error@-2 {{pointer to incomplete type 'Decay::E' is not allowed in exception specification}}
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#endif
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};
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struct D {
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C<D[10]> c;
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};
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struct E;
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#if __cplusplus <= 199711L
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// expected-note@-2 {{forward declaration of 'Decay::E'}}
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#endif
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C<E[10]> e;
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#if __cplusplus <= 199711L
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// expected-note@-2 {{in instantiation of template class 'Decay::C<Decay::E[10]>' requested here}}
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#endif
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}
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void rval_ref() throw (int &&); // expected-error {{rvalue reference type 'int &&' is not allowed in exception specification}}
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#if __cplusplus <= 199711L
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// expected-warning@-2 {{rvalue references are a C++11 extension}}
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#endif
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namespace HandlerInversion {
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struct B {};
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struct D : B {};
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struct D2 : D {};
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void f1() {
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try {
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} catch (B &b) { // expected-note {{for type 'B &'}}
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} catch (D &d) { // expected-warning {{exception of type 'D &' will be caught by earlier handler}}
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}
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}
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void f2() {
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try {
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} catch (B *b) { // expected-note {{for type 'B *'}}
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} catch (D *d) { // expected-warning {{exception of type 'D *' will be caught by earlier handler}}
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}
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}
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void f3() {
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try {
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} catch (D &d) { // Ok
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} catch (B &b) {
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}
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}
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void f4() {
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try {
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} catch (B &b) { // Ok
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}
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}
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void f5() {
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try {
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} catch (int) {
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} catch (float) {
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}
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}
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void f6() {
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try {
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} catch (B &b) { // expected-note {{for type 'B &'}}
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} catch (D2 &d) { // expected-warning {{exception of type 'D2 &' will be caught by earlier handler}}
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}
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}
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void f7() {
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try {
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} catch (B *b) { // Ok
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} catch (D &d) { // Ok
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}
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try {
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} catch (B b) { // Ok
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} catch (D *d) { // Ok
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}
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}
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void f8() {
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try {
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} catch (const B &b) { // expected-note {{for type 'const B &'}}
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} catch (D2 &d) { // expected-warning {{exception of type 'D2 &' will be caught by earlier handler}}
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}
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try {
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} catch (B &b) { // expected-note {{for type 'B &'}}
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} catch (const D2 &d) { // expected-warning {{exception of type 'const D2 &' will be caught by earlier handler}}
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}
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try {
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} catch (B b) { // expected-note {{for type 'B'}}
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} catch (D &d) { // expected-warning {{exception of type 'D &' will be caught by earlier handler}}
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}
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}
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}
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namespace ConstVolatileThrow {
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struct S {
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S() {} // expected-note{{candidate constructor not viable}}
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S(const S &s); // expected-note{{candidate constructor not viable}}
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};
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typedef const volatile S CVS;
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void f() {
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throw CVS(); // expected-error{{no matching constructor for initialization}}
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}
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}
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namespace ConstVolatileCatch {
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struct S {
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S() {}
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S(const volatile S &s);
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private:
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S(const S &s); // expected-note {{declared private here}}
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};
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void f();
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void g() {
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try {
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f();
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} catch (volatile S s) { // expected-error {{calling a private constructor}}
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}
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}
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}
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namespace PR28047 {
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void test1(int i) {
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try {
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} catch (int(*)[i]) { // expected-error{{cannot catch variably modified type}}
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}
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}
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void test2() {
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int i;
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try {
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} catch (int(*)[i]) { // expected-error{{cannot catch variably modified type}}
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}
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}
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}
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