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llvm-project/clang/test/Sema/attr-notail.c

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Add support for function attribute 'not_tail_called'. This attribute is used to prevent tail-call optimizations to the marked function. For example, in the following piece of code, foo1 will not be tail-call optimized: int __attribute__((not_tail_called)) foo1(int); int foo2(int a) { return foo1(a); // Tail-call optimization is not performed. } The attribute has effect only on statically bound calls. It has no effect on indirect calls. Also, virtual functions and objective-c methods cannot be marked as 'not_tail_called'. rdar://problem/22667622 Differential Revision: http://reviews.llvm.org/D12922 llvm-svn: 252369
2015-11-07 07:56:15 +08:00
// RUN: %clang_cc1 -fsyntax-only -verify %s
Append new attributes to the end of an AttributeList. Recommit of r335084 after revert in r335516. ... instead of prepending it at the beginning (the original behavior since implemented in r122535 2010-12-23). This builds up an AttributeList in the the order in which the attributes appear in the source. The reverse order caused nodes for attributes in the AST (e.g. LoopHint) to be in the reverse order, and therefore printed in the wrong order in -ast-dump. Some TODO comments mention this. The order was explicitly reversed for enable_if attribute overload resolution and name mangling, which is not necessary anymore with this patch. The change unfortunately has some secondary effect, especially on diagnostic output. In the simplest cases, the CHECK lines or expected diagnostic were changed to the the new output. If the kind of error/warning changed, the attributes' order was changed instead. This unfortunately causes some 'previous occurrence here' hints to be textually after the main marker. This typically happens when attributes are merged, but are incompatible to each other. Interchanging the role of the the main and note SourceLocation will also cause the case where two different declaration's attributes (in contrast to multiple attributes of the same declaration) are merged to be reverse. There is no easy fix because sometimes previous attributes are merged into a new declaration's attribute list, sometimes new attributes are added to a previous declaration's attribute list. Since 'previous occurrence here' pointing to locations after the main marker is not rare, I left the markers as-is; it is only relevant when the attributes are declared in the same declaration anyway. Differential Revision: https://reviews.llvm.org/D48100 llvm-svn: 338800
2018-08-03 09:21:16 +08:00
int callee0() __attribute__((not_tail_called,always_inline)); // expected-error{{'always_inline' and 'not_tail_called' attributes are not compatible}} \
Implement __attribute__((internal_linkage)). The attrubite is applicable to functions and variables and changes the linkage of the subject to internal. This is the same functionality as C-style "static", but applicable to class methods; and the same as anonymouns namespaces, but can apply to individual methods of a class. Following the proposal in http://lists.llvm.org/pipermail/cfe-dev/2015-October/045580.html llvm-svn: 252648
2015-11-11 05:28:44 +08:00
// expected-note{{conflicting attribute is here}}
Append new attributes to the end of an AttributeList. Recommit of r335084 after revert in r335516. ... instead of prepending it at the beginning (the original behavior since implemented in r122535 2010-12-23). This builds up an AttributeList in the the order in which the attributes appear in the source. The reverse order caused nodes for attributes in the AST (e.g. LoopHint) to be in the reverse order, and therefore printed in the wrong order in -ast-dump. Some TODO comments mention this. The order was explicitly reversed for enable_if attribute overload resolution and name mangling, which is not necessary anymore with this patch. The change unfortunately has some secondary effect, especially on diagnostic output. In the simplest cases, the CHECK lines or expected diagnostic were changed to the the new output. If the kind of error/warning changed, the attributes' order was changed instead. This unfortunately causes some 'previous occurrence here' hints to be textually after the main marker. This typically happens when attributes are merged, but are incompatible to each other. Interchanging the role of the the main and note SourceLocation will also cause the case where two different declaration's attributes (in contrast to multiple attributes of the same declaration) are merged to be reverse. There is no easy fix because sometimes previous attributes are merged into a new declaration's attribute list, sometimes new attributes are added to a previous declaration's attribute list. Since 'previous occurrence here' pointing to locations after the main marker is not rare, I left the markers as-is; it is only relevant when the attributes are declared in the same declaration anyway. Differential Revision: https://reviews.llvm.org/D48100 llvm-svn: 338800
2018-08-03 09:21:16 +08:00
int callee1() __attribute__((always_inline,not_tail_called)); // expected-error{{'not_tail_called' and 'always_inline' attributes are not compatible}} \
Implement __attribute__((internal_linkage)). The attrubite is applicable to functions and variables and changes the linkage of the subject to internal. This is the same functionality as C-style "static", but applicable to class methods; and the same as anonymouns namespaces, but can apply to individual methods of a class. Following the proposal in http://lists.llvm.org/pipermail/cfe-dev/2015-October/045580.html llvm-svn: 252648
2015-11-11 05:28:44 +08:00
// expected-note{{conflicting attribute is here}}
Add support for function attribute 'not_tail_called'. This attribute is used to prevent tail-call optimizations to the marked function. For example, in the following piece of code, foo1 will not be tail-call optimized: int __attribute__((not_tail_called)) foo1(int); int foo2(int a) { return foo1(a); // Tail-call optimization is not performed. } The attribute has effect only on statically bound calls. It has no effect on indirect calls. Also, virtual functions and objective-c methods cannot be marked as 'not_tail_called'. rdar://problem/22667622 Differential Revision: http://reviews.llvm.org/D12922 llvm-svn: 252369
2015-11-07 07:56:15 +08:00
int foo(int a) {
return a ? callee0() : callee1();
}
int g0 __attribute__((not_tail_called)); // expected-warning {{'not_tail_called' attribute only applies to functions}}
int foo2(int a) __attribute__((not_tail_called("abc"))); // expected-error {{'not_tail_called' attribute takes no arguments}}