2018-03-22 03:19:48 +08:00
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// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s \
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// RUN: -faligned-allocation -fsized-deallocation -emit-llvm -o - \
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// RUN: | FileCheck %s
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typedef __SIZE_TYPE__ size_t;
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// Declare an 'operator new' template to tickle a bug in __builtin_operator_new.
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template<typename T> void *operator new(size_t, int (*)(T));
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// Ensure that this declaration doesn't cause operator new to lose its
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// 'noalias' attribute.
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void *operator new(size_t);
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namespace std {
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struct nothrow_t {};
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enum class align_val_t : size_t { __zero = 0,
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__max = (size_t)-1 };
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}
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std::nothrow_t nothrow;
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// Declare the reserved placement operators.
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void *operator new(size_t, void*) throw();
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void operator delete(void*, void*) throw();
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void *operator new[](size_t, void*) throw();
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void operator delete[](void*, void*) throw();
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// Declare the replaceable global allocation operators.
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void *operator new(size_t, const std::nothrow_t &) throw();
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void *operator new[](size_t, const std::nothrow_t &) throw();
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void operator delete(void *, const std::nothrow_t &) throw();
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void operator delete[](void *, const std::nothrow_t &) throw();
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// Declare some other placement operators.
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void *operator new(size_t, void*, bool) throw();
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void *operator new[](size_t, void*, bool) throw();
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2020-12-31 16:27:11 +08:00
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// CHECK-LABEL: define{{.*}} void @test_basic(
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2018-03-22 03:19:48 +08:00
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extern "C" void test_basic() {
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[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.
However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.
Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.
The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.
Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith
Reviewed By: rsmith
Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 06:37:17 +08:00
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// CHECK: call noalias nonnull i8* @_Znwm(i64 4) [[ATTR_BUILTIN_NEW:#[^ ]*]]
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2018-03-22 03:19:48 +08:00
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// CHECK: call void @_ZdlPv({{.*}}) [[ATTR_BUILTIN_DELETE:#[^ ]*]]
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// CHECK: ret void
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__builtin_operator_delete(__builtin_operator_new(4));
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}
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[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.
However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.
Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.
The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.
Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith
Reviewed By: rsmith
Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 06:37:17 +08:00
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// CHECK: declare nonnull i8* @_Znwm(i64) [[ATTR_NOBUILTIN:#[^ ]*]]
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2018-03-22 03:19:48 +08:00
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// CHECK: declare void @_ZdlPv(i8*) [[ATTR_NOBUILTIN_NOUNWIND:#[^ ]*]]
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2020-12-31 16:27:11 +08:00
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// CHECK-LABEL: define{{.*}} void @test_aligned_alloc(
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2018-03-22 03:19:48 +08:00
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extern "C" void test_aligned_alloc() {
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[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.
However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.
Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.
The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.
Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith
Reviewed By: rsmith
Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 06:37:17 +08:00
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// CHECK: call noalias nonnull align 4 i8* @_ZnwmSt11align_val_t(i64 4, i64 4) [[ATTR_BUILTIN_NEW:#[^ ]*]]
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2018-03-22 03:19:48 +08:00
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// CHECK: call void @_ZdlPvSt11align_val_t({{.*}}, i64 4) [[ATTR_BUILTIN_DELETE:#[^ ]*]]
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__builtin_operator_delete(__builtin_operator_new(4, std::align_val_t(4)), std::align_val_t(4));
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}
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[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.
However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.
Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.
The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.
Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith
Reviewed By: rsmith
Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 06:37:17 +08:00
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// CHECK: declare nonnull i8* @_ZnwmSt11align_val_t(i64, i64) [[ATTR_NOBUILTIN:#[^ ]*]]
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2018-03-22 03:19:48 +08:00
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// CHECK: declare void @_ZdlPvSt11align_val_t(i8*, i64) [[ATTR_NOBUILTIN_NOUNWIND:#[^ ]*]]
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2020-12-31 16:27:11 +08:00
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// CHECK-LABEL: define{{.*}} void @test_sized_delete(
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2018-03-22 03:19:48 +08:00
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extern "C" void test_sized_delete() {
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[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.
However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.
Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.
The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.
Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith
Reviewed By: rsmith
Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 06:37:17 +08:00
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// CHECK: call noalias nonnull i8* @_Znwm(i64 4) [[ATTR_BUILTIN_NEW:#[^ ]*]]
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2018-03-22 03:19:48 +08:00
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// CHECK: call void @_ZdlPvm({{.*}}, i64 4) [[ATTR_BUILTIN_DELETE:#[^ ]*]]
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__builtin_operator_delete(__builtin_operator_new(4), 4);
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}
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// CHECK: declare void @_ZdlPvm(i8*, i64) [[ATTR_NOBUILTIN_UNWIND:#[^ ]*]]
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// CHECK-DAG: attributes [[ATTR_NOBUILTIN]] = {{[{].*}} nobuiltin {{.*[}]}}
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// CHECK-DAG: attributes [[ATTR_NOBUILTIN_NOUNWIND]] = {{[{].*}} nobuiltin nounwind {{.*[}]}}
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// CHECK-DAG: attributes [[ATTR_BUILTIN_NEW]] = {{[{].*}} builtin {{.*[}]}}
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// CHECK-DAG: attributes [[ATTR_BUILTIN_DELETE]] = {{[{].*}} builtin {{.*[}]}}
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