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| author | Alon Zakai <azakai@google.com> | 2019-12-19 09:04:08 -0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-12-19 09:04:08 -0800 |
| commit | 4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6 (patch) | |
| tree | 91bffc2d47b1fe4bba01e7ada77006ef340bd138 /third_party/llvm-project/include/llvm/Support/Casting.h | |
| parent | 0048f5b004ddf50e750aa335d0be314a73852058 (diff) | |
| download | binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.tar.gz binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.tar.bz2 binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.zip | |
DWARF parsing and writing support using LLVM (#2520)
This imports LLVM code for DWARF handling. That code has the
Apache 2 license like us. It's also the same code used to
emit DWARF in the common toolchain, so it seems like a safe choice.
This adds two passes: --dwarfdump which runs the same code LLVM
runs for llvm-dwarfdump. This shows we can parse it ok, and will
be useful for debugging. And --dwarfupdate writes out the DWARF
sections (unchanged from what we read, so it just roundtrips - for
updating we need #2515).
This puts LLVM in thirdparty which is added here.
All the LLVM code is behind USE_LLVM_DWARF, which is on
by default, but off in JS for now, as it increases code size by 20%.
This current approach imports the LLVM files directly. This is not
how they are intended to be used, so it required a bunch of
local changes - more than I expected actually, for the platform-specific
stuff. For now this seems to work, so it may be good enough, but
in the long term we may want to switch to linking against libllvm.
A downside to doing that is that binaryen users would need to
have an LLVM build, and even in the waterfall builds we'd have a
problem - while we ship LLVM there anyhow, we constantly update
it, which means that binaryen would need to be on latest llvm all
the time too (which otherwise, given DWARF is quite stable, we
might not need to constantly update).
An even larger issue is that as I did this work I learned about how
DWARF works in LLVM, and while the reading code is easy to
reuse, the writing code is trickier. The main code path is heavily
integrated with the MC layer, which we don't have - we might want
to create a "fake MC layer" for that, but it sounds hard. Instead,
there is the YAML path which is used mostly for testing, and which
can convert DWARF to and from YAML and from binary. Using
the non-YAML parts there, we can convert binary DWARF to
the YAML layer's nice Info data, then convert that to binary. This
works, however, this is not the path LLVM uses normally, and it
supports only some basic DWARF sections - I had to add ranges
support, in fact. So if we need more complex things, we may end
up needing to use the MC layer approach, or consider some other
DWARF library. However, hopefully that should not affect the core
binaryen code which just calls a library for DWARF stuff.
Helps #2400
Diffstat (limited to 'third_party/llvm-project/include/llvm/Support/Casting.h')
| -rw-r--r-- | third_party/llvm-project/include/llvm/Support/Casting.h | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/third_party/llvm-project/include/llvm/Support/Casting.h b/third_party/llvm-project/include/llvm/Support/Casting.h new file mode 100644 index 000000000..46bdedb04 --- /dev/null +++ b/third_party/llvm-project/include/llvm/Support/Casting.h @@ -0,0 +1,408 @@ +//===- llvm/Support/Casting.h - Allow flexible, checked, casts --*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines the isa<X>(), cast<X>(), dyn_cast<X>(), cast_or_null<X>(), +// and dyn_cast_or_null<X>() templates. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_CASTING_H +#define LLVM_SUPPORT_CASTING_H + +#include "llvm/Support/Compiler.h" +#include "llvm/Support/type_traits.h" +#include <cassert> +#include <memory> +#include <type_traits> + +namespace llvm { + +//===----------------------------------------------------------------------===// +// isa<x> Support Templates +//===----------------------------------------------------------------------===// + +// Define a template that can be specialized by smart pointers to reflect the +// fact that they are automatically dereferenced, and are not involved with the +// template selection process... the default implementation is a noop. +// +template<typename From> struct simplify_type { + using SimpleType = From; // The real type this represents... + + // An accessor to get the real value... + static SimpleType &getSimplifiedValue(From &Val) { return Val; } +}; + +template<typename From> struct simplify_type<const From> { + using NonConstSimpleType = typename simplify_type<From>::SimpleType; + using SimpleType = + typename add_const_past_pointer<NonConstSimpleType>::type; + using RetType = + typename add_lvalue_reference_if_not_pointer<SimpleType>::type; + + static RetType getSimplifiedValue(const From& Val) { + return simplify_type<From>::getSimplifiedValue(const_cast<From&>(Val)); + } +}; + +// The core of the implementation of isa<X> is here; To and From should be +// the names of classes. This template can be specialized to customize the +// implementation of isa<> without rewriting it from scratch. +template <typename To, typename From, typename Enabler = void> +struct isa_impl { + static inline bool doit(const From &Val) { + return To::classof(&Val); + } +}; + +/// Always allow upcasts, and perform no dynamic check for them. +template <typename To, typename From> +struct isa_impl< + To, From, typename std::enable_if<std::is_base_of<To, From>::value>::type> { + static inline bool doit(const From &) { return true; } +}; + +template <typename To, typename From> struct isa_impl_cl { + static inline bool doit(const From &Val) { + return isa_impl<To, From>::doit(Val); + } +}; + +template <typename To, typename From> struct isa_impl_cl<To, const From> { + static inline bool doit(const From &Val) { + return isa_impl<To, From>::doit(Val); + } +}; + +template <typename To, typename From> +struct isa_impl_cl<To, const std::unique_ptr<From>> { + static inline bool doit(const std::unique_ptr<From> &Val) { + assert(Val && "isa<> used on a null pointer"); + return isa_impl_cl<To, From>::doit(*Val); + } +}; + +template <typename To, typename From> struct isa_impl_cl<To, From*> { + static inline bool doit(const From *Val) { + assert(Val && "isa<> used on a null pointer"); + return isa_impl<To, From>::doit(*Val); + } +}; + +template <typename To, typename From> struct isa_impl_cl<To, From*const> { + static inline bool doit(const From *Val) { + assert(Val && "isa<> used on a null pointer"); + return isa_impl<To, From>::doit(*Val); + } +}; + +template <typename To, typename From> struct isa_impl_cl<To, const From*> { + static inline bool doit(const From *Val) { + assert(Val && "isa<> used on a null pointer"); + return isa_impl<To, From>::doit(*Val); + } +}; + +template <typename To, typename From> struct isa_impl_cl<To, const From*const> { + static inline bool doit(const From *Val) { + assert(Val && "isa<> used on a null pointer"); + return isa_impl<To, From>::doit(*Val); + } +}; + +template<typename To, typename From, typename SimpleFrom> +struct isa_impl_wrap { + // When From != SimplifiedType, we can simplify the type some more by using + // the simplify_type template. + static bool doit(const From &Val) { + return isa_impl_wrap<To, SimpleFrom, + typename simplify_type<SimpleFrom>::SimpleType>::doit( + simplify_type<const From>::getSimplifiedValue(Val)); + } +}; + +template<typename To, typename FromTy> +struct isa_impl_wrap<To, FromTy, FromTy> { + // When From == SimpleType, we are as simple as we are going to get. + static bool doit(const FromTy &Val) { + return isa_impl_cl<To,FromTy>::doit(Val); + } +}; + +// isa<X> - Return true if the parameter to the template is an instance of the +// template type argument. Used like this: +// +// if (isa<Type>(myVal)) { ... } +// +template <class X, class Y> LLVM_NODISCARD inline bool isa(const Y &Val) { + return isa_impl_wrap<X, const Y, + typename simplify_type<const Y>::SimpleType>::doit(Val); +} + +// isa_and_nonnull<X> - Functionally identical to isa, except that a null value +// is accepted. +// +template <class X, class Y> +LLVM_NODISCARD inline bool isa_and_nonnull(const Y &Val) { + if (!Val) + return false; + return isa<X>(Val); +} + +//===----------------------------------------------------------------------===// +// cast<x> Support Templates +//===----------------------------------------------------------------------===// + +template<class To, class From> struct cast_retty; + +// Calculate what type the 'cast' function should return, based on a requested +// type of To and a source type of From. +template<class To, class From> struct cast_retty_impl { + using ret_type = To &; // Normal case, return Ty& +}; +template<class To, class From> struct cast_retty_impl<To, const From> { + using ret_type = const To &; // Normal case, return Ty& +}; + +template<class To, class From> struct cast_retty_impl<To, From*> { + using ret_type = To *; // Pointer arg case, return Ty* +}; + +template<class To, class From> struct cast_retty_impl<To, const From*> { + using ret_type = const To *; // Constant pointer arg case, return const Ty* +}; + +template<class To, class From> struct cast_retty_impl<To, const From*const> { + using ret_type = const To *; // Constant pointer arg case, return const Ty* +}; + +template <class To, class From> +struct cast_retty_impl<To, std::unique_ptr<From>> { +private: + using PointerType = typename cast_retty_impl<To, From *>::ret_type; + using ResultType = typename std::remove_pointer<PointerType>::type; + +public: + using ret_type = std::unique_ptr<ResultType>; +}; + +template<class To, class From, class SimpleFrom> +struct cast_retty_wrap { + // When the simplified type and the from type are not the same, use the type + // simplifier to reduce the type, then reuse cast_retty_impl to get the + // resultant type. + using ret_type = typename cast_retty<To, SimpleFrom>::ret_type; +}; + +template<class To, class FromTy> +struct cast_retty_wrap<To, FromTy, FromTy> { + // When the simplified type is equal to the from type, use it directly. + using ret_type = typename cast_retty_impl<To,FromTy>::ret_type; +}; + +template<class To, class From> +struct cast_retty { + using ret_type = typename cast_retty_wrap< + To, From, typename simplify_type<From>::SimpleType>::ret_type; +}; + +// Ensure the non-simple values are converted using the simplify_type template +// that may be specialized by smart pointers... +// +template<class To, class From, class SimpleFrom> struct cast_convert_val { + // This is not a simple type, use the template to simplify it... + static typename cast_retty<To, From>::ret_type doit(From &Val) { + return cast_convert_val<To, SimpleFrom, + typename simplify_type<SimpleFrom>::SimpleType>::doit( + simplify_type<From>::getSimplifiedValue(Val)); + } +}; + +template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> { + // This _is_ a simple type, just cast it. + static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) { + typename cast_retty<To, FromTy>::ret_type Res2 + = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val); + return Res2; + } +}; + +template <class X> struct is_simple_type { + static const bool value = + std::is_same<X, typename simplify_type<X>::SimpleType>::value; +}; + +// cast<X> - Return the argument parameter cast to the specified type. This +// casting operator asserts that the type is correct, so it does not return null +// on failure. It does not allow a null argument (use cast_or_null for that). +// It is typically used like this: +// +// cast<Instruction>(myVal)->getParent() +// +template <class X, class Y> +inline typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, const Y>::ret_type>::type +cast(const Y &Val) { + assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!"); + return cast_convert_val< + X, const Y, typename simplify_type<const Y>::SimpleType>::doit(Val); +} + +template <class X, class Y> +inline typename cast_retty<X, Y>::ret_type cast(Y &Val) { + assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!"); + return cast_convert_val<X, Y, + typename simplify_type<Y>::SimpleType>::doit(Val); +} + +template <class X, class Y> +inline typename cast_retty<X, Y *>::ret_type cast(Y *Val) { + assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!"); + return cast_convert_val<X, Y*, + typename simplify_type<Y*>::SimpleType>::doit(Val); +} + +template <class X, class Y> +inline typename cast_retty<X, std::unique_ptr<Y>>::ret_type +cast(std::unique_ptr<Y> &&Val) { + assert(isa<X>(Val.get()) && "cast<Ty>() argument of incompatible type!"); + using ret_type = typename cast_retty<X, std::unique_ptr<Y>>::ret_type; + return ret_type( + cast_convert_val<X, Y *, typename simplify_type<Y *>::SimpleType>::doit( + Val.release())); +} + +// cast_or_null<X> - Functionally identical to cast, except that a null value is +// accepted. +// +template <class X, class Y> +LLVM_NODISCARD inline + typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, const Y>::ret_type>::type + cast_or_null(const Y &Val) { + if (!Val) + return nullptr; + assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!"); + return cast<X>(Val); +} + +template <class X, class Y> +LLVM_NODISCARD inline + typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, Y>::ret_type>::type + cast_or_null(Y &Val) { + if (!Val) + return nullptr; + assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!"); + return cast<X>(Val); +} + +template <class X, class Y> +LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type +cast_or_null(Y *Val) { + if (!Val) return nullptr; + assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!"); + return cast<X>(Val); +} + +template <class X, class Y> +inline typename cast_retty<X, std::unique_ptr<Y>>::ret_type +cast_or_null(std::unique_ptr<Y> &&Val) { + if (!Val) + return nullptr; + return cast<X>(std::move(Val)); +} + +// dyn_cast<X> - Return the argument parameter cast to the specified type. This +// casting operator returns null if the argument is of the wrong type, so it can +// be used to test for a type as well as cast if successful. This should be +// used in the context of an if statement like this: +// +// if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... } +// + +template <class X, class Y> +LLVM_NODISCARD inline + typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, const Y>::ret_type>::type + dyn_cast(const Y &Val) { + return isa<X>(Val) ? cast<X>(Val) : nullptr; +} + +template <class X, class Y> +LLVM_NODISCARD inline typename cast_retty<X, Y>::ret_type dyn_cast(Y &Val) { + return isa<X>(Val) ? cast<X>(Val) : nullptr; +} + +template <class X, class Y> +LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type dyn_cast(Y *Val) { + return isa<X>(Val) ? cast<X>(Val) : nullptr; +} + +// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null +// value is accepted. +// +template <class X, class Y> +LLVM_NODISCARD inline + typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, const Y>::ret_type>::type + dyn_cast_or_null(const Y &Val) { + return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr; +} + +template <class X, class Y> +LLVM_NODISCARD inline + typename std::enable_if<!is_simple_type<Y>::value, + typename cast_retty<X, Y>::ret_type>::type + dyn_cast_or_null(Y &Val) { + return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr; +} + +template <class X, class Y> +LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type +dyn_cast_or_null(Y *Val) { + return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr; +} + +// unique_dyn_cast<X> - Given a unique_ptr<Y>, try to return a unique_ptr<X>, +// taking ownership of the input pointer iff isa<X>(Val) is true. If the +// cast is successful, From refers to nullptr on exit and the casted value +// is returned. If the cast is unsuccessful, the function returns nullptr +// and From is unchanged. +template <class X, class Y> +LLVM_NODISCARD inline auto unique_dyn_cast(std::unique_ptr<Y> &Val) + -> decltype(cast<X>(Val)) { + if (!isa<X>(Val)) + return nullptr; + return cast<X>(std::move(Val)); +} + +template <class X, class Y> +LLVM_NODISCARD inline auto unique_dyn_cast(std::unique_ptr<Y> &&Val) + -> decltype(cast<X>(Val)) { + return unique_dyn_cast<X, Y>(Val); +} + +// dyn_cast_or_null<X> - Functionally identical to unique_dyn_cast, except that +// a null value is accepted. +template <class X, class Y> +LLVM_NODISCARD inline auto unique_dyn_cast_or_null(std::unique_ptr<Y> &Val) + -> decltype(cast<X>(Val)) { + if (!Val) + return nullptr; + return unique_dyn_cast<X, Y>(Val); +} + +template <class X, class Y> +LLVM_NODISCARD inline auto unique_dyn_cast_or_null(std::unique_ptr<Y> &&Val) + -> decltype(cast<X>(Val)) { + return unique_dyn_cast_or_null<X, Y>(Val); +} + +} // end namespace llvm + +#endif // LLVM_SUPPORT_CASTING_H |