[llvm] r280750 - Avoid using alignas and constexpr.
Justin Bogner via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 19 00:02:13 PDT 2016
Rafael Espindola via llvm-commits <llvm-commits at lists.llvm.org> writes:
> Author: rafael
> Date: Tue Sep 6 15:36:24 2016
> New Revision: 280750
>
> URL: http://llvm.org/viewvc/llvm-project?rev=280750&view=rev
> Log:
> Avoid using alignas and constexpr.
>
> This requires removing the custom allocator, since Demangle cannot
> depend on Support and so cannot use Compiler.h.
Can we use alignas and constexpr now that we're dropping MSVC 2013, or
did these also cause problems on other compilers? If 2013 was the
bottleneck, should we add back the custom allocator here?
> Modified:
> llvm/trunk/lib/Demangle/ItaniumDemangle.cpp
>
> Modified: llvm/trunk/lib/Demangle/ItaniumDemangle.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Demangle/ItaniumDemangle.cpp?rev=280750&r1=280749&r2=280750&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Demangle/ItaniumDemangle.cpp (original)
> +++ llvm/trunk/lib/Demangle/ItaniumDemangle.cpp Tue Sep 6 15:36:24 2016
> @@ -8,7 +8,6 @@
> //===----------------------------------------------------------------------===//
>
> #include "llvm/Demangle/Demangle.h"
> -#include "llvm/Support/Compiler.h"
>
> // This file exports a single function: llvm::itanium_demangle.
> // It also has no dependencies on the rest of llvm. It is implemented this way
> @@ -4210,134 +4209,7 @@ static void demangle(const char *first,
> }
>
> namespace {
> -template <std::size_t N> class arena {
> - static const std::size_t alignment = 16;
> - LLVM_ALIGNAS(16) char buf_[N];
> - char *ptr_;
> -
> - std::size_t align_up(std::size_t n) LLVM_NOEXCEPT {
> - return (n + (alignment - 1)) & ~(alignment - 1);
> - }
> -
> - bool pointer_in_buffer(char *p) LLVM_NOEXCEPT {
> - return buf_ <= p && p <= buf_ + N;
> - }
> -
> -public:
> - arena() LLVM_NOEXCEPT : ptr_(buf_) {}
> - ~arena() { ptr_ = nullptr; }
> - arena(const arena &) = delete;
> - arena &operator=(const arena &) = delete;
> -
> - char *allocate(std::size_t n);
> - void deallocate(char *p, std::size_t n) LLVM_NOEXCEPT;
> -
> - static LLVM_CONSTEXPR std::size_t size() { return N; }
> - std::size_t used() const { return static_cast<std::size_t>(ptr_ - buf_); }
> - void reset() { ptr_ = buf_; }
> -};
> -
> -template <std::size_t N> char *arena<N>::allocate(std::size_t n) {
> - n = align_up(n);
> - if (static_cast<std::size_t>(buf_ + N - ptr_) >= n) {
> - char *r = ptr_;
> - ptr_ += n;
> - return r;
> - }
> - return static_cast<char *>(std::malloc(n));
> -}
> -
> -template <std::size_t N>
> -void arena<N>::deallocate(char *p, std::size_t n) LLVM_NOEXCEPT {
> - if (pointer_in_buffer(p)) {
> - n = align_up(n);
> - if (p + n == ptr_)
> - ptr_ = p;
> - } else
> - std::free(p);
> -}
> -
> -template <class T, std::size_t N> class short_alloc {
> - arena<N> &a_;
> -
> -public:
> - typedef T value_type;
> -
> -public:
> - template <class _Up> struct rebind { typedef short_alloc<_Up, N> other; };
> -
> - short_alloc(arena<N> &a) LLVM_NOEXCEPT : a_(a) {}
> - template <class U>
> - short_alloc(const short_alloc<U, N> &a) LLVM_NOEXCEPT : a_(a.a_) {}
> - short_alloc(const short_alloc &) = default;
> - short_alloc &operator=(const short_alloc &) = delete;
> -
> - T *allocate(std::size_t n) {
> - return reinterpret_cast<T *>(a_.allocate(n * sizeof(T)));
> - }
> - void deallocate(T *p, std::size_t n) LLVM_NOEXCEPT {
> - a_.deallocate(reinterpret_cast<char *>(p), n * sizeof(T));
> - }
> -
> - template <class T1, std::size_t N1, class U, std::size_t M>
> - friend bool operator==(const short_alloc<T1, N1> &x,
> - const short_alloc<U, M> &y) LLVM_NOEXCEPT;
> -
> - template <class U, std::size_t M> friend class short_alloc;
> -};
> -
> -template <class T, std::size_t N, class U, std::size_t M>
> -inline bool operator==(const short_alloc<T, N> &x,
> - const short_alloc<U, M> &y) LLVM_NOEXCEPT {
> - return N == M && &x.a_ == &y.a_;
> -}
> -
> -template <class T, std::size_t N, class U, std::size_t M>
> -inline bool operator!=(const short_alloc<T, N> &x,
> - const short_alloc<U, M> &y) LLVM_NOEXCEPT {
> - return !(x == y);
> -}
> -
> -template <class T> class malloc_alloc {
> -public:
> - typedef T value_type;
> - typedef T &reference;
> - typedef const T &const_reference;
> - typedef T *pointer;
> - typedef const T *const_pointer;
> - typedef std::size_t size_type;
> - typedef std::ptrdiff_t difference_type;
> -
> - malloc_alloc() = default;
> - template <class U> malloc_alloc(const malloc_alloc<U> &) LLVM_NOEXCEPT {}
> -
> - T *allocate(std::size_t n) {
> - return static_cast<T *>(std::malloc(n * sizeof(T)));
> - }
> - void deallocate(T *p, std::size_t) LLVM_NOEXCEPT { std::free(p); }
> -
> - template <class U> struct rebind { using other = malloc_alloc<U>; };
> - template <class U, class... Args> void construct(U *p, Args &&... args) {
> - ::new ((void *)p) U(std::forward<Args>(args)...);
> - }
> - void destroy(T *p) { p->~T(); }
> -};
> -
> -template <class T, class U>
> -inline bool operator==(const malloc_alloc<T> &,
> - const malloc_alloc<U> &) LLVM_NOEXCEPT {
> - return true;
> -}
> -
> -template <class T, class U>
> -inline bool operator!=(const malloc_alloc<T> &x,
> - const malloc_alloc<U> &y) LLVM_NOEXCEPT {
> - return !(x == y);
> -}
> -
> -const size_t bs = 4 * 1024;
> -template <class T> using Alloc = short_alloc<T, bs>;
> -template <class T> using Vector = std::vector<T, Alloc<T>>;
> +template <class T> using Vector = std::vector<T>;
>
> template <class StrT> struct string_pair {
> StrT first;
> @@ -4354,7 +4226,7 @@ template <class StrT> struct string_pair
> };
>
> struct Db {
> - typedef std::basic_string<char, std::char_traits<char>, malloc_alloc<char>>
> + typedef std::basic_string<char, std::char_traits<char>>
> String;
> typedef Vector<string_pair<String>> sub_type;
> typedef Vector<sub_type> template_param_type;
> @@ -4369,9 +4241,7 @@ struct Db {
> bool fix_forward_references;
> bool try_to_parse_template_args;
>
> - template <size_t N>
> - Db(arena<N> &ar)
> - : names(ar), subs(0, names, ar), template_param(0, subs, ar) {}
> + Db() : subs(0, names), template_param(0, subs) {}
> };
> }
>
> @@ -4383,14 +4253,13 @@ char *llvm::itaniumDemangle(const char *
> return nullptr;
> }
> size_t internal_size = buf != nullptr ? *n : 0;
> - arena<bs> a;
> - Db db(a);
> + Db db;
> db.cv = 0;
> db.ref = 0;
> db.encoding_depth = 0;
> db.parsed_ctor_dtor_cv = false;
> db.tag_templates = true;
> - db.template_param.emplace_back(a);
> + db.template_param.emplace_back();
> db.fix_forward_references = false;
> db.try_to_parse_template_args = true;
> int internal_status = success;
>
>
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