[PATCH v2 3/5] Add gdb::string_view
Simon Marchi
simon.marchi@polymtl.ca
Fri Mar 30 21:47:00 GMT 2018
We had a few times the need for a data structure that does essentially
what C++17's std::string_view does, which is to give an std::string-like
interface (only the read-only operations) to an arbitrary character
buffer.
This patch adapts the files copied from libstdc++ by the previous patch
to integrate them with GDB. Here's a summary of the changes:
* Remove things related to wstring_view, u16string_view and
u32string_view (I don't think we need them, but we can always add them
later).
* Remove usages of _GLIBCXX_BEGIN_NAMESPACE_VERSION and
_GLIBCXX_END_NAMESPACE_VERSION.
* Put the code in the gdb namespace. I had to add a few "std::" in
front of std type usages.
* Add a constructor that builds a string_view from an std::string, so
that we can pass strings to string_view parameters seamlessly.
Normally, that's handled by "operator __sv_type" in the std::string
declaration, but it only exists when building with c++17.
* Change __throw_out_of_range_fmt() for error().
* Make gdb::string_view and alias of std::string_view when building
with >= c++17.
* Remove a bunch of constexpr, because they are not valid in c++11
(e.g. they are not a single return line).
* Use std::common_type<_Tp>::type instead of std::common_type_t<_Tp>,
because c++11 doesn't have the later.
* Remove the #pragma GCC system_header, since that silences some
warnings that we might want to have if we're doing something not
correctly.
* GCC complains about us defining the ""sv user-defined literal,
because user code is supposed to use suffixes that begin with _.
However, we only use that code with c++ < 17, where we know the sv
literal is not defined. Recent GCCs allow turning off the warning
(-Wliteral-suffix), but gcc 4.8.4 (what the GCC compile farm ARM
builders have) don't have a way to silence this warning. The only way
I found was to add back #pragma GCC system_header, but at least I
could add it at the very end of the file. The pragma only makes the
rest of the file (what follows it) part of a system header, so the
code above should not be considered a system header.
The string_view class in cli/cli-script.c is removed and its usage
replaced with the new gdb::string_view.
gdb/ChangeLog:
* common/string_view.h: Remove libstdc++ implementation details,
adjust to gdb reality.
* common/string_view.tcc: Likewise.
* cli/cli-script.c (struct string_view): Remove.
(user_args) <m_args>: Change element type to gdb::string_view.
(user_args::insert_args): Adjust.
---
gdb/cli/cli-script.c | 17 +---
gdb/common/string_view.h | 188 +++++++++++++++------------------------------
gdb/common/string_view.tcc | 43 +++++------
3 files changed, 82 insertions(+), 166 deletions(-)
diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index 366c42227c62..e705b7a8da70 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -32,6 +32,7 @@
#include "extension.h"
#include "interps.h"
#include "compile/compile.h"
+#include "common/string_view.h"
#include <vector>
@@ -54,18 +55,6 @@ static int command_nest_depth = 1;
/* This is to prevent certain commands being printed twice. */
static int suppress_next_print_command_trace = 0;
-/* A non-owning slice of a string. */
-
-struct string_view
-{
- string_view (const char *str_, size_t len_)
- : str (str_), len (len_)
- {}
-
- const char *str;
- size_t len;
-};
-
/* Structure for arguments to user defined functions. */
class user_args
@@ -91,7 +80,7 @@ private:
std::string m_command_line;
/* The arguments. Each element points inside M_COMMAND_LINE. */
- std::vector<string_view> m_args;
+ std::vector<gdb::string_view> m_args;
};
/* The stack of arguments passed to user defined functions. We need a
@@ -827,7 +816,7 @@ user_args::insert_args (const char *line) const
error (_("Missing argument %ld in user function."), i);
else
{
- new_line.append (m_args[i].str, m_args[i].len);
+ new_line.append (m_args[i].data (), m_args[i].length ());
line = tmp;
}
}
diff --git a/gdb/common/string_view.h b/gdb/common/string_view.h
index 9f39df853e8d..06bf1ca293df 100644
--- a/gdb/common/string_view.h
+++ b/gdb/common/string_view.h
@@ -1,5 +1,8 @@
// Components for manipulating non-owning sequences of characters -*- C++ -*-
+// Note: This file has been stolen from the gcc repo
+// (libstdc++-v3/include/std/string_view) and has local modifications.
+
// Copyright (C) 2013-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
@@ -22,33 +25,31 @@
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
-/** @file string_view
- * This is a Standard C++ Library header.
- */
//
// N3762 basic_string_view library
//
-#ifndef _GLIBCXX_STRING_VIEW
-#define _GLIBCXX_STRING_VIEW 1
-
-#pragma GCC system_header
+#ifndef STRING_VIEW_H
+#define STRING_VIEW_H 1
#if __cplusplus >= 201703L
+#include <string_view>
+
+namespace gdb {
+ using string_view = std::string_view;
+} /* namespace gdb */
+
+#else /* __cplusplus < 201703L */
+
#include <limits>
#include <iosfwd>
#include <bits/char_traits.h>
#include <bits/functional_hash.h>
#include <bits/range_access.h>
-namespace std _GLIBCXX_VISIBILITY(default)
-{
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-
-#define __cpp_lib_string_view 201603
-
+namespace gdb {
/**
* @class basic_string_view <string_view>
* @brief A non-owning reference to a string.
@@ -96,7 +97,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr basic_string_view(const basic_string_view&) noexcept = default;
- constexpr basic_string_view(const _CharT* __str) noexcept
+ basic_string_view(const _CharT* __str) noexcept
: _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
_M_str{__str}
{ }
@@ -106,7 +107,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_len{__len}, _M_str{__str}
{ }
- constexpr basic_string_view&
+ constexpr
+ basic_string_view(const std::string &__str) noexcept
+ : _M_len{__str.length()}, _M_str{__str.c_str()}
+ { }
+
+ basic_string_view&
operator=(const basic_string_view&) noexcept = default;
// [string.view.iterators], iterators
@@ -160,7 +166,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/ sizeof(value_type) / 4;
}
- [[nodiscard]] constexpr bool
+ constexpr bool
empty() const noexcept
{ return this->_M_len == 0; }
@@ -174,13 +180,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return *(this->_M_str + __pos);
}
- constexpr const _CharT&
+ const _CharT&
at(size_type __pos) const
{
if (__pos >= _M_len)
- __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
- "(which is %zu) >= this->size() "
- "(which is %zu)"), __pos, this->size());
+ error (_("basic_string_view::at: __pos "
+ "(which is %zu) >= this->size() "
+ "(which is %zu)"), __pos, this->size());
return *(this->_M_str + __pos);
}
@@ -206,7 +212,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// [string.view.modifiers], modifiers:
- constexpr void
+ void
remove_prefix(size_type __n) noexcept
{
__glibcxx_assert(this->_M_len >= __n);
@@ -214,11 +220,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
this->_M_len -= __n;
}
- constexpr void
+ void
remove_suffix(size_type __n) noexcept
{ this->_M_len -= __n; }
- constexpr void
+ void
swap(basic_string_view& __sv) noexcept
{
auto __tmp = *this;
@@ -241,7 +247,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __rlen;
}
- constexpr basic_string_view
+ basic_string_view
substr(size_type __pos, size_type __n = npos) const noexcept(false)
{
__pos = _M_check(__pos, "basic_string_view::substr");
@@ -249,7 +255,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return basic_string_view{_M_str + __pos, __rlen};
}
- constexpr int
+ int
compare(basic_string_view __str) const noexcept
{
const size_type __rlen = std::min(this->_M_len, __str._M_len);
@@ -263,14 +269,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
compare(size_type __pos1, size_type __n1, basic_string_view __str) const
{ return this->substr(__pos1, __n1).compare(__str); }
- constexpr int
+ int
compare(size_type __pos1, size_type __n1,
basic_string_view __str, size_type __pos2, size_type __n2) const
{
return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
}
- constexpr int
+ int
compare(const _CharT* __str) const noexcept
{ return this->compare(basic_string_view{__str}); }
@@ -278,7 +284,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
compare(size_type __pos1, size_type __n1, const _CharT* __str) const
{ return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
- constexpr int
+ int
compare(size_type __pos1, size_type __n1,
const _CharT* __str, size_type __n2) const noexcept(false)
{
@@ -290,10 +296,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
find(basic_string_view __str, size_type __pos = 0) const noexcept
{ return this->find(__str._M_str, __pos, __str._M_len); }
- constexpr size_type
+ size_type
find(_CharT __c, size_type __pos = 0) const noexcept;
- constexpr size_type
+ size_type
find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
constexpr size_type
@@ -304,10 +310,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
rfind(basic_string_view __str, size_type __pos = npos) const noexcept
{ return this->rfind(__str._M_str, __pos, __str._M_len); }
- constexpr size_type
+ size_type
rfind(_CharT __c, size_type __pos = npos) const noexcept;
- constexpr size_type
+ size_type
rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
constexpr size_type
@@ -322,7 +328,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
find_first_of(_CharT __c, size_type __pos = 0) const noexcept
{ return this->find(__c, __pos); }
- constexpr size_type
+ size_type
find_first_of(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
constexpr size_type
@@ -338,7 +344,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
find_last_of(_CharT __c, size_type __pos=npos) const noexcept
{ return this->rfind(__c, __pos); }
- constexpr size_type
+ size_type
find_last_of(const _CharT* __str, size_type __pos,
size_type __n) const noexcept;
@@ -351,10 +357,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
size_type __pos = 0) const noexcept
{ return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
- constexpr size_type
+ size_type
find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
- constexpr size_type
+ size_type
find_first_not_of(const _CharT* __str,
size_type __pos, size_type __n) const noexcept;
@@ -370,10 +376,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
size_type __pos = npos) const noexcept
{ return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
- constexpr size_type
+ size_type
find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
- constexpr size_type
+ size_type
find_last_not_of(const _CharT* __str,
size_type __pos, size_type __n) const noexcept;
@@ -385,13 +391,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
traits_type::length(__str));
}
- constexpr size_type
+ size_type
_M_check(size_type __pos, const char* __s) const noexcept(false)
{
if (__pos > this->size())
- __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
- "this->size() (which is %zu)"),
- __s, __pos, this->size());
+ error (_("%s: __pos (which is %zu) > "
+ "this->size() (which is %zu)"),
+ __s, __pos, this->size());
return __pos;
}
@@ -405,7 +411,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
private:
- static constexpr int
+ static int
_S_compare(size_type __n1, size_type __n2) noexcept
{
const difference_type __diff = __n1 - __n2;
@@ -428,11 +434,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// argument participates in template argument deduction and the other
// argument gets implicitly converted to the deduced type. See n3766.html.
template<typename _Tp>
- using __idt = common_type_t<_Tp>;
+ using __idt = typename std::common_type<_Tp>::type;
}
template<typename _CharT, typename _Traits>
- constexpr bool
+ bool
operator==(basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.size() == __y.size() && __x.compare(__y) == 0; }
@@ -541,8 +547,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// [string.view.io], Inserters and extractors
template<typename _CharT, typename _Traits>
- inline basic_ostream<_CharT, _Traits>&
- operator<<(basic_ostream<_CharT, _Traits>& __os,
+ inline std::basic_ostream<_CharT, _Traits>&
+ operator<<(std::basic_ostream<_CharT, _Traits>& __os,
basic_string_view<_CharT,_Traits> __str)
{ return __ostream_insert(__os, __str.data(), __str.size()); }
@@ -550,13 +556,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// basic_string_view typedef names
using string_view = basic_string_view<char>;
-#ifdef _GLIBCXX_USE_WCHAR_T
- using wstring_view = basic_string_view<wchar_t>;
-#endif
-#ifdef _GLIBCXX_USE_C99_STDINT_TR1
- using u16string_view = basic_string_view<char16_t>;
- using u32string_view = basic_string_view<char32_t>;
-#endif
// [string.view.hash], hash support:
@@ -565,97 +564,32 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<>
struct hash<string_view>
- : public __hash_base<size_t, string_view>
+ : public std::__hash_base<size_t, string_view>
{
size_t
operator()(const string_view& __str) const noexcept
{ return std::_Hash_impl::hash(__str.data(), __str.length()); }
};
+} /* namespace gdb */
- template<>
- struct __is_fast_hash<hash<string_view>> : std::false_type
- { };
-
-#ifdef _GLIBCXX_USE_WCHAR_T
- template<>
- struct hash<wstring_view>
- : public __hash_base<size_t, wstring>
- {
- size_t
- operator()(const wstring_view& __s) const noexcept
- { return std::_Hash_impl::hash(__s.data(),
- __s.length() * sizeof(wchar_t)); }
- };
-
- template<>
- struct __is_fast_hash<hash<wstring_view>> : std::false_type
- { };
-#endif
-
-#ifdef _GLIBCXX_USE_C99_STDINT_TR1
- template<>
- struct hash<u16string_view>
- : public __hash_base<size_t, u16string_view>
- {
- size_t
- operator()(const u16string_view& __s) const noexcept
- { return std::_Hash_impl::hash(__s.data(),
- __s.length() * sizeof(char16_t)); }
- };
-
- template<>
- struct __is_fast_hash<hash<u16string_view>> : std::false_type
- { };
-
- template<>
- struct hash<u32string_view>
- : public __hash_base<size_t, u32string_view>
- {
- size_t
- operator()(const u32string_view& __s) const noexcept
- { return std::_Hash_impl::hash(__s.data(),
- __s.length() * sizeof(char32_t)); }
- };
-
- template<>
- struct __is_fast_hash<hash<u32string_view>> : std::false_type
- { };
-#endif
+#include "string_view.tcc"
+namespace gdb {
inline namespace literals
{
inline namespace string_view_literals
{
+#pragma GCC system_header
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wliteral-suffix"
inline constexpr basic_string_view<char>
- operator""sv(const char* __str, size_t __len) noexcept
+ operator"" sv(const char* __str, size_t __len) noexcept
{ return basic_string_view<char>{__str, __len}; }
-
-#ifdef _GLIBCXX_USE_WCHAR_T
- inline constexpr basic_string_view<wchar_t>
- operator""sv(const wchar_t* __str, size_t __len) noexcept
- { return basic_string_view<wchar_t>{__str, __len}; }
-#endif
-
-#ifdef _GLIBCXX_USE_C99_STDINT_TR1
- inline constexpr basic_string_view<char16_t>
- operator""sv(const char16_t* __str, size_t __len) noexcept
- { return basic_string_view<char16_t>{__str, __len}; }
-
- inline constexpr basic_string_view<char32_t>
- operator""sv(const char32_t* __str, size_t __len) noexcept
- { return basic_string_view<char32_t>{__str, __len}; }
-#endif
#pragma GCC diagnostic pop
} // namespace string_literals
} // namespace literals
-
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
-
-#include <bits/string_view.tcc>
+} // namespace gdb
#endif // __cplusplus <= 201402L
-#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW
+#endif /* STRING_VIEW_H */
diff --git a/gdb/common/string_view.tcc b/gdb/common/string_view.tcc
index 07ccc849dd70..c47806ba8e6e 100644
--- a/gdb/common/string_view.tcc
+++ b/gdb/common/string_view.tcc
@@ -1,5 +1,8 @@
// Components for manipulating non-owning sequences of characters -*- C++ -*-
+// Note: This file has been stolen from the gcc repo
+// (libstdc++-v3/include/bits/string_view.tcc) and has local modifications.
+
// Copyright (C) 2013-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
@@ -31,19 +34,13 @@
// N3762 basic_string_view library
//
-#ifndef _GLIBCXX_STRING_VIEW_TCC
-#define _GLIBCXX_STRING_VIEW_TCC 1
-
-#pragma GCC system_header
-
-#if __cplusplus >= 201703L
+#ifndef STRING_VIEW_TCC
+#define STRING_VIEW_TCC 1
-namespace std _GLIBCXX_VISIBILITY(default)
+namespace gdb
{
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find(const _CharT* __str, size_type __pos, size_type __n) const noexcept
{
@@ -64,7 +61,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find(_CharT __c, size_type __pos) const noexcept
{
@@ -80,7 +77,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept
{
@@ -100,7 +97,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
rfind(_CharT __c, size_type __pos) const noexcept
{
@@ -117,7 +114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_first_of(const _CharT* __str, size_type __pos,
size_type __n) const noexcept
@@ -134,7 +131,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_last_of(const _CharT* __str, size_type __pos,
size_type __n) const noexcept
@@ -156,7 +153,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_first_not_of(const _CharT* __str, size_type __pos,
size_type __n) const noexcept
@@ -169,7 +166,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_first_not_of(_CharT __c, size_type __pos) const noexcept
{
@@ -180,7 +177,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_last_not_of(const _CharT* __str, size_type __pos,
size_type __n) const noexcept
@@ -202,7 +199,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _CharT, typename _Traits>
- constexpr typename basic_string_view<_CharT, _Traits>::size_type
+ typename basic_string_view<_CharT, _Traits>::size_type
basic_string_view<_CharT, _Traits>::
find_last_not_of(_CharT __c, size_type __pos) const noexcept
{
@@ -220,10 +217,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
return npos;
}
+} // namespace gdb
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
-
-#endif // __cplusplus <= 201402L
-
-#endif // _GLIBCXX_STRING_VIEW_TCC
+#endif // STRING_VIEW_TCC
--
2.16.3
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