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llvm-project/libcxx/src/debug.cpp
Howard Hinnant 42a3046eef Ok, 3 major changes for debug mode in one commit: 
1.  I had been detecting and trapping iterator == and \!= among iterators
    in different containers as an error.  But the trapping itself is actually
    an error.
    
    Consider:
    
    #include <iostream>
    #include <vector>
    #include <algorithm>

    template <class C>
    void
    display(const C& c)
    {
        std::cout << "{";
        bool first = true;
        for (const auto& x : c)
        {
            if (\!first)
                std::cout << ", ";
            first = false;
            std::cout << x;
        }
        std::cout << "}\n";
    }

    int
    main()
    {
        typedef std::vector<int> V;
        V v1 = {1, 3, 5};
        V v2 = {2, 4, 6};
        display(v1);
        display(v2);
        V::iterator i = std::find(v1.begin(), v1.end(), 1);
        V::iterator j = std::find(v2.begin(), v2.end(), 2);
        if (*i == *j)
            i = j;    // perfectly legal
        // ...
        if (i \!= j)   // the only way to check
            v2.push_back(*i);
        display(v1);
        display(v2);
    }

    It is legal to assign an iterator from one container to another of the
    same type.  This is required to work.  One might want to test whether or
    not such an assignment had been made.  The way one performs such a check
    is using the iterator's ==, \!= operator.  This is a logical and necessary
    function and does not constitute an error.

2.  I had a header circular dependence bug when _LIBCPP_DEBUG2 is defined.
    This caused a problem in several of the libc++ tests.
    Fixed.

3.  There is a serious problem when _LIBCPP_DEBUG2=1 at the moment in that
    std::basic_string is inoperable.  std::basic_string uses __wrap_iterator
    to implement its iterators.  __wrap_iterator has been rigged up in debug
    mode to support vector.  But string hasn't been rigged up yet.  This means
    that one gets false positives when using std::string in debug mode.  I've
    upped std::string's priority in www/debug_mode.html.

llvm-svn: 187636
2013-08-02 00:26:35 +00:00

507 lines
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//===-------------------------- debug.cpp ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#define _LIBCPP_DEBUG2 1
#include "__config"
#include "__debug"
#include "functional"
#include "algorithm"
#include "__hash_table"
#include "mutex"
_LIBCPP_BEGIN_NAMESPACE_STD
_LIBCPP_FUNC_VIS
__libcpp_db*
__get_db()
{
static __libcpp_db db;
return &db;
}
_LIBCPP_FUNC_VIS
const __libcpp_db*
__get_const_db()
{
return __get_db();
}
namespace
{
typedef mutex mutex_type;
typedef lock_guard<mutex_type> WLock;
typedef lock_guard<mutex_type> RLock;
mutex_type&
mut()
{
static mutex_type m;
return m;
}
} // unnamed namespace
__i_node::~__i_node()
{
if (__next_)
{
__next_->~__i_node();
free(__next_);
}
}
__c_node::~__c_node()
{
free(beg_);
if (__next_)
{
__next_->~__c_node();
free(__next_);
}
}
__libcpp_db::__libcpp_db()
: __cbeg_(nullptr),
__cend_(nullptr),
__csz_(0),
__ibeg_(nullptr),
__iend_(nullptr),
__isz_(0)
{
}
__libcpp_db::~__libcpp_db()
{
if (__cbeg_)
{
for (__c_node** p = __cbeg_; p != __cend_; ++p)
{
if (*p != nullptr)
{
(*p)->~__c_node();
free(*p);
}
}
free(__cbeg_);
}
if (__ibeg_)
{
for (__i_node** p = __ibeg_; p != __iend_; ++p)
{
if (*p != nullptr)
{
(*p)->~__i_node();
free(*p);
}
}
free(__ibeg_);
}
}
void*
__libcpp_db::__find_c_from_i(void* __i) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
_LIBCPP_ASSERT(i != nullptr, "iterator not found in debug database.");
return i->__c_ != nullptr ? i->__c_->__c_ : nullptr;
}
void
__libcpp_db::__insert_ic(void* __i, const void* __c)
{
WLock _(mut());
__i_node* i = __insert_iterator(__i);
const char* errmsg =
"Container constructed in a translation unit with debug mode disabled."
" But it is being used in a translation unit with debug mode enabled."
" Enable it in the other translation unit with #define _LIBCPP_DEBUG2 1";
_LIBCPP_ASSERT(__cbeg_ != __cend_, errmsg);
size_t hc = hash<const void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* c = __cbeg_[hc];
_LIBCPP_ASSERT(c != nullptr, errmsg);
while (c->__c_ != __c)
{
c = c->__next_;
_LIBCPP_ASSERT(c != nullptr, errmsg);
}
c->__add(i);
i->__c_ = c;
}
__c_node*
__libcpp_db::__insert_c(void* __c)
{
WLock _(mut());
if (__csz_ + 1 > static_cast<size_t>(__cend_ - __cbeg_))
{
size_t nc = __next_prime(2*static_cast<size_t>(__cend_ - __cbeg_) + 1);
__c_node** cbeg = static_cast<__c_node**>(calloc(nc, sizeof(void*)));
if (cbeg == nullptr)
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_alloc();
#else
abort();
#endif
for (__c_node** p = __cbeg_; p != __cend_; ++p)
{
__c_node* q = *p;
while (q != nullptr)
{
size_t h = hash<void*>()(q->__c_) % nc;
__c_node* r = q->__next_;
q->__next_ = cbeg[h];
cbeg[h] = q;
q = r;
}
}
free(__cbeg_);
__cbeg_ = cbeg;
__cend_ = __cbeg_ + nc;
}
size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p = __cbeg_[hc];
__c_node* r = __cbeg_[hc] =
static_cast<__c_node*>(malloc(sizeof(__c_node)));
if (__cbeg_[hc] == nullptr)
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_alloc();
#else
abort();
#endif
r->__c_ = __c;
r->__next_ = p;
++__csz_;
return r;
}
void
__libcpp_db::__erase_i(void* __i)
{
WLock _(mut());
if (__ibeg_ != __iend_)
{
size_t hi = hash<void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
__i_node* p = __ibeg_[hi];
if (p != nullptr)
{
__i_node* q = nullptr;
while (p->__i_ != __i)
{
q = p;
p = p->__next_;
if (p == nullptr)
return;
}
if (q == nullptr)
__ibeg_[hi] = p->__next_;
else
q->__next_ = p->__next_;
__c_node* c = p->__c_;
free(p);
--__isz_;
if (c != nullptr)
c->__remove(p);
}
}
}
void
__libcpp_db::__invalidate_all(void* __c)
{
WLock _(mut());
size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p = __cbeg_[hc];
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __invalidate_all A");
while (p->__c_ != __c)
{
p = p->__next_;
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __invalidate_all B");
}
while (p->end_ != p->beg_)
{
--p->end_;
(*p->end_)->__c_ = nullptr;
}
}
__c_node*
__libcpp_db::__find_c_and_lock(void* __c) const
{
mut().lock();
size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p = __cbeg_[hc];
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c_and_lock A");
while (p->__c_ != __c)
{
p = p->__next_;
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c_and_lock B");
}
return p;
}
__c_node*
__libcpp_db::__find_c(void* __c) const
{
size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p = __cbeg_[hc];
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c A");
while (p->__c_ != __c)
{
p = p->__next_;
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c B");
}
return p;
}
void
__libcpp_db::unlock() const
{
mut().unlock();
}
void
__libcpp_db::__erase_c(void* __c)
{
WLock _(mut());
size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p = __cbeg_[hc];
__c_node* q = nullptr;
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __erase_c A");
while (p->__c_ != __c)
{
q = p;
p = p->__next_;
_LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __erase_c B");
}
if (q == nullptr)
__cbeg_[hc] = p->__next_;
else
q->__next_ = p->__next_;
while (p->end_ != p->beg_)
{
--p->end_;
(*p->end_)->__c_ = nullptr;
}
free(p->beg_);
free(p);
--__csz_;
}
void
__libcpp_db::__iterator_copy(void* __i, const void* __i0)
{
WLock _(mut());
__i_node* i = __find_iterator(__i);
__i_node* i0 = __find_iterator(__i0);
__c_node* c0 = i0 != nullptr ? i0->__c_ : nullptr;
if (i == nullptr && i0 != nullptr)
i = __insert_iterator(__i);
__c_node* c = i != nullptr ? i->__c_ : nullptr;
if (c != c0)
{
if (c != nullptr)
c->__remove(i);
if (i != nullptr)
{
i->__c_ = nullptr;
if (c0 != nullptr)
{
i->__c_ = c0;
i->__c_->__add(i);
}
}
}
}
bool
__libcpp_db::__dereferenceable(const void* __i) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
return i != nullptr && i->__c_ != nullptr && i->__c_->__dereferenceable(__i);
}
bool
__libcpp_db::__decrementable(const void* __i) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
return i != nullptr && i->__c_ != nullptr && i->__c_->__decrementable(__i);
}
bool
__libcpp_db::__addable(const void* __i, ptrdiff_t __n) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
return i != nullptr && i->__c_ != nullptr && i->__c_->__addable(__i, __n);
}
bool
__libcpp_db::__subscriptable(const void* __i, ptrdiff_t __n) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
return i != nullptr && i->__c_ != nullptr && i->__c_->__subscriptable(__i, __n);
}
bool
__libcpp_db::__less_than_comparable(const void* __i, const void* __j) const
{
RLock _(mut());
__i_node* i = __find_iterator(__i);
__i_node* j = __find_iterator(__j);
__c_node* ci = i != nullptr ? i->__c_ : nullptr;
__c_node* cj = j != nullptr ? j->__c_ : nullptr;
return ci != nullptr && ci == cj;
}
void
__libcpp_db::swap(void* c1, void* c2)
{
WLock _(mut());
size_t hc = hash<void*>()(c1) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p1 = __cbeg_[hc];
_LIBCPP_ASSERT(p1 != nullptr, "debug mode internal logic error swap A");
while (p1->__c_ != c1)
{
p1 = p1->__next_;
_LIBCPP_ASSERT(p1 != nullptr, "debug mode internal logic error swap B");
}
hc = hash<void*>()(c2) % static_cast<size_t>(__cend_ - __cbeg_);
__c_node* p2 = __cbeg_[hc];
_LIBCPP_ASSERT(p2 != nullptr, "debug mode internal logic error swap C");
while (p2->__c_ != c2)
{
p2 = p2->__next_;
_LIBCPP_ASSERT(p2 != nullptr, "debug mode internal logic error swap D");
}
std::swap(p1->beg_, p2->beg_);
std::swap(p1->end_, p2->end_);
std::swap(p1->cap_, p2->cap_);
for (__i_node** p = p1->beg_; p != p1->end_; ++p)
(*p)->__c_ = p1;
for (__i_node** p = p2->beg_; p != p2->end_; ++p)
(*p)->__c_ = p2;
}
void
__libcpp_db::__insert_i(void* __i)
{
WLock _(mut());
__insert_iterator(__i);
}
void
__c_node::__add(__i_node* i)
{
if (end_ == cap_)
{
size_t nc = 2*static_cast<size_t>(cap_ - beg_);
if (nc == 0)
nc = 1;
__i_node** beg =
static_cast<__i_node**>(malloc(nc * sizeof(__i_node*)));
if (beg == nullptr)
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_alloc();
#else
abort();
#endif
if (nc > 1)
memcpy(beg, beg_, nc/2*sizeof(__i_node*));
free(beg_);
beg_ = beg;
end_ = beg_ + nc/2;
cap_ = beg_ + nc;
}
*end_++ = i;
}
// private api
_LIBCPP_HIDDEN
__i_node*
__libcpp_db::__insert_iterator(void* __i)
{
if (__isz_ + 1 > static_cast<size_t>(__iend_ - __ibeg_))
{
size_t nc = __next_prime(2*static_cast<size_t>(__iend_ - __ibeg_) + 1);
__i_node** ibeg = static_cast<__i_node**>(calloc(nc, sizeof(void*)));
if (ibeg == nullptr)
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_alloc();
#else
abort();
#endif
for (__i_node** p = __ibeg_; p != __iend_; ++p)
{
__i_node* q = *p;
while (q != nullptr)
{
size_t h = hash<void*>()(q->__i_) % nc;
__i_node* r = q->__next_;
q->__next_ = ibeg[h];
ibeg[h] = q;
q = r;
}
}
free(__ibeg_);
__ibeg_ = ibeg;
__iend_ = __ibeg_ + nc;
}
size_t hi = hash<void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
__i_node* p = __ibeg_[hi];
__i_node* r = __ibeg_[hi] =
static_cast<__i_node*>(malloc(sizeof(__i_node)));
if (r == nullptr)
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_alloc();
#else
abort();
#endif
::new(r) __i_node(__i, p, nullptr);
++__isz_;
return r;
}
_LIBCPP_HIDDEN
__i_node*
__libcpp_db::__find_iterator(const void* __i) const
{
__i_node* r = nullptr;
if (__ibeg_ != __iend_)
{
size_t h = hash<const void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
for (__i_node* nd = __ibeg_[h]; nd != nullptr; nd = nd->__next_)
{
if (nd->__i_ == __i)
{
r = nd;
break;
}
}
}
return r;
}
_LIBCPP_HIDDEN
void
__c_node::__remove(__i_node* p)
{
__i_node** r = find(beg_, end_, p);
_LIBCPP_ASSERT(r != end_, "debug mode internal logic error __c_node::__remove");
if (--end_ != r)
memmove(r, r+1, static_cast<size_t>(end_ - r)*sizeof(__i_node*));
}
_LIBCPP_END_NAMESPACE_STD
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