Reduce the number of system calls. Use readv instead of pread. Do
[deliverable/binutils-gdb.git] / gold / fileread.cc
index a39d530ab8753ed65b567a3405e0e9b32eb5da63..010c2eebbad9bac95e11ab9184defcde32a40841 100644 (file)
@@ -26,6 +26,9 @@
 #include <cerrno>
 #include <fcntl.h>
 #include <unistd.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+#include "filenames.h"
 
 #include "options.h"
 #include "dirsearch.h"
@@ -39,7 +42,15 @@ namespace gold
 File_read::View::~View()
 {
   gold_assert(!this->is_locked());
-  delete[] this->data_;
+  if (!this->mapped_)
+    delete[] this->data_;
+  else
+    {
+      if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
+        gold_warning(_("munmap failed: %s"), strerror(errno));
+
+      File_read::current_mapped_bytes -= this->size_;
+    }
 }
 
 void
@@ -63,17 +74,22 @@ File_read::View::is_locked()
 
 // Class File_read.
 
+// The File_read static variables.
+unsigned long long File_read::total_mapped_bytes;
+unsigned long long File_read::current_mapped_bytes;
+unsigned long long File_read::maximum_mapped_bytes;
+
 // The File_read class is designed to support file descriptor caching,
 // but this is not currently implemented.
 
 File_read::~File_read()
 {
-  gold_assert(this->lock_count_ == 0);
+  gold_assert(this->token_.is_writable());
   if (this->descriptor_ >= 0)
     {
       if (close(this->descriptor_) < 0)
-       fprintf(stderr, _("%s: warning: close(%s) failed: %s"),
-               program_name, this->name_.c_str(), strerror(errno));
+       gold_warning(_("close of %s failed: %s"),
+                    this->name_.c_str(), strerror(errno));
       this->descriptor_ = -1;
     }
   this->name_.clear();
@@ -83,165 +99,187 @@ File_read::~File_read()
 // Open the file.
 
 bool
-File_read::open(const std::string& name)
+File_read::open(const Task* task, const std::string& name)
 {
-  gold_assert(this->lock_count_ == 0
+  gold_assert(this->token_.is_writable()
              && this->descriptor_ < 0
              && this->name_.empty());
   this->name_ = name;
+
   this->descriptor_ = ::open(this->name_.c_str(), O_RDONLY);
-  ++this->lock_count_;
+
+  if (this->descriptor_ >= 0)
+    {
+      struct stat s;
+      if (::fstat(this->descriptor_, &s) < 0)
+       gold_error(_("%s: fstat failed: %s"),
+                  this->name_.c_str(), strerror(errno));
+      this->size_ = s.st_size;
+    }
+
+  this->token_.add_writer(task);
+
   return this->descriptor_ >= 0;
 }
 
 // Open the file for testing purposes.
 
 bool
-File_read::open(const std::string& name, const unsigned char* contents,
-               off_t contents_size)
+File_read::open(const Task* task, const std::string& name,
+               const unsigned char* contents, off_t size)
 {
-  gold_assert(this->lock_count_ == 0
+  gold_assert(this->token_.is_writable()
              && this->descriptor_ < 0
              && this->name_.empty());
   this->name_ = name;
   this->contents_ = contents;
-  this->contents_size_ = contents_size;
-  ++this->lock_count_;
+  this->size_ = size;
+  this->token_.add_writer(task);
   return true;
 }
 
+// Release the file.  This is called when we are done with the file in
+// a Task.
+
 void
-File_read::lock()
+File_read::release()
 {
-  ++this->lock_count_;
+  gold_assert(this->is_locked());
+
+  File_read::total_mapped_bytes += this->mapped_bytes_;
+  File_read::current_mapped_bytes += this->mapped_bytes_;
+  this->mapped_bytes_ = 0;
+  if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
+    File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
+
+  this->clear_views(false);
+
+  this->released_ = true;
+}
+
+// Lock the file.
+
+void
+File_read::lock(const Task* task)
+{
+  gold_assert(this->released_);
+  this->token_.add_writer(task);
+  this->released_ = false;
 }
 
+// Unlock the file.
+
 void
-File_read::unlock()
+File_read::unlock(const Task* task)
 {
-  gold_assert(this->lock_count_ > 0);
-  --this->lock_count_;
+  this->release();
+  this->token_.remove_writer(task);
 }
 
+// Return whether the file is locked.
+
 bool
-File_read::is_locked()
+File_read::is_locked() const
 {
-  return this->lock_count_ > 0;
+  if (!this->token_.is_writable())
+    return true;
+  // The file is not locked, so it should have been released.
+  gold_assert(this->released_);
+  return false;
 }
 
 // See if we have a view which covers the file starting at START for
 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
 
 inline File_read::View*
-File_read::find_view(off_t start, off_t size)
+File_read::find_view(off_t start, section_size_type size) const
 {
   off_t page = File_read::page_offset(start);
-  Views::iterator p = this->views_.find(page);
-  if (p == this->views_.end())
-    return NULL;
-  if (p->second->size() - (start - page) < size)
+
+  Views::const_iterator p = this->views_.lower_bound(page);
+  if (p == this->views_.end() || p->first > page)
+    {
+      if (p == this->views_.begin())
+       return NULL;
+      --p;
+    }
+
+  if (p->second->start() + static_cast<off_t>(p->second->size())
+      < start + static_cast<off_t>(size))
     return NULL;
+
+  p->second->set_accessed();
+
   return p->second;
 }
 
-// Read data from the file.  Return the number of bytes read.  If
-// PBYTES is not NULL, store the number of bytes in *PBYTES, otherwise
-// require that we read exactly the number of bytes requested.
+// Read SIZE bytes from the file starting at offset START.  Read into
+// the buffer at P.
 
-off_t
-File_read::do_read(off_t start, off_t size, void* p, off_t* pbytes)
+void
+File_read::do_read(off_t start, section_size_type size, void* p) const
 {
-  gold_assert(this->lock_count_ > 0);
-
-  off_t bytes;
-  if (this->contents_ == NULL)
+  ssize_t bytes;
+  if (this->contents_ != NULL)
     {
-      int o = this->descriptor_;
-
-      if (lseek(o, start, SEEK_SET) < 0)
+      bytes = this->size_ - start;
+      if (static_cast<section_size_type>(bytes) >= size)
        {
-         fprintf(stderr, _("%s: %s: lseek to %lld failed: %s"),
-                 program_name, this->filename().c_str(),
-                 static_cast<long long>(start),
-                 strerror(errno));
-         gold_exit(false);
-       }
-
-      bytes = ::read(o, p, size);
-      if (bytes < 0)
-       {
-         fprintf(stderr, _("%s: %s: read failed: %s\n"),
-                 program_name, this->filename().c_str(), strerror(errno));
-         gold_exit(false);
+         memcpy(p, this->contents_ + start, size);
+         return;
        }
     }
   else
     {
-      bytes = this->contents_size_ - start;
-      if (bytes < 0)
-       bytes = 0;
-      else if (bytes > size)
-       bytes = size;
-      memcpy(p, this->contents_ + start, bytes);
-    }
+      bytes = ::pread(this->descriptor_, p, size, start);
+      if (static_cast<section_size_type>(bytes) == size)
+       return;
 
-  if (pbytes != NULL)
-    *pbytes = bytes;
-  else if (bytes != size)
-    {
-      fprintf(stderr,
-             _("%s: %s: file too short: read only %lld of %lld "
-               "bytes at %lld\n"),
-             program_name, this->filename().c_str(),
-             static_cast<long long>(bytes),
-             static_cast<long long>(size),
-             static_cast<long long>(start));
-      gold_exit(false);
+      if (bytes < 0)
+       {
+         gold_fatal(_("%s: pread failed: %s"),
+                    this->filename().c_str(), strerror(errno));
+         return;
+       }
     }
 
-  return bytes;
+  gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
+            this->filename().c_str(),
+            static_cast<long long>(bytes),
+            static_cast<long long>(size),
+            static_cast<long long>(start));
 }
 
 // Read data from the file.
 
 void
-File_read::read(off_t start, off_t size, void* p)
+File_read::read(off_t start, section_size_type size, void* p) const
 {
-  gold_assert(this->lock_count_ > 0);
-
-  File_read::View* pv = this->find_view(start, size);
+  const File_read::View* pv = this->find_view(start, size);
   if (pv != NULL)
     {
       memcpy(p, pv->data() + (start - pv->start()), size);
       return;
     }
 
-  this->do_read(start, size, p, NULL);
-}
-
-void
-File_read::read_up_to(off_t start, off_t size, void* p, off_t* pbytes)
-{
-  gold_assert(this->lock_count_ > 0);
-
-  File_read::View* pv = this->find_view(start, size);
-  if (pv != NULL)
-    {
-      memcpy(p, pv->data() + (start - pv->start()), size);
-      if (pbytes != NULL)
-       *pbytes = size;
-      return;
-    }
-
-  this->do_read(start, size, p, pbytes);
+  this->do_read(start, size, p);
 }
 
 // Find an existing view or make a new one.
 
 File_read::View*
-File_read::find_or_make_view(off_t start, off_t size, off_t* pbytes)
+File_read::find_or_make_view(off_t start, section_size_type size, bool cache)
 {
-  gold_assert(this->lock_count_ > 0);
+  gold_assert(!this->token_.is_writable());
+  this->released_ = false;
+
+  File_read::View* v = this->find_view(start, size);
+  if (v != NULL)
+    {
+      if (cache)
+       v->set_cache();
+      return v;
+    }
 
   off_t poff = File_read::page_offset(start);
 
@@ -251,117 +289,273 @@ File_read::find_or_make_view(off_t start, off_t size, off_t* pbytes)
 
   if (!ins.second)
     {
-      // There was an existing view at this offset.
-      File_read::View* v = ins.first->second;
-      if (v->size() - (start - v->start()) >= size)
-       {
-         if (pbytes != NULL)
-           *pbytes = size;
-         return v;
-       }
-
-      // This view is not large enough.
+      // There was an existing view at this offset.  It must not be
+      // large enough.  We can't delete it here, since something might
+      // be using it; put it on a list to be deleted when the file is
+      // unlocked.
+      v = ins.first->second;
+      gold_assert(v->size() - (start - v->start()) < size);
+      if (v->should_cache())
+       cache = true;
+      v->clear_cache();
       this->saved_views_.push_back(v);
     }
 
-  // We need to read data from the file.
-
-  off_t psize = File_read::pages(size + (start - poff));
-  unsigned char* p = new unsigned char[psize];
+  // We need to map data from the file.
 
-  off_t got_bytes;
-  off_t bytes = this->do_read(poff, psize, p, &got_bytes);
+  section_size_type psize = File_read::pages(size + (start - poff));
 
-  File_read::View* v = new File_read::View(poff, bytes, p);
-
-  ins.first->second = v;
-
-  if (bytes - (start - poff) >= size)
+  if (poff + static_cast<off_t>(psize) >= this->size_)
     {
-      if (pbytes != NULL)
-       *pbytes = size;
-      return v;
+      psize = this->size_ - poff;
+      gold_assert(psize >= size);
     }
 
-  if (pbytes != NULL)
+  if (this->contents_ != NULL)
     {
-      *pbytes = bytes - (start - poff);
-      return v;
+      unsigned char* p = new unsigned char[psize];
+      this->do_read(poff, psize, p);
+      v = new File_read::View(poff, psize, p, cache, false);
+    }
+  else
+    {
+      void* p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE,
+                       this->descriptor_, poff);
+      if (p == MAP_FAILED)
+       gold_fatal(_("%s: mmap offset %lld size %lld failed: %s"),
+                  this->filename().c_str(),
+                  static_cast<long long>(poff),
+                  static_cast<long long>(psize),
+                  strerror(errno));
+
+      this->mapped_bytes_ += psize;
+
+      const unsigned char* pbytes = static_cast<const unsigned char*>(p);
+      v = new File_read::View(poff, psize, pbytes, cache, true);
     }
 
-  fprintf(stderr,
-         _("%s: %s: file too short: read only %lld of %lld bytes at %lld\n"),
-         program_name, this->filename().c_str(),
-         static_cast<long long>(bytes - (start - poff)),
-         static_cast<long long>(size),
-         static_cast<long long>(start));
-  gold_exit(false);
+  ins.first->second = v;
+  return v;
 }
 
-// This implementation of get_view just reads into a memory buffer,
-// which we store on view_list_.  At some point we should support
-// mmap.
-
-const unsigned char*
-File_read::get_view(off_t start, off_t size)
-{
-  gold_assert(this->lock_count_ > 0);
-  File_read::View* pv = this->find_or_make_view(start, size, NULL);
-  return pv->data() + (start - pv->start());
-}
+// Get a view into the file.
 
 const unsigned char*
-File_read::get_view_and_size(off_t start, off_t size, off_t* pbytes)
+File_read::get_view(off_t start, section_size_type size, bool cache)
 {
-  gold_assert(this->lock_count_ > 0);
-  File_read::View* pv = this->find_or_make_view(start, size, pbytes);
+  File_read::View* pv = this->find_or_make_view(start, size, cache);
   return pv->data() + (start - pv->start());
 }
 
 File_view*
-File_read::get_lasting_view(off_t start, off_t size)
+File_read::get_lasting_view(off_t start, section_size_type size, bool cache)
 {
-  gold_assert(this->lock_count_ > 0);
-  File_read::View* pv = this->find_or_make_view(start, size, NULL);
+  File_read::View* pv = this->find_or_make_view(start, size, cache);
   pv->lock();
   return new File_view(*this, pv, pv->data() + (start - pv->start()));
 }
 
-// Remove all the file views.
+// Use readv to read COUNT entries from RM starting at START.  BASE
+// must be added to all file offsets in RM.
 
 void
-File_read::clear_views(bool destroying)
+File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
+                   size_t count)
+{
+  unsigned char discard[File_read::page_size];
+  iovec iov[File_read::max_readv_entries * 2];
+  size_t iov_index = 0;
+
+  off_t first_offset = rm[start].file_offset;
+  off_t last_offset = first_offset;
+  ssize_t want = 0;
+  for (size_t i = 0; i < count; ++i)
+    {
+      const Read_multiple_entry& i_entry(rm[start + i]);
+
+      if (i_entry.file_offset > last_offset)
+       {
+         size_t skip = i_entry.file_offset - last_offset;
+         gold_assert(skip <= sizeof discard);
+
+         iov[iov_index].iov_base = discard;
+         iov[iov_index].iov_len = skip;
+         ++iov_index;
+
+         want += skip;
+       }
+
+      iov[iov_index].iov_base = i_entry.buffer;
+      iov[iov_index].iov_len = i_entry.size;
+      ++iov_index;
+
+      want += i_entry.size;
+
+      last_offset = i_entry.file_offset + i_entry.size;
+    }
+
+  gold_assert(iov_index < sizeof iov / sizeof iov[0]);
+
+  if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
+    gold_fatal(_("%s: lseek failed: %s"),
+              this->filename().c_str(), strerror(errno));
+
+  ssize_t got = ::readv(this->descriptor_, iov, iov_index);
+
+  if (got < 0)
+    gold_fatal(_("%s: readv failed: %s"),
+              this->filename().c_str(), strerror(errno));
+  if (got != want)
+    gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
+              this->filename().c_str(),
+              got, want, static_cast<long long>(base + first_offset));
+}
+
+// Read several pieces of data from the file.
+
+void
+File_read::read_multiple(off_t base, const Read_multiple& rm)
 {
+  size_t count = rm.size();
+  size_t i = 0;
+  while (i < count)
+    {
+      // Find up to MAX_READV_ENTRIES consecutive entries which are
+      // less than one page apart.
+      const Read_multiple_entry& i_entry(rm[i]);
+      off_t i_off = i_entry.file_offset;
+      off_t end_off = i_off + i_entry.size;
+      size_t j;
+      for (j = i + 1; j < count; ++j)
+       {
+         if (j - i >= File_read::max_readv_entries)
+           break;
+         const Read_multiple_entry& j_entry(rm[j]);
+         off_t j_off = j_entry.file_offset;
+         gold_assert(j_off >= end_off);
+         off_t j_end_off = j_off + j_entry.size;
+         if (j_end_off - end_off >= File_read::page_size)
+           break;
+         end_off = j_end_off;
+       }
+
+      if (j == i + 1)
+       this->read(base + i_off, i_entry.size, i_entry.buffer);
+      else
+       {
+         File_read::View* view = this->find_view(base + i_off,
+                                                 end_off - i_off);
+         if (view == NULL)
+           this->do_readv(base, rm, i, j - i);
+         else
+           {
+             const unsigned char* v = (view->data()
+                                       + (base + i_off - view->start()));
+             for (size_t k = i; k < j; ++k)
+               {
+                 const Read_multiple_entry& k_entry(rm[k]);
+                 gold_assert(k_entry.file_offset - i_off + k_entry.size
+                             <= end_off - i_off);
+                 memcpy(k_entry.buffer,
+                        v + (k_entry.file_offset - i_off),
+                        k_entry.size);
+               }
+           }
+       }
+
+      i = j;
+    }
+}
+
+// Mark all views as no longer cached.
+
+void
+File_read::clear_view_cache_marks()
+{
+  // Just ignore this if there are multiple objects associated with
+  // the file.  Otherwise we will wind up uncaching and freeing some
+  // views for other objects.
+  if (this->object_count_ > 1)
+    return;
+
   for (Views::iterator p = this->views_.begin();
        p != this->views_.end();
        ++p)
+    p->second->clear_cache();
+  for (Saved_views::iterator p = this->saved_views_.begin();
+       p != this->saved_views_.end();
+       ++p)
+    (*p)->clear_cache();
+}
+
+// Remove all the file views.  For a file which has multiple
+// associated objects (i.e., an archive), we keep accessed views
+// around until next time, in the hopes that they will be useful for
+// the next object.
+
+void
+File_read::clear_views(bool destroying)
+{
+  Views::iterator p = this->views_.begin();
+  while (p != this->views_.end())
     {
-      if (!p->second->is_locked())
-       delete p->second;
+      bool should_delete;
+      if (p->second->is_locked())
+       should_delete = false;
+      else if (destroying)
+       should_delete = true;
+      else if (p->second->should_cache())
+       should_delete = false;
+      else if (this->object_count_ > 1 && p->second->accessed())
+       should_delete = false;
+      else
+       should_delete = true;
+
+      if (should_delete)
+       {
+         delete p->second;
+
+         // map::erase invalidates only the iterator to the deleted
+         // element.
+         Views::iterator pe = p;
+         ++p;
+         this->views_.erase(pe);
+       }
       else
        {
          gold_assert(!destroying);
-         this->saved_views_.push_back(p->second);
+         p->second->clear_accessed();
+         ++p;
        }
     }
-  this->views_.clear();
 
-  Saved_views::iterator p = this->saved_views_.begin();
-  while (p != this->saved_views_.end())
+  Saved_views::iterator q = this->saved_views_.begin();
+  while (q != this->saved_views_.end())
     {
-      if (!(*p)->is_locked())
+      if (!(*q)->is_locked())
        {
-         delete *p;
-         p = this->saved_views_.erase(p);
+         delete *q;
+         q = this->saved_views_.erase(q);
        }
       else
        {
          gold_assert(!destroying);
-         ++p;
+         ++q;
        }
     }
 }
 
+// Print statistical information to stderr.  This is used for --stats.
+
+void
+File_read::print_stats()
+{
+  fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
+         program_name, File_read::total_mapped_bytes);
+  fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
+         program_name, File_read::maximum_mapped_bytes);
+}
+
 // Class File_view.
 
 File_view::~File_view()
@@ -374,51 +568,104 @@ File_view::~File_view()
 
 // Create a file for testing.
 
-Input_file::Input_file(const char* name, const unsigned char* contents,
-                      off_t size)
+Input_file::Input_file(const Task* task, const char* name,
+                      const unsigned char* contents, off_t size)
   : file_()
 {
   this->input_argument_ =
-    new Input_file_argument(name, false, Position_dependent_options());
-  bool ok = file_.open(name, contents, size);
+    new Input_file_argument(name, false, "", Position_dependent_options());
+  bool ok = file_.open(task, name, contents, size);
   gold_assert(ok);
 }
 
 // Open the file.
 
-void
-Input_file::open(const General_options& options, const Dirsearch& dirpath)
+// If the filename is not absolute, we assume it is in the current
+// directory *except* when:
+//    A) input_argument_->is_lib() is true; or
+//    B) input_argument_->extra_search_path() is not empty.
+// In both cases, we look in extra_search_path + library_path to find
+// the file location, rather than the current directory.
+
+bool
+Input_file::open(const General_options& options, const Dirsearch& dirpath,
+                const Task* task)
 {
   std::string name;
-  if (!this->input_argument_->is_lib())
-    name = this->input_argument_->name();
-  else
+
+  // Case 1: name is an absolute file, just try to open it
+  // Case 2: name is relative but is_lib is false and extra_search_path
+  //         is empty
+  if (IS_ABSOLUTE_PATH (this->input_argument_->name())
+      || (!this->input_argument_->is_lib()
+         && this->input_argument_->extra_search_path() == NULL))
+    {
+      name = this->input_argument_->name();
+      this->found_name_ = name;
+    }
+  // Case 3: is_lib is true
+  else if (this->input_argument_->is_lib())
     {
+      // We don't yet support extra_search_path with -l.
+      gold_assert(this->input_argument_->extra_search_path() == NULL);
       std::string n1("lib");
       n1 += this->input_argument_->name();
       std::string n2;
-      if (options.is_static())
+      if (options.is_static()
+         || this->input_argument_->options().do_static_search())
        n1 += ".a";
       else
        {
          n2 = n1 + ".a";
          n1 += ".so";
        }
-      name = dirpath.find(n1, n2);
+      name = dirpath.find(n1, n2, &this->is_in_sysroot_);
       if (name.empty())
        {
-         fprintf(stderr, _("%s: cannot find %s\n"), program_name,
-                 this->input_argument_->name());
-         gold_exit(false);
+         gold_error(_("cannot find -l%s"),
+                    this->input_argument_->name());
+         return false;
        }
+      if (n2.empty() || name[name.length() - 1] == 'o')
+       this->found_name_ = n1;
+      else
+       this->found_name_ = n2;
+    }
+  // Case 4: extra_search_path is not empty
+  else
+    {
+      gold_assert(this->input_argument_->extra_search_path() != NULL);
+
+      // First, check extra_search_path.
+      name = this->input_argument_->extra_search_path();
+      if (!IS_DIR_SEPARATOR (name[name.length() - 1]))
+        name += '/';
+      name += this->input_argument_->name();
+      struct stat dummy_stat;
+      if (::stat(name.c_str(), &dummy_stat) < 0)
+        {
+          // extra_search_path failed, so check the normal search-path.
+          name = dirpath.find(this->input_argument_->name(), "",
+                             &this->is_in_sysroot_);
+          if (name.empty())
+            {
+              gold_error(_("cannot find %s"),
+                        this->input_argument_->name());
+             return false;
+            }
+        }
+      this->found_name_ = this->input_argument_->name();
     }
 
-  if (!this->file_.open(name))
+  // Now that we've figured out where the file lives, try to open it.
+  if (!this->file_.open(task, name))
     {
-      fprintf(stderr, _("%s: cannot open %s: %s\n"), program_name,
-             name.c_str(), strerror(errno));
-      gold_exit(false);
+      gold_error(_("cannot open %s: %s"),
+                name.c_str(), strerror(errno));
+      return false;
     }
+
+  return true;
 }
 
 } // End namespace gold.
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