Speed up direct linking with DLLs on Windows (2/2).

This patch deals with the generation of the import library on the fly.

The implementation is inefficient because the linker makes a lot of
calls to realloc and memmove when importing the symbols in order to
maintain a sorted list of symbols.

This is fixable by relying on the fact that, for every linked DLL,
the list of symbols it exports is already sorted so you can import
them en masse once you have found the insertion point.

ld/
	* deffile.h (def_file_add_import_from): Declare.
	(def_file_add_import_at): Likewise.
	* deffilep.y (fill_in_import): New function extracted from...
	(def_file_add_import): ...here.  Call it.
	(def_file_add_import_from): New function.
	(def_file_add_import_at): Likewise.
	* pe-dll.c (pe_implied_import_dll): Use an optimized version of the
	insertion loop for imported symbols if possible.

diff --git a/ld/ChangeLog b/ld/ChangeLog
index b1a1dda62b760f4dcfe84bdbfaa4422ce8f768c6..c6f85fffe65e64aed9a1040b887ffbbda4ee057f 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,14 @@
+2018-04-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * deffile.h (def_file_add_import_from): Declare.
+       (def_file_add_import_at): Likewise.
+       * deffilep.y (fill_in_import): New function extracted from...
+       (def_file_add_import): ...here.  Call it.
+       (def_file_add_import_from): New function.
+       (def_file_add_import_at): Likewise.
+       * pe-dll.c (pe_implied_import_dll): Use an optimized version of the
+       insertion loop for imported symbols if possible.
+
 2018-04-04  Eric Botcazou  <ebotcazou@adacore.com>
 
        * emultempl/pe.em (U_SIZE): Delete.

diff --git a/ld/deffile.h b/ld/deffile.h
index 9a1e539667310675010f14ffd0a2bf3c57e3cccc..4275e7143c89aa51ea0489c68c88eb8b282e4396 100644 (file)
--- a/ld/deffile.h
+++ b/ld/deffile.h
@@ -108,6 +108,16 @@ extern def_file_export *def_file_add_export (def_file *, const char *,
 extern def_file_import *def_file_add_import (def_file *, const char *,
                                             const char *, int, const char *,
                                             const char *, int *);
+extern int def_file_add_import_from (def_file *fdef,
+                                    int num_imports,
+                                    const char *name,
+                                    const char *module,
+                                    int ordinal,
+                                    const char *internal_name,
+                                    const char *its_name);
+extern def_file_import *def_file_add_import_at (def_file *, int, const char *,
+                                               const char *, int, const char *,
+                                               const char *);
 extern void def_file_add_directive (def_file *, const char *, int);
 extern def_file_module *def_get_module (def_file *, const char *);
 #ifdef DEF_FILE_PRINT

diff --git a/ld/deffilep.y b/ld/deffilep.y
index 1931c00b9e9c027f7c5e7001479ecf301e792274..1aebdf65a6ae20884bbb35c5a2e11eb57b87d65e 100644 (file)
--- a/ld/deffilep.y
+++ b/ld/deffilep.y
@@ -816,6 +816,26 @@ find_import_in_list (def_file_import *b, int max,
   return l;
 }
 
+static void
+fill_in_import (def_file_import *i,
+               const char *name,
+               def_file_module *module,
+               int ordinal,
+               const char *internal_name,
+               const char *its_name)
+{
+  memset (i, 0, sizeof (def_file_import));
+  if (name)
+    i->name = xstrdup (name);
+  i->module = module;
+  i->ordinal = ordinal;
+  if (internal_name)
+    i->internal_name = xstrdup (internal_name);
+  else
+    i->internal_name = i->name;
+  i->its_name = (its_name ? xstrdup (its_name) : NULL);
+}
+
 def_file_import *
 def_file_add_import (def_file *fdef,
                     const char *name,
@@ -850,18 +870,74 @@ def_file_add_import (def_file *fdef,
     }
   i = fdef->imports + pos;
   if (pos != fdef->num_imports)
-    memmove (&i[1], i, (sizeof (def_file_import) * (fdef->num_imports - pos)));
-  memset (i, 0, sizeof (def_file_import));
-  if (name)
-    i->name = xstrdup (name);
-  if (module)
-    i->module = def_stash_module (fdef, module);
-  i->ordinal = ordinal;
-  if (internal_name)
-    i->internal_name = xstrdup (internal_name);
-  else
-    i->internal_name = i->name;
-  i->its_name = (its_name ? xstrdup (its_name) : NULL);
+    memmove (i + 1, i, sizeof (def_file_import) * (fdef->num_imports - pos));
+
+  fill_in_import (i, name, def_stash_module (fdef, module), ordinal,
+                 internal_name, its_name);
+  fdef->num_imports++;
+
+  return i;
+}
+
+int
+def_file_add_import_from (def_file *fdef,
+                         int num_imports,
+                         const char *name,
+                         const char *module,
+                         int ordinal,
+                         const char *internal_name,
+                         const char *its_name ATTRIBUTE_UNUSED)
+{
+  def_file_import *i;
+  int is_dup;
+  int pos;
+  int max_imports = ROUND_UP (fdef->num_imports, 16);
+
+  /* We need to avoid here duplicates.  */
+  is_dup = 0;
+  pos = find_import_in_list (fdef->imports, fdef->num_imports,
+                            name, internal_name ? internal_name : name,
+                            module, ordinal, &is_dup);
+  if (is_dup != 0)
+    return -1;
+  if (fdef->imports && pos != fdef->num_imports)
+    {
+      i = fdef->imports + pos;
+      if (i->module && strcmp (i->module->name, module) == 0)
+       return -1;
+    }
+
+  if (fdef->num_imports + num_imports - 1 >= max_imports)
+    {
+      max_imports = ROUND_UP (fdef->num_imports + num_imports, 16);
+
+      if (fdef->imports)
+       fdef->imports = xrealloc (fdef->imports,
+                                max_imports * sizeof (def_file_import));
+      else
+       fdef->imports = xmalloc (max_imports * sizeof (def_file_import));
+    }
+  i = fdef->imports + pos;
+  if (pos != fdef->num_imports)
+    memmove (i + num_imports, i,
+            sizeof (def_file_import) * (fdef->num_imports - pos));
+
+  return pos;
+}
+
+def_file_import *
+def_file_add_import_at (def_file *fdef,
+                       int pos,
+                       const char *name,
+                       const char *module,
+                       int ordinal,
+                       const char *internal_name,
+                       const char *its_name)
+{
+  def_file_import *i = fdef->imports + pos;
+
+  fill_in_import (i, name, def_stash_module (fdef, module), ordinal,
+                 internal_name, its_name);
   fdef->num_imports++;
 
   return i;

diff --git a/ld/pe-dll.c b/ld/pe-dll.c
index ad0ffcffea062cbac33852f35c0ee15df38dc4fc..efb75f2e3e8ac44f32687e2bf6715da62ac09833 100644 (file)
--- a/ld/pe-dll.c
+++ b/ld/pe-dll.c
@@ -3317,6 +3317,7 @@ pe_implied_import_dll (const char *filename)
   bfd_vma rdata_end = 0;
   bfd_vma bss_start = 1;
   bfd_vma bss_end = 0;
+  int from;
 
   /* No, I can't use bfd here.  kernel32.dll puts its export table in
      the middle of the .rdata section.  */
@@ -3457,6 +3458,40 @@ pe_implied_import_dll (const char *filename)
       return TRUE;
     }
 
+  /* This is an optimized version of the insertion loop, which avoids lots of
+     calls to realloc and memmove from def_file_add_import.  */
+  if ((from = def_file_add_import_from (pe_def_file, nexp,
+                                       erva + pe_as32 (erva + name_rvas),
+                                       dllname, 0, NULL, NULL)) >= 0)
+    {
+      for (i = 0; i < nexp; i++)
+       {
+         /* Pointer to the names vector.  */
+         bfd_vma name_rva = pe_as32 (erva + name_rvas + i * 4);
+         def_file_import *imp;
+         /* Pointer to the function address vector.  */
+         bfd_vma func_rva = pe_as32 (erva + exp_funcbase + i * 4);
+         /* is_data is true if the address is in the data, rdata or bss
+            segment.  */
+         const int is_data =
+           (func_rva >= data_start && func_rva < data_end)
+           || (func_rva >= rdata_start && func_rva < rdata_end)
+           || (func_rva >= bss_start && func_rva < bss_end);
+
+         imp = def_file_add_import_at (pe_def_file, from + i, erva + name_rva,
+                                       dllname, i, NULL, NULL);
+         /* Mark symbol type.  */
+         imp->data = is_data;
+
+         if (pe_dll_extra_pe_debug)
+           printf ("%s dll-name: %s sym: %s addr: 0x%lx %s\n",
+                   __FUNCTION__, dllname, erva + name_rva,
+                   (unsigned long) func_rva, is_data ? "(data)" : "");
+       }
+
+      return TRUE;
+    }
+
   /* Iterate through the list of symbols.  */
   for (i = 0; i < nexp; i++)
     {