Allow gdb to find debug symbols file by build-id for PE file format also

This promotes BFD's struct elf_build_id to the generic struct bfd_build_id,
populated when an ELF or PE BFD is read.

gdb is updated to use that, and to use the build-id to find symbols for PE files
also.

There is currently no generic way to extract the build-id from an object file,
perhaps an option to objdump to do this might make sense?

On x86_64-pc-cygwin, gdb's sepdebug.exp changes:

-# of unsupported tests          1
+# of expected passes            90

I don't seem to get consistent testsuite runs on i686-linux-gnu, but there
don't appear to be any regressions.

bfd/ChangeLog:

2015-06-10  Jon Turney  <jon.turney@dronecode.org.uk>

	* elf-bfd.h : Remove struct elf_build_id.
	* bfd.c : Add struct bfd_build_id.
	* bfd-in2.h: Regenerate.
	* elf.c (elfobj_grok_gnu_build_id): Update to use bfd_build_id.
	* libpei.h: Add protoype and macros for
	bfd_XXi_slurp_codeview_record.
	* peXXigen.c (_bfd_XXi_slurp_codeview_record): Make public
	* peicode.h (pe_bfd_read_buildid): Add.
	(pe_bfd_object_p): Use pe_bfd_read_buildid().

gdb/ChangeLog:

2015-06-10  Jon Turney  <jon.turney@dronecode.org.uk>

	* build-id.c: Don't include elf-bfd.h.
	(build_id_bfd_get): Use bfd_build_id.
	(build_id_verify): Ditto.
	* build-id.h: Ditto.
	(find_separate_debug_file_by_buildid): Ditto.
	* python/py-objfile.c: Don't include elf-bfd.h.
	(objfpy_get_build_id) Use bfd_build_id.
	(objfpy_build_id_matches, objfpy_lookup_objfile_by_build_id): Ditto.
	* coffread.c: Include build-id.h.
	(coff_symfile_read): Try find_separate_debug_file_by_buildid.

gdb/doc/ChangeLog:

2015-06-10  Jon Turney  <jon.turney@dronecode.org.uk>

	* gdb.texinfo (Separate Debug Files): Document that PE is also
	supported.

gdb/testsuite/ChangeLog:

2015-06-10  Jon Turney  <jon.turney@dronecode.org.uk>

	* gdb.base/sepdebug.exp: Add EXEEXT where needed.
	* lib/gdb.exp (get_build_id): Teach how to extract build-id from a
	PE file.
	* lib/future.exp (gdb_find_objdump): Add gdb_find_objdump.

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>

1 files changed, 96 insertions, 4 deletions

diff --git a/bfd/peicode.h b/bfd/peicode.h
index 200ef5e..06bcaa9 100644
--- a/bfd/peicode.h
+++ b/bfd/peicode.h
@@ -1255,6 +1255,87 @@ pe_ILF_object_p (bfd * abfd)
   return abfd->xvec;
 }
 
+static void
+pe_bfd_read_buildid(bfd *abfd)
+{
+  pe_data_type *pe = pe_data (abfd);
+  struct internal_extra_pe_aouthdr *extra = &pe->pe_opthdr;
+  asection *section;
+  bfd_byte *data = 0;
+  bfd_size_type dataoff;
+  unsigned int i;
+
+  bfd_vma addr = extra->DataDirectory[PE_DEBUG_DATA].VirtualAddress;
+  bfd_size_type size = extra->DataDirectory[PE_DEBUG_DATA].Size;
+
+  if (size == 0)
+    return;
+
+  addr += extra->ImageBase;
+
+  /* Search for the section containing the DebugDirectory */
+  for (section = abfd->sections; section != NULL; section = section->next)
+    {
+      if ((addr >= section->vma) && (addr < (section->vma + section->size)))
+        break;
+    }
+
+  if (section == NULL)
+    {
+      return;
+    }
+  else if (!(section->flags & SEC_HAS_CONTENTS))
+    {
+      return;
+    }
+
+  dataoff = addr - section->vma;
+
+  /* Read the whole section. */
+  if (!bfd_malloc_and_get_section (abfd, section, &data))
+    {
+      if (data != NULL)
+	free (data);
+      return;
+    }
+
+  /* Search for a CodeView entry in the DebugDirectory */
+  for (i = 0; i < size / sizeof (struct external_IMAGE_DEBUG_DIRECTORY); i++)
+    {
+      struct external_IMAGE_DEBUG_DIRECTORY *ext
+	= &((struct external_IMAGE_DEBUG_DIRECTORY *)(data + dataoff))[i];
+      struct internal_IMAGE_DEBUG_DIRECTORY idd;
+
+      _bfd_XXi_swap_debugdir_in (abfd, ext, &idd);
+
+      if (idd.Type == PE_IMAGE_DEBUG_TYPE_CODEVIEW)
+        {
+          char buffer[256 + 1];
+          CODEVIEW_INFO *cvinfo = (CODEVIEW_INFO *) buffer;
+
+          /*
+            The debug entry doesn't have to have to be in a section, in which
+            case AddressOfRawData is 0, so always use PointerToRawData.
+          */
+          if (_bfd_XXi_slurp_codeview_record (abfd,
+                                              (file_ptr) idd.PointerToRawData,
+                                              idd.SizeOfData, cvinfo))
+            {
+              struct bfd_build_id* build_id = bfd_alloc(abfd,
+                         sizeof(struct bfd_build_id) + cvinfo->SignatureLength);
+              if (build_id)
+                {
+                  build_id->size = cvinfo->SignatureLength;
+                  memcpy(build_id->data,  cvinfo->Signature,
+                         cvinfo->SignatureLength);
+                  abfd->build_id = build_id;
+                }
+            }
+          break;
+        }
+    }
+}
+
 static const bfd_target *
 pe_bfd_object_p (bfd * abfd)
 {
@@ -1265,6 +1346,7 @@ pe_bfd_object_p (bfd * abfd)
   struct internal_aouthdr internal_a;
   file_ptr opt_hdr_size;
   file_ptr offset;
+  const bfd_target *result;
 
   /* Detect if this a Microsoft Import Library Format element.  */
   /* First read the beginning of the header.  */
@@ -1358,10 +1440,20 @@ pe_bfd_object_p (bfd * abfd)
 	return NULL;
     }
 
-  return coff_real_object_p (abfd, internal_f.f_nscns, &internal_f,
-                            (opt_hdr_size != 0
-                             ? &internal_a
-                             : (struct internal_aouthdr *) NULL));
+
+  result = coff_real_object_p (abfd, internal_f.f_nscns, &internal_f,
+                               (opt_hdr_size != 0
+                                ? &internal_a
+                                : (struct internal_aouthdr *) NULL));
+
+
+  if (result)
+    {
+      /* Now the whole header has been processed, see if there is a build-id */
+      pe_bfd_read_buildid(abfd);
+    }
+
+  return result;
 }
 
 #define coff_object_p pe_bfd_object_p