[PATCH 2/5] gdb/dwarf: move DWP htab nullptr check to lookup_dwo_unit_in_dwp

[simon.marchi@polymtl.ca]

From: Simon Marchi <simon.marchi@polymtl.ca>

cutu_reader::lookup_dwo_cutu gets hold of the right htab for the kind of
unit to look up (CU or TU), but then just uses the pointer to know if it
should call lookup_dwo_unit_in_dwp or not.  lookup_dwo_unit_in_dwp then
uses the same condition to obtain the correct htab.  I think it would
make more sense to return early from lookup_dwo_unit_in_dwp instead, if
the required htab does not exist.

Change-Id: I6f8f96aba2452f8261b3c60667e72fb21b97c89d
---
 gdb/dwarf2/read.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 331f1b9c5261..1b728764f711 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -6967,8 +6967,12 @@ lookup_dwo_unit_in_dwp (dwarf2_per_bfd *per_bfd,
 			struct dwp_file *dwp_file, const char *comp_dir,
 			ULONGEST signature, int is_debug_types)
 {
-  const struct dwp_hash_table *dwp_htab =
-    is_debug_types ? dwp_file->tus : dwp_file->cus;
+  const dwp_hash_table *dwp_htab
+    = is_debug_types ? dwp_file->tus : dwp_file->cus;
+
+  if (dwp_htab == nullptr)
+    return nullptr;
+
   bfd *dbfd = dwp_file->dbfd.get ();
   uint32_t mask = dwp_htab->nr_slots - 1;
   uint32_t hash = signature & mask;
@@ -7522,25 +7526,19 @@ cutu_reader::lookup_dwo_cutu (dwarf2_cu *cu, const char *dwo_name,
 
   dwp_file *dwp_file = per_objfile->per_bfd->dwp_file.get ();
 
-  if (dwp_file != NULL)
+  if (dwp_file != nullptr)
     {
-      const struct dwp_hash_table *dwp_htab =
-	is_debug_types ? dwp_file->tus : dwp_file->cus;
+      dwo_unit *dwo_cutu
+	= lookup_dwo_unit_in_dwp (per_bfd, dwp_file, comp_dir, signature,
+				  is_debug_types);
 
-      if (dwp_htab != NULL)
+      if (dwo_cutu != nullptr)
 	{
-	  struct dwo_unit *dwo_cutu =
-	    lookup_dwo_unit_in_dwp (per_bfd, dwp_file, comp_dir, signature,
-				    is_debug_types);
+	  dwarf_read_debug_printf ("Virtual DWO %s %s found: @%s",
+				   kind, hex_string (signature),
+				   host_address_to_string (dwo_cutu));
 
-	  if (dwo_cutu != NULL)
-	    {
-	      dwarf_read_debug_printf ("Virtual DWO %s %s found: @%s",
-				       kind, hex_string (signature),
-				       host_address_to_string (dwo_cutu));
-
-	      return dwo_cutu;
-	    }
+	  return dwo_cutu;
 	}
     }
   else
-- 
2.52.0