Support DW_FORM_strx1, _strx2, _strx3, _strx4 forms.

Dwarf5 defines DW_FORM_strx1 and others, which are similar
to DW_FORM_strx but uses 1-4 bytes unsigned integers. This is
a small step towards supporting dwarf5 in gdb.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 126343c..fdbcb67 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-04-30  Ali Tamur  <tamur@google.com>
+       * gdb/dwarf2read.c (read_3_bytes): New declaration.
+       (read_attribute_value): Added DW_FORM_strx1-4 cases.
+       (read_3_bytes): New function.
+
 2019-04-30  Joel Brobecker  <brobecker@adacore.com>
 
        * windows-nat.c (main_thread_id): Delete.

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 751c59c..b0bdecf 100644 (file)
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1531,6 +1531,9 @@ static int read_1_signed_byte (bfd *, const gdb_byte *);
 
 static unsigned int read_2_bytes (bfd *, const gdb_byte *);
 
+/* Read the next three bytes (little-endian order) as an unsigned integer.  */
+static unsigned int read_3_bytes (bfd *, const gdb_byte *);
+
 static unsigned int read_4_bytes (bfd *, const gdb_byte *);
 
 static ULONGEST read_8_bytes (bfd *, const gdb_byte *);
@@ -19330,6 +19333,10 @@ read_attribute_value (const struct die_reader_specs *reader,
       info_ptr += bytes_read;
       break;
     case DW_FORM_strx:
+    case DW_FORM_strx1:
+    case DW_FORM_strx2:
+    case DW_FORM_strx3:
+    case DW_FORM_strx4:
     case DW_FORM_GNU_str_index:
       if (reader->dwo_file == NULL)
        {
@@ -19340,12 +19347,34 @@ read_attribute_value (const struct die_reader_specs *reader,
                 bfd_get_filename (abfd));
        }
       {
-       ULONGEST str_index =
-         read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
-
+       ULONGEST str_index;
+       if (form == DW_FORM_strx1)
+         {
+           str_index = read_1_byte (abfd, info_ptr);
+           info_ptr += 1;
+         }
+       else if (form == DW_FORM_strx2)
+         {
+           str_index = read_2_bytes (abfd, info_ptr);
+           info_ptr += 2;
+         }
+       else if (form == DW_FORM_strx3)
+         {
+           str_index = read_3_bytes (abfd, info_ptr);
+           info_ptr += 3;
+         }
+       else if (form == DW_FORM_strx4)
+         {
+           str_index = read_4_bytes (abfd, info_ptr);
+           info_ptr += 4;
+         }
+       else
+         {
+           str_index = read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
+           info_ptr += bytes_read;
+         }
        DW_STRING (attr) = read_str_index (reader, str_index);
        DW_STRING_IS_CANONICAL (attr) = 0;
-       info_ptr += bytes_read;
       }
       break;
     default:
@@ -19416,6 +19445,19 @@ read_2_signed_bytes (bfd *abfd, const gdb_byte *buf)
 }
 
 static unsigned int
+read_3_bytes (bfd *abfd, const gdb_byte *buf)
+{
+  unsigned int result = 0;
+  for (int i = 0; i < 3; ++i)
+    {
+      unsigned char byte = bfd_get_8 (abfd, buf);
+      buf++;
+      result |= ((unsigned int) byte << (i * 8));
+    }
+  return result;
+}
+
+static unsigned int
 read_4_bytes (bfd *abfd, const gdb_byte *buf)
 {
   return bfd_get_32 (abfd, buf);

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 8d2601b..fa1f567 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-04-30  Ali Tamur  <tamur@google.com>
+
+       * lib/dwarf.exp(): Added DW_FORM_strx1-4.
+
 2019-04-30  Tom Tromey  <tromey@adacore.com>
 
        * lib/ada.exp (find_ada_tool): New proc.

diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp
index 3a430fc..3cc5928 100644 (file)
--- a/gdb/testsuite/lib/dwarf.exp
+++ b/gdb/testsuite/lib/dwarf.exp
@@ -528,6 +528,10 @@ namespace eval Dwarf {
            DW_FORM_exprloc -
 
            DW_FORM_strx -
+           DW_FORM_strx1 -
+           DW_FORM_strx2 -
+           DW_FORM_strx3 -
+           DW_FORM_strx4 -
 
            DW_FORM_GNU_addr_index -
            DW_FORM_GNU_str_index -