gdb: Fix alignment computation for structs with only static fields

The current code in gdbtypes.c:type_align incorrectly returns 0 as the
alignment for a structure containing only static fields.  After this
patch the correct value of 1 is returned.  The gdb.base/align.exp test
is extended to cover this case.

gdb/ChangeLog:

	* gdbtypes.c (type_align): A struct with no non-static fields also
	has alignment of 1.

gdb/testsuite/ChangeLog:

	* gdb.base/align.exp: Extend test to cover structures containing
	only static fields.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 0be7538..d50a034 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2019-04-11  Andrew Burgess  <andrew.burgess@embecosm.com>
 
+       * gdbtypes.c (type_align): A struct with no non-static fields also
+       has alignment of 1.
+
+2019-04-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
        * riscv-tdep.c (riscv_call_arg_complex_float): Fix offset of first
        component to 0.
        (riscv_struct_info::riscv_struct_info): Initialise m_offsets

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 919feac..683238d 100644 (file)
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -3014,16 +3014,12 @@ type_align (struct type *type)
     case TYPE_CODE_STRUCT:
     case TYPE_CODE_UNION:
       {
-       if (TYPE_NFIELDS (type) == 0)
-         {
-           /* An empty struct has alignment 1.  */
-           align = 1;
-           break;
-         }
+       int number_of_non_static_fields = 0;
        for (unsigned i = 0; i < TYPE_NFIELDS (type); ++i)
          {
            if (!field_is_static (&TYPE_FIELD (type, i)))
              {
+               number_of_non_static_fields++;
                ULONGEST f_align = type_align (TYPE_FIELD_TYPE (type, i));
                if (f_align == 0)
                  {
@@ -3035,6 +3031,10 @@ type_align (struct type *type)
                  align = f_align;
              }
          }
+       /* A struct with no fields, or with only static fields has an
+          alignment of 1.  */
+       if (number_of_non_static_fields == 0)
+         align = 1;
       }
       break;
 

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index dfbee85..3b952b8 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-04-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+       * gdb.base/align.exp: Extend test to cover structures containing
+       only static fields.
+
 2019-04-11  Tom de Vries  <tdevries@suse.de>
 
        * boards/cc-with-dwz-m.exp: New file.

diff --git a/gdb/testsuite/gdb.base/align.exp b/gdb/testsuite/gdb.base/align.exp
index 558625d..e3ca047 100644 (file)
--- a/gdb/testsuite/gdb.base/align.exp
+++ b/gdb/testsuite/gdb.base/align.exp
@@ -67,8 +67,10 @@ proc prepare_test_source_file { lang } {
     puts -nonewline $outfile "#define DEF(T,U) struct align_pair_ ## T ## _x_ ## U "
     puts $outfile "{ T one; U two; }"
     if { $lang == "c++" } {
-       puts -nonewline $outfile "#define DEF_WITH_STATIC(T,U) struct align_pair_static_ ## T ## _x_ ## U "
+       puts -nonewline $outfile "#define DEF_WITH_1_STATIC(T,U) struct align_pair_static_ ## T ## _x_ ## U "
        puts $outfile "{ static T one; U two; }"
+       puts -nonewline $outfile "#define DEF_WITH_2_STATIC(T,U) struct align_pair_static_ ## T ## _x_static_ ## U "
+       puts $outfile "{ static T one; static U two; }"
     }
     if { $lang == "c" } {
        puts $outfile "unsigned a_void = ${align_func} (void);"
@@ -99,11 +101,17 @@ proc prepare_test_source_file { lang } {
            puts $outfile "  = ${align_func} (struct align_pair_${joined});"
 
            if { $lang == "c++" } {
-               puts $outfile "DEF_WITH_STATIC ($utype, $uinner);"
-               set joined "${utype}_x_${uinner}"
-               puts $outfile "struct align_pair_static_$joined item_static_${joined};"
-               puts $outfile "unsigned a_static_${joined}"
-               puts $outfile "  = ${align_func} (struct align_pair_static_${joined});"
+               puts $outfile "DEF_WITH_1_STATIC ($utype, $uinner);"
+               set joined "static_${utype}_x_${uinner}"
+               puts $outfile "struct align_pair_$joined item_${joined};"
+               puts $outfile "unsigned a_${joined}"
+               puts $outfile "  = ${align_func} (struct align_pair_${joined});"
+
+               puts $outfile "DEF_WITH_2_STATIC ($utype, $uinner);"
+               set joined "static_${utype}_x_static_${uinner}"
+               puts $outfile "struct align_pair_$joined item_${joined};"
+               puts $outfile "unsigned a_${joined}"
+               puts $outfile "  = ${align_func} (struct align_pair_${joined});"
            }
        }
     }
@@ -160,6 +168,10 @@ proc run_alignment_test { lang } {
                set expected [get_integer_valueof a_static_${utype}_x_${uinner} 0]
                gdb_test "print ${align_func}(struct align_pair_static_${utype}_x_${uinner})" \
                    " = $expected"
+
+               set expected [get_integer_valueof a_static_${utype}_x_static_${uinner} 0]
+               gdb_test "print ${align_func}(struct align_pair_static_${utype}_x_static_${uinner})" \
+                   " = $expected"
            }
        }
     }