gdb: Fix failure in gdb.base/complex-parts.exp for x86-32

The x86-32 ABI specifies 96-bit long double, this was causing a
failure on the test gdb.base/complex-parts.exp.

The problem is that GDB tries to find a builtin floating point type of
the correct size in order to reuse the name of that type as the name
for the components of the complex type being built.

Previously GDB was only aware of floating point types sized 32, 64, or
128 bits.  This patch teaches GDB how to handle 96 bit floating point
type.

gdb/ChangeLog:

	* dwarf2read.c (dwarf2_init_complex_target_type): Handle complex
	target types of size 96-bits, add some additional comments, and
	check that the builtin type we found was the correct size.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ed054a951f7a35322e96fa98ea178d94e780b595..adafc198d8a87cfe47be452894c0ac4812f67efd 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-13  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+       * dwarf2read.c (dwarf2_init_complex_target_type): Handle complex
+       target types of size 96-bits, add some additional comments, and
+       check that the builtin type we found was the correct size.
+
 2019-04-12  Eli Zaretskii  <eliz@gnu.org>
 
        * utils.c (prompt_for_continue): Don't restore the styling at the

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index b718192cb12ea451f6892d7840f66722ccdb0a95..0873028e438a9028d48184ab3dc73c84b609230e 100644 (file)
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -17546,6 +17546,9 @@ dwarf2_init_complex_target_type (struct dwarf2_cu *cu,
   gdbarch *gdbarch = get_objfile_arch (objfile);
   struct type *tt = nullptr;
 
+  /* Try to find a suitable floating point builtin type of size BITS.
+     We're going to use the name of this type as the name for the complex
+     target type that we are about to create.  */
   switch (bits)
     {
     case 32:
@@ -17554,11 +17557,18 @@ dwarf2_init_complex_target_type (struct dwarf2_cu *cu,
     case 64:
       tt = builtin_type (gdbarch)->builtin_double;
       break;
+    case 96:   /* The x86-32 ABI specifies 96-bit long double.  */
     case 128:
       tt = builtin_type (gdbarch)->builtin_long_double;
       break;
     }
 
+  /* If the type we found doesn't match the size we were looking for, then
+     pretend we didn't find a type at all, the complex target type we
+     create will then be nameless.  */
+  if (TYPE_LENGTH (tt) * TARGET_CHAR_BIT != bits)
+    tt = nullptr;
+
   const char *name = (tt == nullptr) ? nullptr : TYPE_NAME (tt);
   return dwarf2_init_float_type (objfile, bits, name, name_hint);
 }