[RFA] Support for multiple calling conventions, patch 1/3: Add calling convention to struct type

[Corinna Vinschen <vinschen at redhat dot com>]

Hi,

this is the first of three patches which enable to use calling convention
information in the dwarf2 information in GDB.  The general problem has
been discussed in http://sources.redhat.com/ml/gdb/2008-04/msg00090.html

The first patch (this one) just enables the basic use of the dawrf2
calling convention.

The second patch is a pure mechanical patch which adds the function type
information to calls of gdbarch_return_value.

The third patch enables to use the calling convention information
specifically for the sh target.

Ok, now the first patch.  It just adds the calling_convention member to
struct type and fills it in dwarf2read.c:read_subroutine_type so that
all function types have a calling convention information if the debug
information is given as dwarf2.

The result looks like this:

  ftype->calling_convention == 0
  
    if no debug information is available for the function or if the
    debug information is not given as dwarf2.

  ftype->calling_convention == DW_CC_normal
  
    if dwarf2 debug information is available for the function but no
    DW_AT_calling_convention attribute has been given for the function.

  ftype->calling_convention == DW_UNSND(DW_AT_calling_convention)

    if dwarf2 debug information is available for the function and the
    DW_AT_calling_convention attribute has been specified.

If the calling convention can be retrieved by other means, this could
now be added easily.


Ok to apply?

Thanks,
Corinna


        * gdbtypes.h (struct type): Add calling_convention member.
        * dwarf2read.c (read_subroutine_type): Add calling convention read
        from DW_AT_calling_convention attribute to function type.


Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.254
diff -u -p -r1.254 dwarf2read.c
--- dwarf2read.c	26 Mar 2008 14:53:28 -0000	1.254
+++ dwarf2read.c	15 Apr 2008 10:41:36 -0000
@@ -4889,6 +4889,12 @@ read_subroutine_type (struct die_info *d
       || cu->language == language_pascal)
     TYPE_FLAGS (ftype) |= TYPE_FLAG_PROTOTYPED;
 
+  /* Store the calling convention in the type if it's available in
+     the subroutine die.  Otherwise set the calling convention to
+     the default value DW_CC_normal.  */
+  attr = dwarf2_attr (die, DW_AT_calling_convention, cu);
+  ftype->calling_convention = attr ? DW_UNSND (attr) : DW_CC_normal;
+  
   if (die->child != NULL)
     {
       struct die_info *child_die;
Index: gdbtypes.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbtypes.h,v
retrieving revision 1.85
diff -u -p -r1.85 gdbtypes.h
--- gdbtypes.h	3 Feb 2008 22:13:29 -0000	1.85
+++ gdbtypes.h	15 Apr 2008 10:41:37 -0000
@@ -510,6 +510,11 @@ struct type
      on the ring we are.  */
   int instance_flags;
 
+  /* For function types, the calling convention for targets supporting
+     multiple ABIs.  Right now this is only fetched from the Dwarf-2
+     DW_AT_calling_convention attribute.  */
+  unsigned calling_convention;
+
   /* Length of storage for a value of this type.  This is what
      sizeof(type) would return; use it for address arithmetic,
      memory reads and writes, etc.  This size includes padding.  For
@@ -759,6 +764,7 @@ extern void allocate_cplus_struct_type (
   (TYPE_CPLUS_SPECIFIC(type) != &cplus_struct_default)
 
 #define TYPE_INSTANCE_FLAGS(thistype) (thistype)->instance_flags
+#define TYPE_CALLING_CONVENTION(thistype) (thistype)->calling_convention
 #define TYPE_MAIN_TYPE(thistype) (thistype)->main_type
 #define TYPE_NAME(thistype) TYPE_MAIN_TYPE(thistype)->name
 #define TYPE_TAG_NAME(type) TYPE_MAIN_TYPE(type)->tag_name


-- 
Corinna Vinschen
Cygwin Project Co-Leader
Red Hat