Re: Target dependent frag fields (proposed change)

Re: Target dependent frag fields (proposed change)

[Doug Evans]

Ian.Dall@dsto.defence.gov.au (Ian Dall) writes:
> Following the comments in as.h, I decided to have a look at making the
> fields needed for the ns32k configurable.
> 
> This turned out to not be very hard. Basically the problem is that you
> would want targ-*.h to define TC_FRAG_TYPE (like TC_FIX_TYPE for the
> fix structure), but the targ-*.h use the frag structure quite a bit so
> it has to be defined before the targ-*.h.

I checked in something along these lines and will be in the
next snapshot.

Target dependent frag fields (proposed change)

[Ian Dall]

Following the comments in as.h, I decided to have a look at making the
fields needed for the ns32k configurable.

This turned out to not be very hard. Basically the problem is that you
would want targ-*.h to define TC_FRAG_TYPE (like TC_FIX_TYPE for the
fix structure), but the targ-*.h use the frag structure quite a bit so
it has to be defined before the targ-*.h.

The solution to to have an incomplete definition

  struct frag;

before including the targ-*.h and defer a complete definition until
afterwards.

I don't have the resources to test this for all targets, but it works
for the ns32k and looks safe for other targets.

Ian


ChangeLog Entry:


Wed Nov  5 00:00:20 1997  Ian Dall  <Ian.Dall@dsto.defence.gov.au>

	* as.h: Move struct frag definition to after targ-*.h is
 	included. Leave incomplete definition at old place. (struct frag):
 	Add TC_FRAG_TYPE analagously to TC_FIX_TYPE.

	* config/tc-ns32k.h (TC_FRAG_TYPE): Define to contain ns32k target
 	dependent frag fields. (frag_opcode_frag, frag_opcode_offset,
 	frag_bsr): change to reflect TC_FRAG_TYPE definition.

Patch:

diff -rc ../gas-build/gas/as.h ./gas/as.h
*** ../gas-build/gas/as.h	Wed Oct 29 22:57:20 1997
--- ./gas/as.h	Tue Nov  4 22:45:52 1997
***************
*** 395,472 ****
  typedef addressT relax_addressT;
  \f
  
! /* frags.c */
! 
! /*
!  * A code fragment (frag) is some known number of chars, followed by some
!  * unknown number of chars. Typically the unknown number of chars is an
!  * instruction address whose size is yet unknown. We always know the greatest
!  * possible size the unknown number of chars may become, and reserve that
!  * much room at the end of the frag.
!  * Once created, frags do not change address during assembly.
!  * We chain the frags in (a) forward-linked list(s). The object-file address
!  * of the 1st char of a frag is generally not known until after relax().
!  * Many things at assembly time describe an address by {object-file-address
!  * of a particular frag}+offset.
! 
!  BUG: it may be smarter to have a single pointer off to various different
!  notes for different frag kinds. See how code pans
!  */
! 
  typedef struct frag fragS;
  
- struct frag
- {
-   /* Object file address. */
-   addressT fr_address;
-   /* Chain forward; ascending address order.  Rooted in frch_root. */
-   struct frag *fr_next;
- 
-   /* (Fixed) number of chars we know we have.  May be 0. */
-   offsetT fr_fix;
-   /* (Variable) number of chars after above.  May be 0. */
-   offsetT fr_var;
-   /* For variable-length tail. */
-   struct symbol *fr_symbol;
-   /* For variable-length tail. */
-   offsetT fr_offset;
-   /* Points to opcode low addr byte, for relaxation.  */
-   char *fr_opcode;
- 
- #ifndef NO_LISTING
-   struct list_info_struct *line;
- #endif
- 
-   /* What state is my tail in? */
-   relax_stateT fr_type;
-   relax_substateT fr_subtype;
- 
-   union {
-     /* These are needed only on the NS32K machines.  But since we don't
-        include targ-cpu.h until after this structure has been defined,
-        we can't really conditionalize it.  This code should be
-        rearranged a bit to make that possible.  */
-     struct {
-       fragS *fr_opcode_fragP;
-       unsigned int fr_opcode_offset;
-       char fr_bsr;
-     } fr_ns32k;
- #ifdef USING_CGEN
-     /* Don't include this unless using CGEN to keep frag size down.  */
-     struct {
-       const struct cgen_insn *insn;
-       unsigned char opindex, opinfo;
-     } cgen;
- #endif
-   } fr_targ;
- 
-   /* Where the frag was created, or where it became a variant frag.  */
-   char *fr_file;
-   unsigned int fr_line;
- 
-   /* Data begins here.  */
-   char fr_literal[1];
- };
  
  #define SIZEOF_STRUCT_FRAG \
  ((char *)zero_address_frag.fr_literal-(char *)&zero_address_frag)
--- 395,404 ----
  typedef addressT relax_addressT;
  \f
  
! struct frag;			/* Complete definition after target
! 				   dependent includes */
  typedef struct frag fragS;
  
  
  #define SIZEOF_STRUCT_FRAG \
  ((char *)zero_address_frag.fr_literal-(char *)&zero_address_frag)
***************
*** 656,661 ****
--- 588,660 ----
  
  /* this one starts the chain of target dependant headers */
  #include "targ-env.h"
+ 
+ /* frags.c */
+ 
+ /*
+  * A code fragment (frag) is some known number of chars, followed by some
+  * unknown number of chars. Typically the unknown number of chars is an
+  * instruction address whose size is yet unknown. We always know the greatest
+  * possible size the unknown number of chars may become, and reserve that
+  * much room at the end of the frag.
+  * Once created, frags do not change address during assembly.
+  * We chain the frags in (a) forward-linked list(s). The object-file address
+  * of the 1st char of a frag is generally not known until after relax().
+  * Many things at assembly time describe an address by {object-file-address
+  * of a particular frag}+offset.
+ 
+  BUG: it may be smarter to have a single pointer off to various different
+  notes for different frag kinds. See how code pans
+  */
+ 
+ struct frag
+ {
+   /* Object file address. */
+   addressT fr_address;
+   /* Chain forward; ascending address order.  Rooted in frch_root. */
+   struct frag *fr_next;
+ 
+   /* (Fixed) number of chars we know we have.  May be 0. */
+   offsetT fr_fix;
+   /* (Variable) number of chars after above.  May be 0. */
+   offsetT fr_var;
+   /* For variable-length tail. */
+   struct symbol *fr_symbol;
+   /* For variable-length tail. */
+   offsetT fr_offset;
+   /* Points to opcode low addr byte, for relaxation.  */
+   char *fr_opcode;
+ 
+ #ifndef NO_LISTING
+   struct list_info_struct *line;
+ #endif
+ 
+   /* What state is my tail in? */
+   relax_stateT fr_type;
+   relax_substateT fr_subtype;
+ 
+ #ifdef TC_FRAG_TYPE
+   TC_FRAG_TYPE tc_frag_data;
+ #endif
+ 
+ #ifdef USING_CGEN
+   /* Don't include this unless using CGEN to keep frag size down.
+      Change tc file to use TC_FRAG_TYPE */
+   union {
+     struct {
+       const struct cgen_insn *insn;
+       unsigned char opindex, opinfo;
+     } cgen;
+   } fr_targ;
+ #endif
+ 
+   /* Where the frag was created, or where it became a variant frag.  */
+   char *fr_file;
+   unsigned int fr_line;
+ 
+   /* Data begins here.  */
+   char fr_literal[1];
+ };
  
  #include "struc-symbol.h"
  #include "write.h"
diff -rc ../gas-build/gas/config/tc-ns32k.h ./gas/config/tc-ns32k.h
*** ../gas-build/gas/config/tc-ns32k.h	Wed Oct 29 22:57:23 1997
--- ./gas/config/tc-ns32k.h	Mon Nov  3 23:30:53 1997
***************
*** 102,128 ****
  
  
  #define TC_FIX_DATA_PRINT(FILE, TC_FIX)					\
!   do									\
!     {									\
!       fprintf((FILE), "\nopcode_frag=%p operand offset=%d,		\
!               bsr=%d" , (TC_FIX).opcode_fragP, (TC_FIX).opcode_offset,	\
!               (TC_FIX).bsr);						\
!     }									\
!   while(0)
  
  #define TC_FRAG_INIT(X)				\
!   do						\
!      {						\
!        frag_opcode_frag(X) = NULL;		\
!        frag_opcode_offset(X) = 0;		\
!        frag_bsr(X) = 0;				\
!      }						\
!   while(0)
  
  /* Accessor macros for things which may move around */
! #define frag_opcode_frag(X) (X)->fr_targ.fr_ns32k.fr_opcode_fragP
! #define frag_opcode_offset(X) (X)->fr_targ.fr_ns32k.fr_opcode_offset
! #define frag_bsr(X) (X)->fr_targ.fr_ns32k.fr_bsr
  
  #define TC_FIX_TYPE				\
  struct						\
--- 102,135 ----
  
  
  #define TC_FIX_DATA_PRINT(FILE, TC_FIX)					\
! do									\
! {									\
!   fprintf((FILE), "\nopcode_frag=%p operand offset=%d, bsr=%d",		\
! 	  (TC_FIX).opcode_fragP, (TC_FIX).opcode_offset, (TC_FIX).bsr);	\
! }									\
! while(0)
  
  #define TC_FRAG_INIT(X)				\
! do						\
! {						\
!   frag_opcode_frag(X) = NULL;			\
!   frag_opcode_offset(X) = 0;			\
!   frag_bsr(X) = 0;				\
! }						\
! while(0)
! 
! #define TC_FRAG_TYPE				\
! struct {					\
!   fragS *fr_opcode_fragP;			\
!   unsigned int fr_opcode_offset;		\
!   char fr_bsr;					\
! }
! 
  
  /* Accessor macros for things which may move around */
! #define frag_opcode_frag(X) (X)->tc_frag_data.fr_opcode_fragP
! #define frag_opcode_offset(X) (X)->tc_frag_data.fr_opcode_offset
! #define frag_bsr(X) (X)->tc_frag_data.fr_bsr
  
  #define TC_FIX_TYPE				\
  struct						\