> That depends a bit on the compiler version and optimization level,
> but (in particular in the 3.x time frame) GCC may output assembler
> code on a function-by-function basis, without necessarily reading
> in the whole source file first.
Ok, actually it doesn't matter if it doesn't work all the time. I'll
always be compiling with -Os anyway, so it sounds like I'm in
with a chance of the whole file being read first?
If so, where is my first opportunity, in 3.2.3, to see if there's a
"main" function in this file?
Hmm, it seems 3.2.x would *always* operate on a function-by-function
basis. The unit-at-a-time mode was only introduced with 3.4 (I don't
recall if it was already present in 3.3). I don't think there is any
way in 3.2.3 to check whether there is a "main" function in the file
before it is processed ...
Does that mean I could take advantage of this behaviour? Currently
I have this change:
/* Store in OUTPUT a string (made with alloca) containing an
assembler-name for a local static variable named NAME.
LABELNO is an integer which is different for each call. */
#ifdef TARGET_PDPMAC
#define ASM_FORMAT_PRIVATE_NAME(OUTPUT, NAME, LABELNO) ^I^I\
{^I^I^I^I^I^I^I^I^I\
(OUTPUT) = (char *) alloca (strlen ((NAME)) + 10);^I^I^I\
sprintf ((OUTPUT), "__%d", (LABELNO));^I^I^I^I\
}
to give the static functions unique names within the file.
However, it has the unfortunate side-effect that this code:
#if defined(TARGET_DIGNUS) || defined(TARGET_PDPMAC)
#define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)^I^I^I\
{^I^I^I^I^I^I^I^I^I\
if (strlen (NAME) + 1 > mvs_function_name_length)^I^I^I\
{^I^I^I^I^I^I^I^I^I\
if (mvs_function_name)^I^I^I^I^I^I\
^Ifree (mvs_function_name);^I^I^I^I^I\
mvs_function_name = 0;^I^I^I^I^I^I\
}^I^I^I^I^I^I^I^I^I\
if (!mvs_function_name)^I^I^I^I^I^I\
{^I^I^I^I^I^I^I^I^I\
mvs_function_name_length = strlen (NAME) * 2 + 1;^I^I^I\
mvs_function_name = (char *) xmalloc (mvs_function_name_length);^I\
}^I^I^I^I^I^I^I^I^I\
strcpy (mvs_function_name, NAME);^I^I^I^I^I\
mvs_need_to_globalize = 1;^I^I^I^I^I^I\
}
#endif
static void
i370_output_function_prologue (f, l)
FILE *f;
HOST_WIDE_INT l;
{
/* Don't print stack and args in PDPMAC as it makes the
comment too long */
#ifdef TARGET_PDPMAC
fprintf (f, "* %c-func %s prologue\n",
mvs_need_entry ? 'X' : 'S',
mvs_function_name);
#else
is producing this output:
* S-func __0 prologue
@@0 PDPPRLG CINDEX=1,FRAME=88,BASER=12,ENTRY=NO
B FEN1
LTORG
FEN1 EQU *
DROP 12
BALR 12,0
USING *,12
PG1 EQU *
LR 11,1
L 10,=A(PGT1)
* Function __0 code
* 46 world.c
SLR 15,15
* Function __0 epilogue
PDPEPIL
* Function __0 literal pool
DS 0F
LTORG
* Function __0 page table
DS 0F
PGT1 EQU *
DC A(PG1)
for this function:
static int aaa(void)
{
return (0);
}
ie the "aaa" is being completely lost, being replaced by __0 everywhere.
Ideally the __0 would be aaa everywhere, with just the @@0 remaining
generated.
Indeed, I have just made this change:
C:\devel\gcc\gcc>cd config\i370
C:\devel\gcc\gcc\config\i370>cvs diff
cvs diff: Diffing .
Index: i370.c
===================================================================
RCS file: c:\cvsroot/gcc/gcc/config/i370/i370.c,v
retrieving revision 1.34
diff -r1.34 i370.c
84a85,87
/* original name of a static variable */
char origmvsstatic[150];
1457c1460
< mvs_function_name);
---
mvs_need_entry ? mvs_function_name : origmvsstatic);
1599c1602,1603
< fprintf (f, "* Function %s code\n", mvs_function_name);
---
fprintf (f, "* Function %s code\n",
mvs_need_entry ? mvs_function_name : origmvsstatic);
1787c1791,1792
< fprintf (file, "* Function %s epilogue\n", mvs_function_name);
---
fprintf (file, "* Function %s epilogue\n",
mvs_need_entry ? mvs_function_name : origmvsstatic);
1818c1823,1824
< fprintf (file, "* Function %s literal pool\n", mvs_function_name);
---
fprintf (file, "* Function %s literal pool\n",
mvs_need_entry ? mvs_function_name : origmvsstatic);
1821c1827,1828
< fprintf (file, "* Function %s page table\n", mvs_function_name);
---
fprintf (file, "* Function %s page table\n",
mvs_need_entry ? mvs_function_name : origmvsstatic);
C:\devel\gcc\gcc\config\i370>cvs diff -c i370.h
Index: i370.h
===================================================================
RCS file: c:\cvsroot/gcc/gcc/config/i370/i370.h,v
retrieving revision 1.35
diff -c -r1.35 i370.h
*** i370.h 18 Jul 2009 08:56:33 -0000 1.35
--- i370.h 20 Aug 2009 10:40:35 -0000
***************
*** 57,62 ****
--- 57,63 ----
/* The source file module. */
extern char *mvs_module;
+ extern char origmvsstatic[];
/* Compile using char instructions (mvc, nc, oc, xc). On 4341 use this
since
these are more than twice as fast as load-op-store.
***************
*** 1832,1837 ****
--- 1833,1839 ----
#define ASM_FORMAT_PRIVATE_NAME(OUTPUT, NAME, LABELNO) \
{ \
(OUTPUT) = (char *) alloca (strlen ((NAME)) + 10); \
+ strcpy(origmvsstatic, NAME); \
sprintf ((OUTPUT), "__%d", (LABELNO)); \
}
#else
and it is working:
* S-func aaa prologue
@@0 PDPPRLG CINDEX=1,FRAME=88,BASER=12,ENTRY=NO
B FEN1
LTORG
FEN1 EQU *
DROP 12
BALR 12,0
USING *,12
PG1 EQU *
LR 11,1
L 10,=A(PGT1)
* Function aaa code
* 46 world.c
SLR 15,15
* Function aaa epilogue
PDPEPIL
* Function aaa literal pool
DS 0F
LTORG
* Function aaa page table
DS 0F
PGT1 EQU *
DC A(PG1)
But is that guaranteed?
Thanks. Paul.
