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The powerpc64 ABIs align structs passed by value, a fact ignored by

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gcc for quite some time.  Since gcc now does the correct alignment,
libffi needs to follow suit.  This ought to be made selectable via
a new abi value, and the #ifdefs removed from ffi.c along with many
other #ifdefs present there and in assembly.  I'll do that with a
followup patch sometime.

This is a revised version of
https://sourceware.org/ml/libffi-discuss/2013/msg00162.html
This commit is contained in:
Alan Modra
2013-11-16 06:41:36 -05:00
committed by Anthony Green
parent a97cf1fae5
commit 1c06515d92
2 changed files with 40 additions and 0 deletions
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7
ChangeLog
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@@ -1,3 +1,10 @@
2013-11-16 Alan Modra <amodra@gmail.com>
* src/powerpc/ffi.c (ffi_prep_args64): Align struct parameters
according to __STRUCT_PARM_ALIGN__.
(ffi_prep_cif_machdep_core): Likewise.
(ffi_closure_helper_LINUX64): Likewise.
2013-11-16 Alan Modra <amodra@gmail.com>
* src/powerpc/linux64.S (ffi_call_LINUX64): Tweak restore of r28.

33
src/powerpc/ffi.c
View File

@@ -439,6 +439,7 @@ ffi_prep_args64 (extended_cif *ecif, unsigned long *const stack)
unsigned long *ul;
float *f;
double *d;
size_t p;
} valp;
/* 'stacktop' points at the previous backchain pointer. */
@@ -473,6 +474,9 @@ ffi_prep_args64 (extended_cif *ecif, unsigned long *const stack)
double **d;
} p_argv;
unsigned long gprvalue;
#ifdef __STRUCT_PARM_ALIGN__
unsigned long align;
#endif
stacktop.c = (char *) stack + bytes;
gpr_base.ul = stacktop.ul - ASM_NEEDS_REGISTERS64 - NUM_GPR_ARG_REGISTERS64;
@@ -549,6 +553,13 @@ ffi_prep_args64 (extended_cif *ecif, unsigned long *const stack)
#endif
case FFI_TYPE_STRUCT:
#ifdef __STRUCT_PARM_ALIGN__
align = (*ptr)->alignment;
if (align > __STRUCT_PARM_ALIGN__)
align = __STRUCT_PARM_ALIGN__;
if (align > 1)
next_arg.p = ALIGN (next_arg.p, align);
#endif
words = ((*ptr)->size + 7) / 8;
if (next_arg.ul >= gpr_base.ul && next_arg.ul + words > gpr_end.ul)
{
@@ -853,6 +864,10 @@ ffi_prep_cif_machdep_core (ffi_cif *cif)
else
for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
{
#ifdef __STRUCT_PARM_ALIGN__
unsigned int align;
#endif
switch ((*ptr)->type)
{
#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
@@ -868,6 +883,14 @@ ffi_prep_cif_machdep_core (ffi_cif *cif)
break;
case FFI_TYPE_STRUCT:
#ifdef __STRUCT_PARM_ALIGN__
align = (*ptr)->alignment;
if (align > __STRUCT_PARM_ALIGN__)
align = __STRUCT_PARM_ALIGN__;
align = align / 8;
if (align > 1)
intarg_count = ALIGN (intarg_count, align);
#endif
intarg_count += ((*ptr)->size + 7) / 8;
break;
@@ -1399,6 +1422,9 @@ ffi_closure_helper_LINUX64 (ffi_closure *closure, void *rvalue,
unsigned long i, avn, nfixedargs;
ffi_cif *cif;
ffi_dblfl *end_pfr = pfr + NUM_FPR_ARG_REGISTERS64;
#ifdef __STRUCT_PARM_ALIGN__
unsigned long align;
#endif
cif = closure->cif;
avalue = alloca (cif->nargs * sizeof (void *));
@@ -1453,6 +1479,13 @@ ffi_closure_helper_LINUX64 (ffi_closure *closure, void *rvalue,
break;
case FFI_TYPE_STRUCT:
#ifdef __STRUCT_PARM_ALIGN__
align = arg_types[i]->alignment;
if (align > __STRUCT_PARM_ALIGN__)
align = __STRUCT_PARM_ALIGN__;
if (align > 1)
pst = (unsigned long *) ALIGN ((size_t) pst, align);
#endif
#ifndef __LITTLE_ENDIAN__
/* Structures with size less than eight bytes are passed
left-padded. */