Edit
kc3-lang/libffi/src/arm/ffi.c
Russell Keith-Magee
- src/arm/ffi.c
-
/* ----------------------------------------------------------------------- ffi.c - Copyright (c) 2011 Timothy Wall Copyright (c) 2011 Plausible Labs Cooperative, Inc. Copyright (c) 2011 Anthony Green Copyright (c) 2011 Free Software Foundation Copyright (c) 1998, 2008, 2011 Red Hat, Inc. ARM Foreign Function Interface Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ``Software''), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ----------------------------------------------------------------------- */ #include <fficonfig.h> #include <ffi.h> #include <ffi_common.h> #include <stdlib.h> #include "internal.h" #if FFI_EXEC_TRAMPOLINE_TABLE #ifdef __MACH__ #include <mach/vm_param.h> #endif #else extern unsigned int ffi_arm_trampoline[2] FFI_HIDDEN; #endif /* Forward declares. */ static int vfp_type_p (const ffi_type *); static void layout_vfp_args (ffi_cif *); static void * ffi_align (ffi_type *ty, void *p) { /* Align if necessary */ size_t alignment; #ifdef _WIN32_WCE alignment = 4; #else alignment = ty->alignment; if (alignment < 4) alignment = 4; #endif return (void *) ALIGN (p, alignment); } static size_t ffi_put_arg (ffi_type *ty, void *src, void *dst) { size_t z = ty->size; switch (ty->type) { case FFI_TYPE_SINT8: *(UINT32 *)dst = *(SINT8 *)src; break; case FFI_TYPE_UINT8: *(UINT32 *)dst = *(UINT8 *)src; break; case FFI_TYPE_SINT16: *(UINT32 *)dst = *(SINT16 *)src; break; case FFI_TYPE_UINT16: *(UINT32 *)dst = *(UINT16 *)src; break; case FFI_TYPE_INT: case FFI_TYPE_SINT32: case FFI_TYPE_UINT32: case FFI_TYPE_POINTER: case FFI_TYPE_FLOAT: *(UINT32 *)dst = *(UINT32 *)src; break; case FFI_TYPE_SINT64: case FFI_TYPE_UINT64: case FFI_TYPE_DOUBLE: *(UINT64 *)dst = *(UINT64 *)src; break; case FFI_TYPE_STRUCT: case FFI_TYPE_COMPLEX: memcpy (dst, src, z); break; default: abort(); } return ALIGN (z, 4); } /* ffi_prep_args is called once stack space has been allocated for the function's arguments. The vfp_space parameter is the load area for VFP regs, the return value is cif->vfp_used (word bitset of VFP regs used for passing arguments). These are only used for the VFP hard-float ABI. */ static void ffi_prep_args_SYSV (ffi_cif *cif, int flags, void *rvalue, void **avalue, char *argp) { ffi_type **arg_types = cif->arg_types; int i, n; if (flags == ARM_TYPE_STRUCT) { *(void **) argp = rvalue; argp += 4; } for (i = 0, n = cif->nargs; i < n; i++) { ffi_type *ty = arg_types[i]; argp = ffi_align (ty, argp); argp += ffi_put_arg (ty, avalue[i], argp); } } static void ffi_prep_args_VFP (ffi_cif *cif, int flags, void *rvalue, void **avalue, char *stack, char *vfp_space) { ffi_type **arg_types = cif->arg_types; int i, n, vi = 0; char *argp, *regp, *eo_regp; char stack_used = 0; char done_with_regs = 0; /* The first 4 words on the stack are used for values passed in core registers. */ regp = stack; eo_regp = argp = regp + 16; /* If the function returns an FFI_TYPE_STRUCT in memory, that address is passed in r0 to the function. */ if (flags == ARM_TYPE_STRUCT) { *(void **) regp = rvalue; regp += 4; } for (i = 0, n = cif->nargs; i < n; i++) { ffi_type *ty = arg_types[i]; void *a = avalue[i]; int is_vfp_type = vfp_type_p (ty); /* Allocated in VFP registers. */ if (vi < cif->vfp_nargs && is_vfp_type) { char *vfp_slot = vfp_space + cif->vfp_args[vi++] * 4; ffi_put_arg (ty, a, vfp_slot); continue; } /* Try allocating in core registers. */ else if (!done_with_regs && !is_vfp_type) { char *tregp = ffi_align (ty, regp); size_t size = ty->size; size = (size < 4) ? 4 : size; // pad /* Check if there is space left in the aligned register area to place the argument. */ if (tregp + size <= eo_regp) { regp = tregp + ffi_put_arg (ty, a, tregp); done_with_regs = (regp == argp); // ensure we did not write into the stack area FFI_ASSERT (regp <= argp); continue; } /* In case there are no arguments in the stack area yet, the argument is passed in the remaining core registers and on the stack. */ else if (!stack_used) { stack_used = 1; done_with_regs = 1; argp = tregp + ffi_put_arg (ty, a, tregp); FFI_ASSERT (eo_regp < argp); continue; } } /* Base case, arguments are passed on the stack */ stack_used = 1; argp = ffi_align (ty, argp); argp += ffi_put_arg (ty, a, argp); } } /* Perform machine dependent cif processing */ ffi_status ffi_prep_cif_machdep (ffi_cif *cif) { int flags = 0, cabi = cif->abi; size_t bytes = cif->bytes; /* Map out the register placements of VFP register args. The VFP hard-float calling conventions are slightly more sophisticated than the base calling conventions, so we do it here instead of in ffi_prep_args(). */ if (cabi == FFI_VFP) layout_vfp_args (cif); /* Set the return type flag */ switch (cif->rtype->type) { case FFI_TYPE_VOID: flags = ARM_TYPE_VOID; break; case FFI_TYPE_INT: case FFI_TYPE_UINT8: case FFI_TYPE_SINT8: case FFI_TYPE_UINT16: case FFI_TYPE_SINT16: case FFI_TYPE_UINT32: case FFI_TYPE_SINT32: case FFI_TYPE_POINTER: flags = ARM_TYPE_INT; break; case FFI_TYPE_SINT64: case FFI_TYPE_UINT64: flags = ARM_TYPE_INT64; break; case FFI_TYPE_FLOAT: flags = (cabi == FFI_VFP ? ARM_TYPE_VFP_S : ARM_TYPE_INT); break; case FFI_TYPE_DOUBLE: flags = (cabi == FFI_VFP ? ARM_TYPE_VFP_D : ARM_TYPE_INT64); break; case FFI_TYPE_STRUCT: case FFI_TYPE_COMPLEX: if (cabi == FFI_VFP) { int h = vfp_type_p (cif->rtype); flags = ARM_TYPE_VFP_N; if (h == 0x100 + FFI_TYPE_FLOAT) flags = ARM_TYPE_VFP_S; if (h == 0x100 + FFI_TYPE_DOUBLE) flags = ARM_TYPE_VFP_D; if (h != 0) break; } /* A Composite Type not larger than 4 bytes is returned in r0. A Composite Type larger than 4 bytes, or whose size cannot be determined statically ... is stored in memory at an address passed [in r0]. */ if (cif->rtype->size <= 4) flags = ARM_TYPE_INT; else { flags = ARM_TYPE_STRUCT; bytes += 4; } break; default: abort(); } /* Round the stack up to a multiple of 8 bytes. This isn't needed everywhere, but it is on some platforms, and it doesn't harm anything when it isn't needed. */ bytes = ALIGN (bytes, 8); /* Minimum stack space is the 4 register arguments that we pop. */ if (bytes < 4*4) bytes = 4*4; cif->bytes = bytes; cif->flags = flags; return FFI_OK; } /* Perform machine dependent cif processing for variadic calls */ ffi_status ffi_prep_cif_machdep_var (ffi_cif * cif, unsigned int nfixedargs, unsigned int ntotalargs) { /* VFP variadic calls actually use the SYSV ABI */ if (cif->abi == FFI_VFP) cif->abi = FFI_SYSV; return ffi_prep_cif_machdep (cif); } /* Prototypes for assembly functions, in sysv.S. */ struct call_frame { void *fp; void *lr; void *rvalue; int flags; void *closure; }; extern void ffi_call_SYSV (void *stack, struct call_frame *, void (*fn) (void)) FFI_HIDDEN; extern void ffi_call_VFP (void *vfp_space, struct call_frame *, void (*fn) (void), unsigned vfp_used) FFI_HIDDEN; static void ffi_call_int (ffi_cif * cif, void (*fn) (void), void *rvalue, void **avalue, void *closure) { int flags = cif->flags; ffi_type *rtype = cif->rtype; size_t bytes, rsize, vfp_size; char *stack, *vfp_space, *new_rvalue; struct call_frame *frame; rsize = 0; if (rvalue == NULL) { /* If the return value is a struct and we don't have a return value address then we need to make one. Otherwise the return value is in registers and we can ignore them. */ if (flags == ARM_TYPE_STRUCT) rsize = rtype->size; else flags = ARM_TYPE_VOID; } else if (flags == ARM_TYPE_VFP_N) { /* Largest case is double x 4. */ rsize = 32; } else if (flags == ARM_TYPE_INT && rtype->type == FFI_TYPE_STRUCT) rsize = 4; /* Largest case. */ vfp_size = (cif->abi == FFI_VFP && cif->vfp_used ? 8*8: 0); bytes = cif->bytes; stack = alloca (vfp_size + bytes + sizeof(struct call_frame) + rsize); vfp_space = NULL; if (vfp_size) { vfp_space = stack; stack += vfp_size; } frame = (struct call_frame *)(stack + bytes); new_rvalue = rvalue; if (rsize) new_rvalue = (void *)(frame + 1); frame->rvalue = new_rvalue; frame->flags = flags; frame->closure = closure; if (vfp_space) { ffi_prep_args_VFP (cif, flags, new_rvalue, avalue, stack, vfp_space); ffi_call_VFP (vfp_space, frame, fn, cif->vfp_used); } else { ffi_prep_args_SYSV (cif, flags, new_rvalue, avalue, stack); ffi_call_SYSV (stack, frame, fn); } if (rvalue && rvalue != new_rvalue) memcpy (rvalue, new_rvalue, rtype->size); } void ffi_call (ffi_cif *cif, void (*fn) (void), void *rvalue, void **avalue) { ffi_call_int (cif, fn, rvalue, avalue, NULL); } void ffi_call_go (ffi_cif *cif, void (*fn) (void), void *rvalue, void **avalue, void *closure) { ffi_call_int (cif, fn, rvalue, avalue, closure); } static void * ffi_prep_incoming_args_SYSV (ffi_cif *cif, void *rvalue, char *argp, void **avalue) { ffi_type **arg_types = cif->arg_types; int i, n; if (cif->flags == ARM_TYPE_STRUCT) { rvalue = *(void **) argp; argp += 4; } for (i = 0, n = cif->nargs; i < n; i++) { ffi_type *ty = arg_types[i]; size_t z = ty->size; argp = ffi_align (ty, argp); avalue[i] = (void *) argp; argp += z; } return rvalue; } static void * ffi_prep_incoming_args_VFP (ffi_cif *cif, void *rvalue, char *stack, char *vfp_space, void **avalue) { ffi_type **arg_types = cif->arg_types; int i, n, vi = 0; char *argp, *regp, *eo_regp; char done_with_regs = 0; char stack_used = 0; regp = stack; eo_regp = argp = regp + 16; if (cif->flags == ARM_TYPE_STRUCT) { rvalue = *(void **) regp; regp += 4; } for (i = 0, n = cif->nargs; i < n; i++) { ffi_type *ty = arg_types[i]; int is_vfp_type = vfp_type_p (ty); size_t z = ty->size; if (vi < cif->vfp_nargs && is_vfp_type) { avalue[i] = vfp_space + cif->vfp_args[vi++] * 4; continue; } else if (!done_with_regs && !is_vfp_type) { char *tregp = ffi_align (ty, regp); z = (z < 4) ? 4 : z; // pad /* If the arguments either fits into the registers or uses registers and stack, while we haven't read other things from the stack */ if (tregp + z <= eo_regp || !stack_used) { /* Because we're little endian, this is what it turns into. */ avalue[i] = (void *) tregp; regp = tregp + z; /* If we read past the last core register, make sure we have not read from the stack before and continue reading after regp. */ if (regp > eo_regp) { FFI_ASSERT (!stack_used); argp = regp; } if (regp >= eo_regp) { done_with_regs = 1; stack_used = 1; } continue; } } stack_used = 1; argp = ffi_align (ty, argp); avalue[i] = (void *) argp; argp += z; } return rvalue; } struct closure_frame { char vfp_space[8*8] __attribute__((aligned(8))); char result[8*4]; char argp[]; }; int FFI_HIDDEN ffi_closure_inner_SYSV (ffi_cif *cif, void (*fun) (ffi_cif *, void *, void **, void *), void *user_data, struct closure_frame *frame) { void **avalue = (void **) alloca (cif->nargs * sizeof (void *)); void *rvalue = ffi_prep_incoming_args_SYSV (cif, frame->result, frame->argp, avalue); fun (cif, rvalue, avalue, user_data); return cif->flags; } int FFI_HIDDEN ffi_closure_inner_VFP (ffi_cif *cif, void (*fun) (ffi_cif *, void *, void **, void *), void *user_data, struct closure_frame *frame) { void **avalue = (void **) alloca (cif->nargs * sizeof (void *)); void *rvalue = ffi_prep_incoming_args_VFP (cif, frame->result, frame->argp, frame->vfp_space, avalue); fun (cif, rvalue, avalue, user_data); return cif->flags; } void ffi_closure_SYSV (void) FFI_HIDDEN; void ffi_closure_VFP (void) FFI_HIDDEN; void ffi_go_closure_SYSV (void) FFI_HIDDEN; void ffi_go_closure_VFP (void) FFI_HIDDEN; /* the cif must already be prep'ed */ ffi_status ffi_prep_closure_loc (ffi_closure * closure, ffi_cif * cif, void (*fun) (ffi_cif *, void *, void **, void *), void *user_data, void *codeloc) { void (*closure_func) (void) = ffi_closure_SYSV; if (cif->abi == FFI_VFP) { /* We only need take the vfp path if there are vfp arguments. */ if (cif->vfp_used) closure_func = ffi_closure_VFP; } else if (cif->abi != FFI_SYSV) return FFI_BAD_ABI; #if FFI_EXEC_TRAMPOLINE_TABLE void **config = (void **)((uint8_t *)codeloc - PAGE_MAX_SIZE); config[0] = closure; config[1] = closure_func; #else memcpy (closure->tramp, ffi_arm_trampoline, 8); __clear_cache(closure->tramp, closure->tramp + 8); /* clear data map */ __clear_cache(codeloc, codeloc + 8); /* clear insn map */ *(void (**)(void))(closure->tramp + 8) = closure_func; #endif closure->cif = cif; closure->fun = fun; closure->user_data = user_data; return FFI_OK; } ffi_status ffi_prep_go_closure (ffi_go_closure *closure, ffi_cif *cif, void (*fun) (ffi_cif *, void *, void **, void *)) { void (*closure_func) (void) = ffi_go_closure_SYSV; if (cif->abi == FFI_VFP) { /* We only need take the vfp path if there are vfp arguments. */ if (cif->vfp_used) closure_func = ffi_go_closure_VFP; } else if (cif->abi != FFI_SYSV) return FFI_BAD_ABI; closure->tramp = closure_func; closure->cif = cif; closure->fun = fun; return FFI_OK; } /* Below are routines for VFP hard-float support. */ /* A subroutine of vfp_type_p. Given a structure type, return the type code of the first non-structure element. Recurse for structure elements. Return -1 if the structure is in fact empty, i.e. no nested elements. */ static int is_hfa0 (const ffi_type *ty) { ffi_type **elements = ty->elements; int i, ret = -1; if (elements != NULL) for (i = 0; elements[i]; ++i) { ret = elements[i]->type; if (ret == FFI_TYPE_STRUCT || ret == FFI_TYPE_COMPLEX) { ret = is_hfa0 (elements[i]); if (ret < 0) continue; } break; } return ret; } /* A subroutine of vfp_type_p. Given a structure type, return true if all of the non-structure elements are the same as CANDIDATE. */ static int is_hfa1 (const ffi_type *ty, int candidate) { ffi_type **elements = ty->elements; int i; if (elements != NULL) for (i = 0; elements[i]; ++i) { int t = elements[i]->type; if (t == FFI_TYPE_STRUCT || t == FFI_TYPE_COMPLEX) { if (!is_hfa1 (elements[i], candidate)) return 0; } else if (t != candidate) return 0; } return 1; } /* Determine if TY is an homogenous floating point aggregate (HFA). That is, a structure consisting of 1 to 4 members of all the same type, where that type is a floating point scalar. Returns non-zero iff TY is an HFA. The result is an encoded value where bits 0-7 contain the type code, and bits 8-10 contain the element count. */ static int vfp_type_p (const ffi_type *ty) { ffi_type **elements; int candidate, i; size_t size, ele_count; /* Quickest tests first. */ candidate = ty->type; switch (ty->type) { default: return 0; case FFI_TYPE_FLOAT: case FFI_TYPE_DOUBLE: ele_count = 1; goto done; case FFI_TYPE_COMPLEX: candidate = ty->elements[0]->type; if (candidate != FFI_TYPE_FLOAT && candidate != FFI_TYPE_DOUBLE) return 0; ele_count = 2; goto done; case FFI_TYPE_STRUCT: break; } /* No HFA types are smaller than 4 bytes, or larger than 32 bytes. */ size = ty->size; if (size < 4 || size > 32) return 0; /* Find the type of the first non-structure member. */ elements = ty->elements; candidate = elements[0]->type; if (candidate == FFI_TYPE_STRUCT || candidate == FFI_TYPE_COMPLEX) { for (i = 0; ; ++i) { candidate = is_hfa0 (elements[i]); if (candidate >= 0) break; } } /* If the first member is not a floating point type, it's not an HFA. Also quickly re-check the size of the structure. */ switch (candidate) { case FFI_TYPE_FLOAT: ele_count = size / sizeof(float); if (size != ele_count * sizeof(float)) return 0; break; case FFI_TYPE_DOUBLE: ele_count = size / sizeof(double); if (size != ele_count * sizeof(double)) return 0; break; default: return 0; } if (ele_count > 4) return 0; /* Finally, make sure that all scalar elements are the same type. */ for (i = 0; elements[i]; ++i) { int t = elements[i]->type; if (t == FFI_TYPE_STRUCT || t == FFI_TYPE_COMPLEX) { if (!is_hfa1 (elements[i], candidate)) return 0; } else if (t != candidate) return 0; } /* All tests succeeded. Encode the result. */ done: return (ele_count << 8) | candidate; } static int place_vfp_arg (ffi_cif *cif, int h) { unsigned short reg = cif->vfp_reg_free; int align = 1, nregs = h >> 8; if ((h & 0xff) == FFI_TYPE_DOUBLE) align = 2, nregs *= 2; /* Align register number. */ if ((reg & 1) && align == 2) reg++; while (reg + nregs <= 16) { int s, new_used = 0; for (s = reg; s < reg + nregs; s++) { new_used |= (1 << s); if (cif->vfp_used & (1 << s)) { reg += align; goto next_reg; } } /* Found regs to allocate. */ cif->vfp_used |= new_used; cif->vfp_args[cif->vfp_nargs++] = reg; /* Update vfp_reg_free. */ if (cif->vfp_used & (1 << cif->vfp_reg_free)) { reg += nregs; while (cif->vfp_used & (1 << reg)) reg += 1; cif->vfp_reg_free = reg; } return 0; next_reg:; } // done, mark all regs as used cif->vfp_reg_free = 16; cif->vfp_used = 0xFFFF; return 1; } static void layout_vfp_args (ffi_cif * cif) { int i; /* Init VFP fields */ cif->vfp_used = 0; cif->vfp_nargs = 0; cif->vfp_reg_free = 0; memset (cif->vfp_args, -1, 16); /* Init to -1. */ for (i = 0; i < cif->nargs; i++) { int h = vfp_type_p (cif->arg_types[i]); if (h && place_vfp_arg (cif, h) == 1) break; } }