/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ /* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is mozilla.org code. * * The Initial Developer of the Original Code is * Netscape Communications Corporation. * Portions created by the Initial Developer are Copyright (C) 1998 * the Initial Developer. All Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the terms of * either of the GNU General Public License Version 2 or later (the "GPL"), * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ /* Platform specific code to invoke XPCOM methods on native objects */ #include "prlog.h" #include "xptcprivate.h" #if !defined(LINUX) || !defined(__arm__) #error "This code is for Linux ARM only. Check that it works on your system, too.\nBeware that this code is highly compiler dependent." #endif /* Note that we give a "worst case" estimate of how much stack _might_ be * needed (for __ARM_EABI__), rather than the real count - this should be safe */ #ifdef __ARM_EABI__ #define DOUBLEWORD_ALIGN(p) ((PRUint32 *)((((PRUint32)(p)) + 7) & 0xfffffff8)) #define VAR_STACK_SIZE_64 3 #else #define DOUBLEWORD_ALIGN(p) (p) #define VAR_STACK_SIZE_64 2 #endif // Remember that these 'words' are 32bit DWORDS static PRUint32 invoke_count_words(PRUint32 paramCount, nsXPTCVariant* s) { PRUint32 result = 0; for(PRUint32 i = 0; i < paramCount; i++, s++) { if(s->IsPtrData()) { result++; continue; } switch(s->type) { case nsXPTType::T_I8 : case nsXPTType::T_I16 : case nsXPTType::T_I32 : result++; break; case nsXPTType::T_I64 : result+=VAR_STACK_SIZE_64; break; case nsXPTType::T_U8 : case nsXPTType::T_U16 : case nsXPTType::T_U32 : result++; break; case nsXPTType::T_U64 : result+=VAR_STACK_SIZE_64; break; case nsXPTType::T_FLOAT : result++; break; case nsXPTType::T_DOUBLE : result+=VAR_STACK_SIZE_64; break; case nsXPTType::T_BOOL : case nsXPTType::T_CHAR : case nsXPTType::T_WCHAR : result++; break; default: // all the others are plain pointer types result++; break; } } #ifdef __ARM_EABI__ /* Ensure stack is always aligned to doubleword boundary; we take 3 words * off the stack to r1-r3 later, so it must always be on _odd_ word * boundary after this */ if (result % 2 == 0) result++; #endif return result; } static void invoke_copy_to_stack(PRUint32* d, PRUint32 paramCount, nsXPTCVariant* s) { for(PRUint32 i = 0; i < paramCount; i++, d++, s++) { if(s->IsPtrData()) { *((void**)d) = s->ptr; continue; } // According to the ARM EABI, integral types that are smaller than a word // are to be sign/zero-extended to a full word and treated as 4-byte values. // NOTE: on ARM/gcc, char is unsigned by default, and PRunichar is unisgned. PR_STATIC_ASSERT(char(0xFF) == PRUint32(0xFF)); PR_STATIC_ASSERT(PRUnichar(0xFFFF) == PRUint32(0xFFFF)); switch(s->type) { case nsXPTType::T_I8 : *((PRInt32*) d) = s->val.i8; break; case nsXPTType::T_I16 : *((PRInt32*) d) = s->val.i16; break; case nsXPTType::T_I32 : *((PRInt32*) d) = s->val.i32; break; case nsXPTType::T_I64 : d = DOUBLEWORD_ALIGN(d); *((PRInt64*) d) = s->val.i64; d++; break; case nsXPTType::T_U8 : *((PRUint32*)d) = s->val.u8; break; case nsXPTType::T_U16 : *((PRUint32*)d) = s->val.u16; break; case nsXPTType::T_U32 : *((PRUint32*)d) = s->val.u32; break; case nsXPTType::T_U64 : d = DOUBLEWORD_ALIGN(d); *((PRUint64*)d) = s->val.u64; d++; break; case nsXPTType::T_FLOAT : *((float*) d) = s->val.f; break; case nsXPTType::T_DOUBLE : d = DOUBLEWORD_ALIGN(d); *((double*) d) = s->val.d; d++; break; case nsXPTType::T_BOOL : *((PRInt32*) d) = s->val.b; break; case nsXPTType::T_CHAR : *((PRUint32*)d) = s->val.c; break; case nsXPTType::T_WCHAR : *((PRUint32*)d) = s->val.wc; break; default: // all the others are plain pointer types *((void**)d) = s->val.p; break; } } } extern "C" { struct my_params_struct { nsISupports* that; PRUint32 Index; PRUint32 Count; nsXPTCVariant* params; PRUint32 fn_count; PRUint32 fn_copy; }; } EXPORT_XPCOM_API(nsresult) NS_InvokeByIndex(nsISupports* that, PRUint32 methodIndex, PRUint32 paramCount, nsXPTCVariant* params) { PRUint32 result; struct my_params_struct my_params; my_params.that = that; my_params.Index = methodIndex; my_params.Count = paramCount; my_params.params = params; my_params.fn_copy = (PRUint32) &invoke_copy_to_stack; my_params.fn_count = (PRUint32) &invoke_count_words; /* This is to call a given method of class that. * The parameters are in params, the number is in paramCount. * The routine will issue calls to count the number of words * required for argument passing and to copy the arguments to * the stack. * Since APCS passes the first 3 params in r1-r3, we need to * load the first three words from the stack and correct the stack * pointer (sp) in the appropriate way. This means: * * 1.) more than 3 arguments: load r1-r3, correct sp and remember No. * of bytes left on the stack in r4 * * 2.) <= 2 args: load r1-r3 (we won't be causing a stack overflow I hope), * restore sp as if nothing had happened and set the marker r4 to zero. * * Afterwards sp will be restored using the value in r4 (which is not a temporary register * and will be preserved by the function/method called according to APCS [ARM Procedure * Calling Standard]). * * !!! IMPORTANT !!! * This routine makes assumptions about the vtable layout of the c++ compiler. It's implemented * for arm-linux GNU g++ >= 2.8.1 (including egcs and gcc-2.95.[1-3])! * */ __asm__ __volatile__( "ldr r1, [%1, #12] \n\t" /* prepare to call invoke_count_words */ "ldr ip, [%1, #16] \n\t" /* r0=paramCount, r1=params */ "ldr r0, [%1, #8] \n\t" "mov lr, pc \n\t" /* call it... */ "mov pc, ip \n\t" "mov r4, r0, lsl #2 \n\t" /* This is the amount of bytes needed. */ "sub sp, sp, r4 \n\t" /* use stack space for the args... */ "mov r0, sp \n\t" /* prepare a pointer an the stack */ "ldr r1, [%1, #8] \n\t" /* =paramCount */ "ldr r2, [%1, #12] \n\t" /* =params */ "ldr ip, [%1, #20] \n\t" /* =invoke_copy_to_stack */ "mov lr, pc \n\t" /* copy args to the stack like the */ "mov pc, ip \n\t" /* compiler would. */ "ldr r0, [%1] \n\t" /* =that */ "ldr r1, [r0, #0] \n\t" /* get that->vtable offset */ "ldr r2, [%1, #4] \n\t" "mov r2, r2, lsl #2 \n\t" /* a vtable_entry(x)=8 + (4 bytes * x) */ #if defined(__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100 /* G++ V3 ABI */ "ldr ip, [r1, r2] \n\t" /* get method adress from vtable */ #else /* non G++ V3 ABI */ "add r2, r2, #8 \n\t" /* with this compilers */ "ldr ip, [r1, r2] \n\t" /* get method adress from vtable */ #endif "cmp r4, #12 \n\t" /* more than 3 arguments??? */ "ldmgtia sp!, {r1, r2, r3}\n\t" /* yes: load arguments for r1-r3 */ "subgt r4, r4, #12 \n\t" /* and correct the stack pointer */ "ldmleia sp, {r1, r2, r3}\n\t" /* no: load r1-r3 from stack */ "addle sp, sp, r4 \n\t" /* and restore stack pointer */ "movle r4, #0 \n\t" /* a mark for restoring sp */ "ldr r0, [%1, #0] \n\t" /* get (self) */ "mov lr, pc \n\t" /* call mathod */ "mov pc, ip \n\t" "add sp, sp, r4 \n\t" /* restore stack pointer */ "mov %0, r0 \n\t" /* the result... */ : "=r" (result) : "r" (&my_params), "m" (my_params) : "r0", "r1", "r2", "r3", "r4", "ip", "lr", "sp" ); return result; }