1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6 /* Platform specific code to invoke XPCOM methods on native objects */
7
8 #include "xptcprivate.h"
9
10 // Remember that these 'words' are 32bit DWORDS
11
12 static uint32_t
invoke_count_words(uint32_t paramCount,nsXPTCVariant * s)13 invoke_count_words(uint32_t paramCount, nsXPTCVariant* s)
14 {
15 uint32_t result = 0;
16 for(uint32_t i = 0; i < paramCount; i++, s++)
17 {
18 if(s->IsPtrData())
19 {
20 result++;
21 continue;
22 }
23 switch(s->type)
24 {
25 case nsXPTType::T_I8 :
26 case nsXPTType::T_I16 :
27 case nsXPTType::T_I32 :
28 result++;
29 break;
30 case nsXPTType::T_I64 :
31 result+=2;
32 break;
33 case nsXPTType::T_U8 :
34 case nsXPTType::T_U16 :
35 case nsXPTType::T_U32 :
36 result++;
37 break;
38 case nsXPTType::T_U64 :
39 result+=2;
40 break;
41 case nsXPTType::T_FLOAT :
42 result++;
43 break;
44 case nsXPTType::T_DOUBLE :
45 result+=2;
46 break;
47 case nsXPTType::T_BOOL :
48 case nsXPTType::T_CHAR :
49 case nsXPTType::T_WCHAR :
50 result++;
51 break;
52 default:
53 // all the others are plain pointer types
54 result++;
55 break;
56 }
57 }
58 return result;
59 }
60
61 static void
invoke_copy_to_stack(uint32_t * d,uint32_t paramCount,nsXPTCVariant * s)62 invoke_copy_to_stack(uint32_t* d, uint32_t paramCount, nsXPTCVariant* s)
63 {
64 for(uint32_t i = 0; i < paramCount; i++, d++, s++)
65 {
66 if(s->IsPtrData())
67 {
68 *((void**)d) = s->ptr;
69 continue;
70 }
71 switch(s->type)
72 {
73 case nsXPTType::T_I8 : *((int8_t*) d) = s->val.i8; break;
74 case nsXPTType::T_I16 : *((int16_t*) d) = s->val.i16; break;
75 case nsXPTType::T_I32 : *((int32_t*) d) = s->val.i32; break;
76 case nsXPTType::T_I64 : *((int64_t*) d) = s->val.i64; d++; break;
77 case nsXPTType::T_U8 : *((uint8_t*) d) = s->val.u8; break;
78 case nsXPTType::T_U16 : *((uint16_t*)d) = s->val.u16; break;
79 case nsXPTType::T_U32 : *((uint32_t*)d) = s->val.u32; break;
80 case nsXPTType::T_U64 : *((uint64_t*)d) = s->val.u64; d++; break;
81 case nsXPTType::T_FLOAT : *((float*) d) = s->val.f; break;
82 case nsXPTType::T_DOUBLE : *((double*) d) = s->val.d; d++; break;
83 case nsXPTType::T_BOOL : *((bool*) d) = s->val.b; break;
84 case nsXPTType::T_CHAR : *((char*) d) = s->val.c; break;
85 case nsXPTType::T_WCHAR : *((wchar_t*) d) = s->val.wc; break;
86 default:
87 // all the others are plain pointer types
88 *((void**)d) = s->val.p;
89 break;
90 }
91 }
92 }
93
94 extern "C" {
95 struct my_params_struct {
96 nsISupports* that;
97 uint32_t Index;
98 uint32_t Count;
99 nsXPTCVariant* params;
100 uint32_t fn_count;
101 uint32_t fn_copy;
102 };
103 }
104
105 EXPORT_XPCOM_API(nsresult)
NS_InvokeByIndex(nsISupports * that,uint32_t methodIndex,uint32_t paramCount,nsXPTCVariant * params)106 NS_InvokeByIndex(nsISupports* that, uint32_t methodIndex,
107 uint32_t paramCount, nsXPTCVariant* params)
108 {
109 uint32_t result;
110 struct my_params_struct my_params;
111 my_params.that = that;
112 my_params.Index = methodIndex;
113 my_params.Count = paramCount;
114 my_params.params = params;
115 my_params.fn_copy = (uint32_t) &invoke_copy_to_stack;
116 my_params.fn_count = (uint32_t) &invoke_count_words;
117
118 /* This is to call a given method of class that.
119 * The parameters are in params, the number is in paramCount.
120 * The routine will issue calls to count the number of words
121 * required for argument passing and to copy the arguments to
122 * the stack.
123 * Since APCS passes the first 3 params in r1-r3, we need to
124 * load the first three words from the stack and correct the stack
125 * pointer (sp) in the appropriate way. This means:
126 *
127 * 1.) more than 3 arguments: load r1-r3, correct sp and remember No.
128 * of bytes left on the stack in r4
129 *
130 * 2.) <= 2 args: load r1-r3 (we won't be causing a stack overflow I hope),
131 * restore sp as if nothing had happened and set the marker r4 to zero.
132 *
133 * Afterwards sp will be restored using the value in r4 (which is not a temporary register
134 * and will be preserved by the function/method called according to APCS [ARM Procedure
135 * Calling Standard]).
136 *
137 * !!! IMPORTANT !!!
138 * This routine makes assumptions about the vtable layout of the c++ compiler. It's implemented
139 * for arm-linux GNU g++ >= 2.8.1 (including egcs and gcc-2.95.[1-3])!
140 *
141 */
142
143 #ifdef __GNUC__
144 __asm__ __volatile__(
145 "ldr r1, [%1, #12] \n\t" /* prepare to call invoke_count_words */
146 "ldr ip, [%1, #16] \n\t" /* r0=paramCount, r1=params */
147 "ldr r0, [%1, #8] \n\t"
148 "mov lr, pc \n\t" /* call it... */
149 "mov pc, ip \n\t"
150 "mov r4, r0, lsl #2 \n\t" /* This is the amount of bytes needed. */
151 "sub sp, sp, r4 \n\t" /* use stack space for the args... */
152 "mov r0, sp \n\t" /* prepare a pointer an the stack */
153 "ldr r1, [%1, #8] \n\t" /* =paramCount */
154 "ldr r2, [%1, #12] \n\t" /* =params */
155 "ldr ip, [%1, #20] \n\t" /* =invoke_copy_to_stack */
156 "mov lr, pc \n\t" /* copy args to the stack like the */
157 "mov pc, ip \n\t" /* compiler would. */
158 "ldr r0, [%1] \n\t" /* =that */
159 "ldr r1, [r0, #0] \n\t" /* get that->vtable offset */
160 "ldr r2, [%1, #4] \n\t"
161 "mov r2, r2, lsl #2 \n\t" /* a vtable_entry(x)=8 + (4 bytes * x) */
162 "ldr ip, [r1, r2] \n\t" /* get method adress from vtable */
163 "cmp r4, #12 \n\t" /* more than 3 arguments??? */
164 "ldmgtia sp!, {r1, r2, r3}\n\t" /* yes: load arguments for r1-r3 */
165 "subgt r4, r4, #12 \n\t" /* and correct the stack pointer */
166 "ldmleia sp, {r1, r2, r3}\n\t" /* no: load r1-r3 from stack */
167 "addle sp, sp, r4 \n\t" /* and restore stack pointer */
168 "movle r4, #0 \n\t" /* a mark for restoring sp */
169 "ldr r0, [%1, #0] \n\t" /* get (self) */
170 "mov lr, pc \n\t" /* call mathod */
171 "mov pc, ip \n\t"
172 "add sp, sp, r4 \n\t" /* restore stack pointer */
173 "mov %0, r0 \n\t" /* the result... */
174 : "=r" (result)
175 : "r" (&my_params), "m" (my_params)
176 : "r0", "r1", "r2", "r3", "r4", "ip", "lr", "sp"
177 );
178 #else
179 #error "Unsupported compiler. Use g++ >= 2.8 for OpenBSD/arm."
180 #endif /* G++ >= 2.8 */
181
182 return result;
183 }
184