1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// Platform specific code to invoke XPCOM methods on native objects
#include "xptcprivate.h"
// 6 integral parameters are passed in registers
const uint32_t GPR_COUNT = 6;
// 8 floating point parameters are passed in SSE registers
const uint32_t FPR_COUNT = 8;
// Remember that these 'words' are 64-bit long
static inline void
invoke_count_words(uint32_t paramCount, nsXPTCVariant * s,
uint32_t & nr_stack)
{
uint32_t nr_gpr;
uint32_t nr_fpr;
nr_gpr = 1; // skip one GP register for 'that'
nr_fpr = 0;
nr_stack = 0;
/* Compute number of eightbytes of class MEMORY. */
for (uint32_t i = 0; i < paramCount; i++, s++) {
if (!s->IsPtrData()
&& (s->type == nsXPTType::T_FLOAT || s->type == nsXPTType::T_DOUBLE)) {
if (nr_fpr < FPR_COUNT)
nr_fpr++;
else
nr_stack++;
}
else {
if (nr_gpr < GPR_COUNT)
nr_gpr++;
else
nr_stack++;
}
}
}
static void
invoke_copy_to_stack(uint64_t * d, uint32_t paramCount, nsXPTCVariant * s,
uint64_t * gpregs, double * fpregs)
{
uint32_t nr_gpr = 1u; // skip one GP register for 'that'
uint32_t nr_fpr = 0u;
uint64_t value = 0u;
for (uint32_t i = 0; i < paramCount; i++, s++) {
if (s->IsPtrData())
value = (uint64_t) s->ptr;
else {
switch (s->type) {
case nsXPTType::T_FLOAT: break;
case nsXPTType::T_DOUBLE: break;
case nsXPTType::T_I8: value = s->val.i8; break;
case nsXPTType::T_I16: value = s->val.i16; break;
case nsXPTType::T_I32: value = s->val.i32; break;
case nsXPTType::T_I64: value = s->val.i64; break;
case nsXPTType::T_U8: value = s->val.u8; break;
case nsXPTType::T_U16: value = s->val.u16; break;
case nsXPTType::T_U32: value = s->val.u32; break;
case nsXPTType::T_U64: value = s->val.u64; break;
case nsXPTType::T_BOOL: value = s->val.b; break;
case nsXPTType::T_CHAR: value = s->val.c; break;
case nsXPTType::T_WCHAR: value = s->val.wc; break;
default: value = (uint64_t) s->val.p; break;
}
}
if (!s->IsPtrData() && s->type == nsXPTType::T_DOUBLE) {
if (nr_fpr < FPR_COUNT)
fpregs[nr_fpr++] = s->val.d;
else {
*((double *)d) = s->val.d;
d++;
}
}
else if (!s->IsPtrData() && s->type == nsXPTType::T_FLOAT) {
if (nr_fpr < FPR_COUNT)
// The value in %xmm register is already prepared to
// be retrieved as a float. Therefore, we pass the
// value verbatim, as a double without conversion.
fpregs[nr_fpr++] = s->val.d;
else {
*((float *)d) = s->val.f;
d++;
}
}
else {
if (nr_gpr < GPR_COUNT)
gpregs[nr_gpr++] = value;
else
*d++ = value;
}
}
}
// Disable avx for the next function to allow compilation with
// -march=native on new machines, or similar hardcoded -march options.
// Having avx enabled appears to change the alignment behavior of alloca
// (apparently adding an extra 16 bytes) of padding/alignment (and using
// 32-byte alignment instead of 16-byte). This seems to be the best
// available workaround, given that this code, which should perhaps
// better be written in assembly, is written in C++.
#ifndef __clang__
#pragma GCC push_options
#pragma GCC target ("no-avx")
#endif
// Avoid AddressSanitizer instrumentation for the next function because it
// depends on __builtin_alloca behavior and alignment that cannot be relied on
// once the function is compiled with a version of ASan that has dynamic-alloca
// instrumentation enabled.
MOZ_ASAN_BLACKLIST
EXPORT_XPCOM_API(nsresult)
NS_InvokeByIndex(nsISupports * that, uint32_t methodIndex,
uint32_t paramCount, nsXPTCVariant * params)
{
uint32_t nr_stack;
invoke_count_words(paramCount, params, nr_stack);
// Stack, if used, must be 16-bytes aligned
if (nr_stack)
nr_stack = (nr_stack + 1) & ~1;
// Load parameters to stack, if necessary
uint64_t *stack = (uint64_t *) __builtin_alloca(nr_stack * 8);
uint64_t gpregs[GPR_COUNT];
double fpregs[FPR_COUNT];
invoke_copy_to_stack(stack, paramCount, params, gpregs, fpregs);
// We used to have switches to make sure we would only load the registers
// that are needed for this call. That produced larger code that was
// not faster in practice. It also caused compiler warnings about the
// variables being used uninitialized.
// We now just load every every register. There could still be a warning
// from a memory analysis tools that we are loading uninitialized stack
// positions.
// FIXME: this function depends on the above __builtin_alloca placing
// the array in the correct spot for the ABI.
// Load FPR registers from fpregs[]
double d0, d1, d2, d3, d4, d5, d6, d7;
d7 = fpregs[7];
d6 = fpregs[6];
d5 = fpregs[5];
d4 = fpregs[4];
d3 = fpregs[3];
d2 = fpregs[2];
d1 = fpregs[1];
d0 = fpregs[0];
// Load GPR registers from gpregs[]
uint64_t a0, a1, a2, a3, a4, a5;
a5 = gpregs[5];
a4 = gpregs[4];
a3 = gpregs[3];
a2 = gpregs[2];
a1 = gpregs[1];
a0 = (uint64_t) that;
// Get pointer to method
uint64_t methodAddress = *((uint64_t *)that);
methodAddress += 8 * methodIndex;
methodAddress = *((uint64_t *)methodAddress);
typedef nsresult (*Method)(uint64_t, uint64_t, uint64_t, uint64_t,
uint64_t, uint64_t, double, double, double,
double, double, double, double, double);
nsresult result = ((Method)methodAddress)(a0, a1, a2, a3, a4, a5,
d0, d1, d2, d3, d4, d5,
d6, d7);
return result;
}
#ifndef __clang__
#pragma GCC pop_options
#endif
|
