summaryrefslogtreecommitdiffstats
path: root/third_party/rust/httparse/src/simd/mod.rs
blob: b1cd85ce09bf8f6e25ae4b412c58fad509ce8016 (plain)
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
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
#[cfg(not(all(
    httparse_simd,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
)))]
mod fallback;

#[cfg(not(all(
    httparse_simd,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
)))]
pub use self::fallback::*;

#[cfg(all(
    httparse_simd,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
mod sse42;

#[cfg(all(
    httparse_simd,
    any(
        httparse_simd_target_feature_avx2,
        not(httparse_simd_target_feature_sse42),
    ),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
mod avx2;

#[cfg(all(
    httparse_simd,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub const SSE_42: usize = 1;
#[cfg(all(
    httparse_simd,
    any(not(httparse_simd_target_feature_sse42), httparse_simd_target_feature_avx2),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub const AVX_2: usize = 2;
#[cfg(all(
    httparse_simd,
    any(
        not(httparse_simd_target_feature_sse42),
        httparse_simd_target_feature_avx2,
        test,
    ),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub const AVX_2_AND_SSE_42: usize = 3;

#[cfg(all(
    httparse_simd,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
const NONE: usize = std::usize::MAX;
#[cfg(all(
    httparse_simd,
    not(any(
        httparse_simd_target_feature_sse42,
        httparse_simd_target_feature_avx2,
    )),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
mod runtime {
    //! Runtime detection of simd features. Used when the build script
    //! doesn't notice any target features at build time.
    //!
    //! While `is_x86_feature_detected!` has it's own caching built-in,
    //! at least in 1.27.0, the functions don't inline, leaving using it
    //! actually *slower* than just using the scalar fallback.

    use core::sync::atomic::{AtomicUsize, Ordering};

    static FEATURE: AtomicUsize = AtomicUsize::new(0);

    const INIT: usize = 0;

    pub fn detect() -> usize {
        let feat = FEATURE.load(Ordering::Relaxed);
        if feat == INIT {
            if cfg!(target_arch = "x86_64") && is_x86_feature_detected!("avx2") {
                if is_x86_feature_detected!("sse4.2") {
                    FEATURE.store(super::AVX_2_AND_SSE_42, Ordering::Relaxed);
                    return super::AVX_2_AND_SSE_42;
                } else {
                    FEATURE.store(super::AVX_2, Ordering::Relaxed);
                    return super::AVX_2;
                }
            } else if is_x86_feature_detected!("sse4.2") {
                FEATURE.store(super::SSE_42, Ordering::Relaxed);
                return super::SSE_42;
            } else {
                FEATURE.store(super::NONE, Ordering::Relaxed);
            }
        }
        feat
    }

    pub fn match_uri_vectored(bytes: &mut crate::iter::Bytes) {
        unsafe {
            match detect() {
                super::SSE_42 => super::sse42::parse_uri_batch_16(bytes),
                super::AVX_2 => { super::avx2::parse_uri_batch_32(bytes); },
                super::AVX_2_AND_SSE_42 => {
                    if let super::avx2::Scan::Found = super::avx2::parse_uri_batch_32(bytes) {
                        return;
                    }
                    super::sse42::parse_uri_batch_16(bytes)
                },
                _ => ()
            }
        }

        // else do nothing
    }

    pub fn match_header_value_vectored(bytes: &mut crate::iter::Bytes) {
        unsafe {
            match detect() {
                super::SSE_42 => super::sse42::match_header_value_batch_16(bytes),
                super::AVX_2 => { super::avx2::match_header_value_batch_32(bytes); },
                super::AVX_2_AND_SSE_42 => {
                    if let super::avx2::Scan::Found = super::avx2::match_header_value_batch_32(bytes) {
                        return;
                    }
                    super::sse42::match_header_value_batch_16(bytes)
                },
                _ => ()
            }
        }

        // else do nothing
    }
}

#[cfg(all(
    httparse_simd,
    not(any(
        httparse_simd_target_feature_sse42,
        httparse_simd_target_feature_avx2,
    )),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub use self::runtime::*;

#[cfg(all(
    httparse_simd,
    httparse_simd_target_feature_sse42,
    not(httparse_simd_target_feature_avx2),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
mod sse42_compile_time {
    pub fn match_uri_vectored(bytes: &mut crate::iter::Bytes) {
        if detect() == super::SSE_42 {
            unsafe {
                super::sse42::parse_uri_batch_16(bytes);
            }
        }

        // else do nothing
    }

    pub fn match_header_value_vectored(bytes: &mut crate::iter::Bytes) {
        if detect() == super::SSE_42 {
            unsafe {
                super::sse42::match_header_value_batch_16(bytes);
            }
        }

        // else do nothing
    }

    pub fn detect() -> usize {
        if is_x86_feature_detected!("sse4.2") {
            super::SSE_42
        } else {
            super::NONE
        }
    }
}

#[cfg(all(
    httparse_simd,
    httparse_simd_target_feature_sse42,
    not(httparse_simd_target_feature_avx2),
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub use self::sse42_compile_time::*;

#[cfg(all(
    httparse_simd,
    httparse_simd_target_feature_avx2,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
mod avx2_compile_time {
    pub fn match_uri_vectored(bytes: &mut crate::iter::Bytes) {
        // do both, since avx2 only works when bytes.len() >= 32
        if detect() == super::AVX_2_AND_SSE_42 {
            unsafe {
                super::avx2::parse_uri_batch_32(bytes);
            }

        } 
        if detect() == super::SSE_42 {
            unsafe {
                super::sse42::parse_uri_batch_16(bytes);
            }
        }

        // else do nothing
    }

    pub fn match_header_value_vectored(bytes: &mut crate::iter::Bytes) {
        // do both, since avx2 only works when bytes.len() >= 32
        if detect() == super::AVX_2_AND_SSE_42 {
            let scanned = unsafe {
                super::avx2::match_header_value_batch_32(bytes)
            };

            if let super::avx2::Scan::Found = scanned {
                return;
            }
        }
        if detect() == super::SSE_42 {
            unsafe {
                super::sse42::match_header_value_batch_16(bytes);
            }
        }

        // else do nothing
    }

    pub fn detect() -> usize {
        if cfg!(target_arch = "x86_64") && is_x86_feature_detected!("avx2") {
            super::AVX_2_AND_SSE_42
        } else if is_x86_feature_detected!("sse4.2") {
            super::SSE_42
        } else {
            super::NONE
        }
    }
}

#[cfg(all(
    httparse_simd,
    httparse_simd_target_feature_avx2,
    any(
        target_arch = "x86",
        target_arch = "x86_64",
    ),
))]
pub use self::avx2_compile_time::*;