diff options
Diffstat (limited to 'compiler/rustc_span/src/analyze_source_file.rs')
| -rw-r--r-- | compiler/rustc_span/src/analyze_source_file.rs | 268 |
1 files changed, 31 insertions, 237 deletions
diff --git a/compiler/rustc_span/src/analyze_source_file.rs b/compiler/rustc_span/src/analyze_source_file.rs index fba20566580..141d261b5f0 100644 --- a/compiler/rustc_span/src/analyze_source_file.rs +++ b/compiler/rustc_span/src/analyze_source_file.rs @@ -29,165 +29,6 @@ pub(crate) fn analyze_source_file(src: &str) -> (Vec<RelativeBytePos>, Vec<Multi (lines, multi_byte_chars) } -#[cfg(bootstrap)] -cfg_match! { - cfg(any(target_arch = "x86", target_arch = "x86_64")) => { - fn analyze_source_file_dispatch( - src: &str, - lines: &mut Vec<RelativeBytePos>, - multi_byte_chars: &mut Vec<MultiByteChar>, - ) { - if is_x86_feature_detected!("sse2") { - unsafe { - analyze_source_file_sse2(src, lines, multi_byte_chars); - } - } else { - analyze_source_file_generic( - src, - src.len(), - RelativeBytePos::from_u32(0), - lines, - multi_byte_chars, - ); - } - } - - /// Checks 16 byte chunks of text at a time. If the chunk contains - /// something other than printable ASCII characters and newlines, the - /// function falls back to the generic implementation. Otherwise it uses - /// SSE2 intrinsics to quickly find all newlines. - #[target_feature(enable = "sse2")] - unsafe fn analyze_source_file_sse2( - src: &str, - lines: &mut Vec<RelativeBytePos>, - multi_byte_chars: &mut Vec<MultiByteChar>, - ) { - #[cfg(target_arch = "x86")] - use std::arch::x86::*; - #[cfg(target_arch = "x86_64")] - use std::arch::x86_64::*; - - const CHUNK_SIZE: usize = 16; - - let src_bytes = src.as_bytes(); - - let chunk_count = src.len() / CHUNK_SIZE; - - // This variable keeps track of where we should start decoding a - // chunk. If a multi-byte character spans across chunk boundaries, - // we need to skip that part in the next chunk because we already - // handled it. - let mut intra_chunk_offset = 0; - - for chunk_index in 0..chunk_count { - let ptr = src_bytes.as_ptr() as *const __m128i; - // We don't know if the pointer is aligned to 16 bytes, so we - // use `loadu`, which supports unaligned loading. - let chunk = unsafe { _mm_loadu_si128(ptr.add(chunk_index)) }; - - // For character in the chunk, see if its byte value is < 0, which - // indicates that it's part of a UTF-8 char. - let multibyte_test = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(0)) }; - // Create a bit mask from the comparison results. - let multibyte_mask = unsafe { _mm_movemask_epi8(multibyte_test) }; - - // If the bit mask is all zero, we only have ASCII chars here: - if multibyte_mask == 0 { - assert!(intra_chunk_offset == 0); - - // Check if there are any control characters in the chunk. All - // control characters that we can encounter at this point have a - // byte value less than 32 or ... - let control_char_test0 = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(32)) }; - let control_char_mask0 = unsafe { _mm_movemask_epi8(control_char_test0) }; - - // ... it's the ASCII 'DEL' character with a value of 127. - let control_char_test1 = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(127)) }; - let control_char_mask1 = unsafe { _mm_movemask_epi8(control_char_test1) }; - - let control_char_mask = control_char_mask0 | control_char_mask1; - - if control_char_mask != 0 { - // Check for newlines in the chunk - let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) }; - let newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) }; - - if control_char_mask == newlines_mask { - // All control characters are newlines, record them - let mut newlines_mask = 0xFFFF0000 | newlines_mask as u32; - let output_offset = RelativeBytePos::from_usize(chunk_index * CHUNK_SIZE + 1); - - loop { - let index = newlines_mask.trailing_zeros(); - - if index >= CHUNK_SIZE as u32 { - // We have arrived at the end of the chunk. - break; - } - - lines.push(RelativeBytePos(index) + output_offset); - - // Clear the bit, so we can find the next one. - newlines_mask &= (!1) << index; - } - - // We are done for this chunk. All control characters were - // newlines and we took care of those. - continue; - } else { - // Some of the control characters are not newlines, - // fall through to the slow path below. - } - } else { - // No control characters, nothing to record for this chunk - continue; - } - } - - // The slow path. - // There are control chars in here, fallback to generic decoding. - let scan_start = chunk_index * CHUNK_SIZE + intra_chunk_offset; - intra_chunk_offset = analyze_source_file_generic( - &src[scan_start..], - CHUNK_SIZE - intra_chunk_offset, - RelativeBytePos::from_usize(scan_start), - lines, - multi_byte_chars, - ); - } - - // There might still be a tail left to analyze - let tail_start = chunk_count * CHUNK_SIZE + intra_chunk_offset; - if tail_start < src.len() { - analyze_source_file_generic( - &src[tail_start..], - src.len() - tail_start, - RelativeBytePos::from_usize(tail_start), - lines, - multi_byte_chars, - ); - } - } - } - _ => { - // The target (or compiler version) does not support SSE2 ... - fn analyze_source_file_dispatch( - src: &str, - lines: &mut Vec<RelativeBytePos>, - multi_byte_chars: &mut Vec<MultiByteChar>, - ) { - analyze_source_file_generic( - src, - src.len(), - RelativeBytePos::from_u32(0), - lines, - multi_byte_chars, - ); - } - } -} - -#[cfg(not(bootstrap))] cfg_match! { any(target_arch = "x86", target_arch = "x86_64") => { fn analyze_source_file_dispatch( @@ -227,9 +68,7 @@ cfg_match! { const CHUNK_SIZE: usize = 16; - let src_bytes = src.as_bytes(); - - let chunk_count = src.len() / CHUNK_SIZE; + let (chunks, tail) = src.as_bytes().as_chunks::<CHUNK_SIZE>(); // This variable keeps track of where we should start decoding a // chunk. If a multi-byte character spans across chunk boundaries, @@ -237,11 +76,10 @@ cfg_match! { // handled it. let mut intra_chunk_offset = 0; - for chunk_index in 0..chunk_count { - let ptr = src_bytes.as_ptr() as *const __m128i; + for (chunk_index, chunk) in chunks.iter().enumerate() { // We don't know if the pointer is aligned to 16 bytes, so we // use `loadu`, which supports unaligned loading. - let chunk = unsafe { _mm_loadu_si128(ptr.add(chunk_index)) }; + let chunk = unsafe { _mm_loadu_si128(chunk.as_ptr() as *const __m128i) }; // For character in the chunk, see if its byte value is < 0, which // indicates that it's part of a UTF-8 char. @@ -253,69 +91,36 @@ cfg_match! { if multibyte_mask == 0 { assert!(intra_chunk_offset == 0); - // Check if there are any control characters in the chunk. All - // control characters that we can encounter at this point have a - // byte value less than 32 or ... - let control_char_test0 = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(32)) }; - let control_char_mask0 = unsafe { _mm_movemask_epi8(control_char_test0) }; - - // ... it's the ASCII 'DEL' character with a value of 127. - let control_char_test1 = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(127)) }; - let control_char_mask1 = unsafe { _mm_movemask_epi8(control_char_test1) }; - - let control_char_mask = control_char_mask0 | control_char_mask1; - - if control_char_mask != 0 { - // Check for newlines in the chunk - let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) }; - let newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) }; + // Check for newlines in the chunk + let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) }; + let mut newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) }; - if control_char_mask == newlines_mask { - // All control characters are newlines, record them - let mut newlines_mask = 0xFFFF0000 | newlines_mask as u32; - let output_offset = RelativeBytePos::from_usize(chunk_index * CHUNK_SIZE + 1); + let output_offset = RelativeBytePos::from_usize(chunk_index * CHUNK_SIZE + 1); - loop { - let index = newlines_mask.trailing_zeros(); + while newlines_mask != 0 { + let index = newlines_mask.trailing_zeros(); - if index >= CHUNK_SIZE as u32 { - // We have arrived at the end of the chunk. - break; - } + lines.push(RelativeBytePos(index) + output_offset); - lines.push(RelativeBytePos(index) + output_offset); - - // Clear the bit, so we can find the next one. - newlines_mask &= (!1) << index; - } - - // We are done for this chunk. All control characters were - // newlines and we took care of those. - continue; - } else { - // Some of the control characters are not newlines, - // fall through to the slow path below. - } - } else { - // No control characters, nothing to record for this chunk - continue; + // Clear the bit, so we can find the next one. + newlines_mask &= newlines_mask - 1; } + } else { + // The slow path. + // There are multibyte chars in here, fallback to generic decoding. + let scan_start = chunk_index * CHUNK_SIZE + intra_chunk_offset; + intra_chunk_offset = analyze_source_file_generic( + &src[scan_start..], + CHUNK_SIZE - intra_chunk_offset, + RelativeBytePos::from_usize(scan_start), + lines, + multi_byte_chars, + ); } - - // The slow path. - // There are control chars in here, fallback to generic decoding. - let scan_start = chunk_index * CHUNK_SIZE + intra_chunk_offset; - intra_chunk_offset = analyze_source_file_generic( - &src[scan_start..], - CHUNK_SIZE - intra_chunk_offset, - RelativeBytePos::from_usize(scan_start), - lines, - multi_byte_chars, - ); } // There might still be a tail left to analyze - let tail_start = chunk_count * CHUNK_SIZE + intra_chunk_offset; + let tail_start = src.len() - tail.len() + intra_chunk_offset; if tail_start < src.len() { analyze_source_file_generic( &src[tail_start..], @@ -369,29 +174,18 @@ fn analyze_source_file_generic( // string. let mut char_len = 1; - if byte < 32 { - // This is an ASCII control character, it could be one of the cases - // that are interesting to us. - + if byte == b'\n' { let pos = RelativeBytePos::from_usize(i) + output_offset; - - if let b'\n' = byte { - lines.push(pos + RelativeBytePos(1)); - } - } else if byte >= 127 { - // The slow path: - // This is either ASCII control character "DEL" or the beginning of - // a multibyte char. Just decode to `char`. + lines.push(pos + RelativeBytePos(1)); + } else if byte >= 128 { + // This is the beginning of a multibyte char. Just decode to `char`. let c = src[i..].chars().next().unwrap(); char_len = c.len_utf8(); let pos = RelativeBytePos::from_usize(i) + output_offset; - - if char_len > 1 { - assert!((2..=4).contains(&char_len)); - let mbc = MultiByteChar { pos, bytes: char_len as u8 }; - multi_byte_chars.push(mbc); - } + assert!((2..=4).contains(&char_len)); + let mbc = MultiByteChar { pos, bytes: char_len as u8 }; + multi_byte_chars.push(mbc); } i += char_len; |