[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/golang/snappy/encode_arm64.s b/vendor/github.com/golang/snappy/encode_arm64.s
new file mode 100644
index 0000000..bf83667
--- /dev/null
+++ b/vendor/github.com/golang/snappy/encode_arm64.s
@@ -0,0 +1,722 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !appengine
+// +build gc
+// +build !noasm
+
+#include "textflag.h"
+
+// The asm code generally follows the pure Go code in encode_other.go, except
+// where marked with a "!!!".
+
+// ----------------------------------------------------------------------------
+
+// func emitLiteral(dst, lit []byte) int
+//
+// All local variables fit into registers. The register allocation:
+// - R3 len(lit)
+// - R4 n
+// - R6 return value
+// - R8 &dst[i]
+// - R10 &lit[0]
+//
+// The 32 bytes of stack space is to call runtime·memmove.
+//
+// The unusual register allocation of local variables, such as R10 for the
+// source pointer, matches the allocation used at the call site in encodeBlock,
+// which makes it easier to manually inline this function.
+TEXT ·emitLiteral(SB), NOSPLIT, $32-56
+ MOVD dst_base+0(FP), R8
+ MOVD lit_base+24(FP), R10
+ MOVD lit_len+32(FP), R3
+ MOVD R3, R6
+ MOVW R3, R4
+ SUBW $1, R4, R4
+
+ CMPW $60, R4
+ BLT oneByte
+ CMPW $256, R4
+ BLT twoBytes
+
+threeBytes:
+ MOVD $0xf4, R2
+ MOVB R2, 0(R8)
+ MOVW R4, 1(R8)
+ ADD $3, R8, R8
+ ADD $3, R6, R6
+ B memmove
+
+twoBytes:
+ MOVD $0xf0, R2
+ MOVB R2, 0(R8)
+ MOVB R4, 1(R8)
+ ADD $2, R8, R8
+ ADD $2, R6, R6
+ B memmove
+
+oneByte:
+ LSLW $2, R4, R4
+ MOVB R4, 0(R8)
+ ADD $1, R8, R8
+ ADD $1, R6, R6
+
+memmove:
+ MOVD R6, ret+48(FP)
+
+ // copy(dst[i:], lit)
+ //
+ // This means calling runtime·memmove(&dst[i], &lit[0], len(lit)), so we push
+ // R8, R10 and R3 as arguments.
+ MOVD R8, 8(RSP)
+ MOVD R10, 16(RSP)
+ MOVD R3, 24(RSP)
+ CALL runtime·memmove(SB)
+ RET
+
+// ----------------------------------------------------------------------------
+
+// func emitCopy(dst []byte, offset, length int) int
+//
+// All local variables fit into registers. The register allocation:
+// - R3 length
+// - R7 &dst[0]
+// - R8 &dst[i]
+// - R11 offset
+//
+// The unusual register allocation of local variables, such as R11 for the
+// offset, matches the allocation used at the call site in encodeBlock, which
+// makes it easier to manually inline this function.
+TEXT ·emitCopy(SB), NOSPLIT, $0-48
+ MOVD dst_base+0(FP), R8
+ MOVD R8, R7
+ MOVD offset+24(FP), R11
+ MOVD length+32(FP), R3
+
+loop0:
+ // for length >= 68 { etc }
+ CMPW $68, R3
+ BLT step1
+
+ // Emit a length 64 copy, encoded as 3 bytes.
+ MOVD $0xfe, R2
+ MOVB R2, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+ SUB $64, R3, R3
+ B loop0
+
+step1:
+ // if length > 64 { etc }
+ CMP $64, R3
+ BLE step2
+
+ // Emit a length 60 copy, encoded as 3 bytes.
+ MOVD $0xee, R2
+ MOVB R2, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+ SUB $60, R3, R3
+
+step2:
+ // if length >= 12 || offset >= 2048 { goto step3 }
+ CMP $12, R3
+ BGE step3
+ CMPW $2048, R11
+ BGE step3
+
+ // Emit the remaining copy, encoded as 2 bytes.
+ MOVB R11, 1(R8)
+ LSRW $3, R11, R11
+ AND $0xe0, R11, R11
+ SUB $4, R3, R3
+ LSLW $2, R3
+ AND $0xff, R3, R3
+ ORRW R3, R11, R11
+ ORRW $1, R11, R11
+ MOVB R11, 0(R8)
+ ADD $2, R8, R8
+
+ // Return the number of bytes written.
+ SUB R7, R8, R8
+ MOVD R8, ret+40(FP)
+ RET
+
+step3:
+ // Emit the remaining copy, encoded as 3 bytes.
+ SUB $1, R3, R3
+ AND $0xff, R3, R3
+ LSLW $2, R3, R3
+ ORRW $2, R3, R3
+ MOVB R3, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+
+ // Return the number of bytes written.
+ SUB R7, R8, R8
+ MOVD R8, ret+40(FP)
+ RET
+
+// ----------------------------------------------------------------------------
+
+// func extendMatch(src []byte, i, j int) int
+//
+// All local variables fit into registers. The register allocation:
+// - R6 &src[0]
+// - R7 &src[j]
+// - R13 &src[len(src) - 8]
+// - R14 &src[len(src)]
+// - R15 &src[i]
+//
+// The unusual register allocation of local variables, such as R15 for a source
+// pointer, matches the allocation used at the call site in encodeBlock, which
+// makes it easier to manually inline this function.
+TEXT ·extendMatch(SB), NOSPLIT, $0-48
+ MOVD src_base+0(FP), R6
+ MOVD src_len+8(FP), R14
+ MOVD i+24(FP), R15
+ MOVD j+32(FP), R7
+ ADD R6, R14, R14
+ ADD R6, R15, R15
+ ADD R6, R7, R7
+ MOVD R14, R13
+ SUB $8, R13, R13
+
+cmp8:
+ // As long as we are 8 or more bytes before the end of src, we can load and
+ // compare 8 bytes at a time. If those 8 bytes are equal, repeat.
+ CMP R13, R7
+ BHI cmp1
+ MOVD (R15), R3
+ MOVD (R7), R4
+ CMP R4, R3
+ BNE bsf
+ ADD $8, R15, R15
+ ADD $8, R7, R7
+ B cmp8
+
+bsf:
+ // If those 8 bytes were not equal, XOR the two 8 byte values, and return
+ // the index of the first byte that differs.
+ // RBIT reverses the bit order, then CLZ counts the leading zeros, the
+ // combination of which finds the least significant bit which is set.
+ // The arm64 architecture is little-endian, and the shift by 3 converts
+ // a bit index to a byte index.
+ EOR R3, R4, R4
+ RBIT R4, R4
+ CLZ R4, R4
+ ADD R4>>3, R7, R7
+
+ // Convert from &src[ret] to ret.
+ SUB R6, R7, R7
+ MOVD R7, ret+40(FP)
+ RET
+
+cmp1:
+ // In src's tail, compare 1 byte at a time.
+ CMP R7, R14
+ BLS extendMatchEnd
+ MOVB (R15), R3
+ MOVB (R7), R4
+ CMP R4, R3
+ BNE extendMatchEnd
+ ADD $1, R15, R15
+ ADD $1, R7, R7
+ B cmp1
+
+extendMatchEnd:
+ // Convert from &src[ret] to ret.
+ SUB R6, R7, R7
+ MOVD R7, ret+40(FP)
+ RET
+
+// ----------------------------------------------------------------------------
+
+// func encodeBlock(dst, src []byte) (d int)
+//
+// All local variables fit into registers, other than "var table". The register
+// allocation:
+// - R3 . .
+// - R4 . .
+// - R5 64 shift
+// - R6 72 &src[0], tableSize
+// - R7 80 &src[s]
+// - R8 88 &dst[d]
+// - R9 96 sLimit
+// - R10 . &src[nextEmit]
+// - R11 104 prevHash, currHash, nextHash, offset
+// - R12 112 &src[base], skip
+// - R13 . &src[nextS], &src[len(src) - 8]
+// - R14 . len(src), bytesBetweenHashLookups, &src[len(src)], x
+// - R15 120 candidate
+// - R16 . hash constant, 0x1e35a7bd
+// - R17 . &table
+// - . 128 table
+//
+// The second column (64, 72, etc) is the stack offset to spill the registers
+// when calling other functions. We could pack this slightly tighter, but it's
+// simpler to have a dedicated spill map independent of the function called.
+//
+// "var table [maxTableSize]uint16" takes up 32768 bytes of stack space. An
+// extra 64 bytes, to call other functions, and an extra 64 bytes, to spill
+// local variables (registers) during calls gives 32768 + 64 + 64 = 32896.
+TEXT ·encodeBlock(SB), 0, $32896-56
+ MOVD dst_base+0(FP), R8
+ MOVD src_base+24(FP), R7
+ MOVD src_len+32(FP), R14
+
+ // shift, tableSize := uint32(32-8), 1<<8
+ MOVD $24, R5
+ MOVD $256, R6
+ MOVW $0xa7bd, R16
+ MOVKW $(0x1e35<<16), R16
+
+calcShift:
+ // for ; tableSize < maxTableSize && tableSize < len(src); tableSize *= 2 {
+ // shift--
+ // }
+ MOVD $16384, R2
+ CMP R2, R6
+ BGE varTable
+ CMP R14, R6
+ BGE varTable
+ SUB $1, R5, R5
+ LSL $1, R6, R6
+ B calcShift
+
+varTable:
+ // var table [maxTableSize]uint16
+ //
+ // In the asm code, unlike the Go code, we can zero-initialize only the
+ // first tableSize elements. Each uint16 element is 2 bytes and each
+ // iterations writes 64 bytes, so we can do only tableSize/32 writes
+ // instead of the 2048 writes that would zero-initialize all of table's
+ // 32768 bytes. This clear could overrun the first tableSize elements, but
+ // it won't overrun the allocated stack size.
+ ADD $128, RSP, R17
+ MOVD R17, R4
+
+ // !!! R6 = &src[tableSize]
+ ADD R6<<1, R17, R6
+
+memclr:
+ STP.P (ZR, ZR), 64(R4)
+ STP (ZR, ZR), -48(R4)
+ STP (ZR, ZR), -32(R4)
+ STP (ZR, ZR), -16(R4)
+ CMP R4, R6
+ BHI memclr
+
+ // !!! R6 = &src[0]
+ MOVD R7, R6
+
+ // sLimit := len(src) - inputMargin
+ MOVD R14, R9
+ SUB $15, R9, R9
+
+ // !!! Pre-emptively spill R5, R6 and R9 to the stack. Their values don't
+ // change for the rest of the function.
+ MOVD R5, 64(RSP)
+ MOVD R6, 72(RSP)
+ MOVD R9, 96(RSP)
+
+ // nextEmit := 0
+ MOVD R6, R10
+
+ // s := 1
+ ADD $1, R7, R7
+
+ // nextHash := hash(load32(src, s), shift)
+ MOVW 0(R7), R11
+ MULW R16, R11, R11
+ LSRW R5, R11, R11
+
+outer:
+ // for { etc }
+
+ // skip := 32
+ MOVD $32, R12
+
+ // nextS := s
+ MOVD R7, R13
+
+ // candidate := 0
+ MOVD $0, R15
+
+inner0:
+ // for { etc }
+
+ // s := nextS
+ MOVD R13, R7
+
+ // bytesBetweenHashLookups := skip >> 5
+ MOVD R12, R14
+ LSR $5, R14, R14
+
+ // nextS = s + bytesBetweenHashLookups
+ ADD R14, R13, R13
+
+ // skip += bytesBetweenHashLookups
+ ADD R14, R12, R12
+
+ // if nextS > sLimit { goto emitRemainder }
+ MOVD R13, R3
+ SUB R6, R3, R3
+ CMP R9, R3
+ BHI emitRemainder
+
+ // candidate = int(table[nextHash])
+ MOVHU 0(R17)(R11<<1), R15
+
+ // table[nextHash] = uint16(s)
+ MOVD R7, R3
+ SUB R6, R3, R3
+
+ MOVH R3, 0(R17)(R11<<1)
+
+ // nextHash = hash(load32(src, nextS), shift)
+ MOVW 0(R13), R11
+ MULW R16, R11
+ LSRW R5, R11, R11
+
+ // if load32(src, s) != load32(src, candidate) { continue } break
+ MOVW 0(R7), R3
+ MOVW (R6)(R15*1), R4
+ CMPW R4, R3
+ BNE inner0
+
+fourByteMatch:
+ // As per the encode_other.go code:
+ //
+ // A 4-byte match has been found. We'll later see etc.
+
+ // !!! Jump to a fast path for short (<= 16 byte) literals. See the comment
+ // on inputMargin in encode.go.
+ MOVD R7, R3
+ SUB R10, R3, R3
+ CMP $16, R3
+ BLE emitLiteralFastPath
+
+ // ----------------------------------------
+ // Begin inline of the emitLiteral call.
+ //
+ // d += emitLiteral(dst[d:], src[nextEmit:s])
+
+ MOVW R3, R4
+ SUBW $1, R4, R4
+
+ MOVW $60, R2
+ CMPW R2, R4
+ BLT inlineEmitLiteralOneByte
+ MOVW $256, R2
+ CMPW R2, R4
+ BLT inlineEmitLiteralTwoBytes
+
+inlineEmitLiteralThreeBytes:
+ MOVD $0xf4, R1
+ MOVB R1, 0(R8)
+ MOVW R4, 1(R8)
+ ADD $3, R8, R8
+ B inlineEmitLiteralMemmove
+
+inlineEmitLiteralTwoBytes:
+ MOVD $0xf0, R1
+ MOVB R1, 0(R8)
+ MOVB R4, 1(R8)
+ ADD $2, R8, R8
+ B inlineEmitLiteralMemmove
+
+inlineEmitLiteralOneByte:
+ LSLW $2, R4, R4
+ MOVB R4, 0(R8)
+ ADD $1, R8, R8
+
+inlineEmitLiteralMemmove:
+ // Spill local variables (registers) onto the stack; call; unspill.
+ //
+ // copy(dst[i:], lit)
+ //
+ // This means calling runtime·memmove(&dst[i], &lit[0], len(lit)), so we push
+ // R8, R10 and R3 as arguments.
+ MOVD R8, 8(RSP)
+ MOVD R10, 16(RSP)
+ MOVD R3, 24(RSP)
+
+ // Finish the "d +=" part of "d += emitLiteral(etc)".
+ ADD R3, R8, R8
+ MOVD R7, 80(RSP)
+ MOVD R8, 88(RSP)
+ MOVD R15, 120(RSP)
+ CALL runtime·memmove(SB)
+ MOVD 64(RSP), R5
+ MOVD 72(RSP), R6
+ MOVD 80(RSP), R7
+ MOVD 88(RSP), R8
+ MOVD 96(RSP), R9
+ MOVD 120(RSP), R15
+ ADD $128, RSP, R17
+ MOVW $0xa7bd, R16
+ MOVKW $(0x1e35<<16), R16
+ B inner1
+
+inlineEmitLiteralEnd:
+ // End inline of the emitLiteral call.
+ // ----------------------------------------
+
+emitLiteralFastPath:
+ // !!! Emit the 1-byte encoding "uint8(len(lit)-1)<<2".
+ MOVB R3, R4
+ SUBW $1, R4, R4
+ AND $0xff, R4, R4
+ LSLW $2, R4, R4
+ MOVB R4, (R8)
+ ADD $1, R8, R8
+
+ // !!! Implement the copy from lit to dst as a 16-byte load and store.
+ // (Encode's documentation says that dst and src must not overlap.)
+ //
+ // This always copies 16 bytes, instead of only len(lit) bytes, but that's
+ // OK. Subsequent iterations will fix up the overrun.
+ //
+ // Note that on arm64, it is legal and cheap to issue unaligned 8-byte or
+ // 16-byte loads and stores. This technique probably wouldn't be as
+ // effective on architectures that are fussier about alignment.
+ LDP 0(R10), (R0, R1)
+ STP (R0, R1), 0(R8)
+ ADD R3, R8, R8
+
+inner1:
+ // for { etc }
+
+ // base := s
+ MOVD R7, R12
+
+ // !!! offset := base - candidate
+ MOVD R12, R11
+ SUB R15, R11, R11
+ SUB R6, R11, R11
+
+ // ----------------------------------------
+ // Begin inline of the extendMatch call.
+ //
+ // s = extendMatch(src, candidate+4, s+4)
+
+ // !!! R14 = &src[len(src)]
+ MOVD src_len+32(FP), R14
+ ADD R6, R14, R14
+
+ // !!! R13 = &src[len(src) - 8]
+ MOVD R14, R13
+ SUB $8, R13, R13
+
+ // !!! R15 = &src[candidate + 4]
+ ADD $4, R15, R15
+ ADD R6, R15, R15
+
+ // !!! s += 4
+ ADD $4, R7, R7
+
+inlineExtendMatchCmp8:
+ // As long as we are 8 or more bytes before the end of src, we can load and
+ // compare 8 bytes at a time. If those 8 bytes are equal, repeat.
+ CMP R13, R7
+ BHI inlineExtendMatchCmp1
+ MOVD (R15), R3
+ MOVD (R7), R4
+ CMP R4, R3
+ BNE inlineExtendMatchBSF
+ ADD $8, R15, R15
+ ADD $8, R7, R7
+ B inlineExtendMatchCmp8
+
+inlineExtendMatchBSF:
+ // If those 8 bytes were not equal, XOR the two 8 byte values, and return
+ // the index of the first byte that differs.
+ // RBIT reverses the bit order, then CLZ counts the leading zeros, the
+ // combination of which finds the least significant bit which is set.
+ // The arm64 architecture is little-endian, and the shift by 3 converts
+ // a bit index to a byte index.
+ EOR R3, R4, R4
+ RBIT R4, R4
+ CLZ R4, R4
+ ADD R4>>3, R7, R7
+ B inlineExtendMatchEnd
+
+inlineExtendMatchCmp1:
+ // In src's tail, compare 1 byte at a time.
+ CMP R7, R14
+ BLS inlineExtendMatchEnd
+ MOVB (R15), R3
+ MOVB (R7), R4
+ CMP R4, R3
+ BNE inlineExtendMatchEnd
+ ADD $1, R15, R15
+ ADD $1, R7, R7
+ B inlineExtendMatchCmp1
+
+inlineExtendMatchEnd:
+ // End inline of the extendMatch call.
+ // ----------------------------------------
+
+ // ----------------------------------------
+ // Begin inline of the emitCopy call.
+ //
+ // d += emitCopy(dst[d:], base-candidate, s-base)
+
+ // !!! length := s - base
+ MOVD R7, R3
+ SUB R12, R3, R3
+
+inlineEmitCopyLoop0:
+ // for length >= 68 { etc }
+ MOVW $68, R2
+ CMPW R2, R3
+ BLT inlineEmitCopyStep1
+
+ // Emit a length 64 copy, encoded as 3 bytes.
+ MOVD $0xfe, R1
+ MOVB R1, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+ SUBW $64, R3, R3
+ B inlineEmitCopyLoop0
+
+inlineEmitCopyStep1:
+ // if length > 64 { etc }
+ MOVW $64, R2
+ CMPW R2, R3
+ BLE inlineEmitCopyStep2
+
+ // Emit a length 60 copy, encoded as 3 bytes.
+ MOVD $0xee, R1
+ MOVB R1, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+ SUBW $60, R3, R3
+
+inlineEmitCopyStep2:
+ // if length >= 12 || offset >= 2048 { goto inlineEmitCopyStep3 }
+ MOVW $12, R2
+ CMPW R2, R3
+ BGE inlineEmitCopyStep3
+ MOVW $2048, R2
+ CMPW R2, R11
+ BGE inlineEmitCopyStep3
+
+ // Emit the remaining copy, encoded as 2 bytes.
+ MOVB R11, 1(R8)
+ LSRW $8, R11, R11
+ LSLW $5, R11, R11
+ SUBW $4, R3, R3
+ AND $0xff, R3, R3
+ LSLW $2, R3, R3
+ ORRW R3, R11, R11
+ ORRW $1, R11, R11
+ MOVB R11, 0(R8)
+ ADD $2, R8, R8
+ B inlineEmitCopyEnd
+
+inlineEmitCopyStep3:
+ // Emit the remaining copy, encoded as 3 bytes.
+ SUBW $1, R3, R3
+ LSLW $2, R3, R3
+ ORRW $2, R3, R3
+ MOVB R3, 0(R8)
+ MOVW R11, 1(R8)
+ ADD $3, R8, R8
+
+inlineEmitCopyEnd:
+ // End inline of the emitCopy call.
+ // ----------------------------------------
+
+ // nextEmit = s
+ MOVD R7, R10
+
+ // if s >= sLimit { goto emitRemainder }
+ MOVD R7, R3
+ SUB R6, R3, R3
+ CMP R3, R9
+ BLS emitRemainder
+
+ // As per the encode_other.go code:
+ //
+ // We could immediately etc.
+
+ // x := load64(src, s-1)
+ MOVD -1(R7), R14
+
+ // prevHash := hash(uint32(x>>0), shift)
+ MOVW R14, R11
+ MULW R16, R11, R11
+ LSRW R5, R11, R11
+
+ // table[prevHash] = uint16(s-1)
+ MOVD R7, R3
+ SUB R6, R3, R3
+ SUB $1, R3, R3
+
+ MOVHU R3, 0(R17)(R11<<1)
+
+ // currHash := hash(uint32(x>>8), shift)
+ LSR $8, R14, R14
+ MOVW R14, R11
+ MULW R16, R11, R11
+ LSRW R5, R11, R11
+
+ // candidate = int(table[currHash])
+ MOVHU 0(R17)(R11<<1), R15
+
+ // table[currHash] = uint16(s)
+ ADD $1, R3, R3
+ MOVHU R3, 0(R17)(R11<<1)
+
+ // if uint32(x>>8) == load32(src, candidate) { continue }
+ MOVW (R6)(R15*1), R4
+ CMPW R4, R14
+ BEQ inner1
+
+ // nextHash = hash(uint32(x>>16), shift)
+ LSR $8, R14, R14
+ MOVW R14, R11
+ MULW R16, R11, R11
+ LSRW R5, R11, R11
+
+ // s++
+ ADD $1, R7, R7
+
+ // break out of the inner1 for loop, i.e. continue the outer loop.
+ B outer
+
+emitRemainder:
+ // if nextEmit < len(src) { etc }
+ MOVD src_len+32(FP), R3
+ ADD R6, R3, R3
+ CMP R3, R10
+ BEQ encodeBlockEnd
+
+ // d += emitLiteral(dst[d:], src[nextEmit:])
+ //
+ // Push args.
+ MOVD R8, 8(RSP)
+ MOVD $0, 16(RSP) // Unnecessary, as the callee ignores it, but conservative.
+ MOVD $0, 24(RSP) // Unnecessary, as the callee ignores it, but conservative.
+ MOVD R10, 32(RSP)
+ SUB R10, R3, R3
+ MOVD R3, 40(RSP)
+ MOVD R3, 48(RSP) // Unnecessary, as the callee ignores it, but conservative.
+
+ // Spill local variables (registers) onto the stack; call; unspill.
+ MOVD R8, 88(RSP)
+ CALL ·emitLiteral(SB)
+ MOVD 88(RSP), R8
+
+ // Finish the "d +=" part of "d += emitLiteral(etc)".
+ MOVD 56(RSP), R1
+ ADD R1, R8, R8
+
+encodeBlockEnd:
+ MOVD dst_base+0(FP), R3
+ SUB R3, R8, R8
+ MOVD R8, d+48(FP)
+ RET