# Copyright (c) 2017, Google Inc.
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

# This is a rough parser for x86-64 and ppc64le assembly designed to work with
# https://github.com/pointlander/peg. delocate.go has a go:generate line for
# rebuilding delocate.peg.go from this file.

package main

type Asm Peg {}

AsmFile <- Statement* !.
Statement <- WS? (Label / ((GlobalDirective /
                            LocationDirective /
                            LabelContainingDirective /
                            Instruction /
                            Directive /
                            Comment / ) WS? ((Comment? '\n') / ';')))
GlobalDirective <- (".global" / ".globl") WS SymbolName
Directive <- '.' DirectiveName (WS Args)?
DirectiveName <- [[A-Z0-9_]]+
LocationDirective <- (".file" / ".loc") WS [^#\n]+
Args <- Arg ((WS? ',' WS?) Arg)*
Arg <- QuotedArg / [[0-9a-z%+\-_@.]]*
QuotedArg <- '"' QuotedText '"'
QuotedText <- (EscapedChar / [^"])*
LabelContainingDirective <- LabelContainingDirectiveName WS SymbolArgs
LabelContainingDirectiveName <- ".long" / ".set" / ".8byte" / ".4byte" / ".quad" / ".tc" / ".localentry" / ".size" / ".type"
SymbolArgs <- SymbolArg ((WS? ',' WS?) SymbolArg)*
SymbolArg <- Offset /
             SymbolType /
             (Offset / LocalSymbol / SymbolName / Dot) WS? Operator WS? (Offset / LocalSymbol / SymbolName) /
             LocalSymbol TCMarker? /
             SymbolName Offset /
             SymbolName TCMarker?
SymbolType <- '@function' / '@object'
Dot <- '.'
TCMarker <- '[TC]'
EscapedChar <- '\\' .
WS <- [ \t]+
Comment <- '#' [^\n]*
Label <- (LocalSymbol / LocalLabel / SymbolName) ':'
SymbolName <- [[A-Z._]][[A-Z.0-9$_]]*
LocalSymbol <- '.L' [[A-Z.0-9$_]]+
LocalLabel <- [0-9][0-9$]*
LocalLabelRef <- [0-9][0-9$]*[bf]
Instruction <- InstructionName (WS InstructionArg ((WS? ',' WS?) InstructionArg)*)?
InstructionName <- [[A-Z]][[A-Z0-9]]* [.+\-]?
InstructionArg <- IndirectionIndicator? (RegisterOrConstant / LocalLabelRef / TOCRefHigh / TOCRefLow / MemoryRef)
TOCRefHigh <- '.TOC.-' ('0b' / ('.L' [a-zA-Z_0-9]+)) "@ha"
TOCRefLow <- '.TOC.-' ('0b' / ('.L' [a-zA-Z_0-9]+)) "@l"
IndirectionIndicator <- '*'
RegisterOrConstant <- (('%'[[A-Z]][[A-Z0-9]]*) / ('$'? ((Offset Offset) / Offset))) ![fb:(+\-]
# Compilers only output a very limited number of expression forms. Rather than
# implement a full expression parser, this enumerate those forms plus a few
# that appear in our hand-written assembly.
MemoryRef <- (SymbolRef BaseIndexScale /
              SymbolRef /
              Offset* BaseIndexScale /
              SegmentRegister Offset BaseIndexScale /
              SegmentRegister BaseIndexScale /
              SegmentRegister Offset /
              BaseIndexScale)
SymbolRef <- (Offset* '+')? (LocalSymbol / SymbolName) Offset* ('@' Section Offset*)?
BaseIndexScale <- '(' RegisterOrConstant? WS? (',' WS? RegisterOrConstant WS? (',' [0-9]+)? )? ')'
Operator <- [+\-]
Offset <- '+'? '-'? (("0b" [01]+) / ("0x" [[0-9A-F]]+) / [0-9]+)
Section <- [[A-Z@]]+
SegmentRegister <- '%' [c-gs] 's:'