lex.go

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package noder
     6  
     7  import (
     8  	"fmt"
     9  	"internal/buildcfg"
    10  	"strings"
    11  
    12  	"cmd/compile/internal/ir"
    13  	"cmd/compile/internal/syntax"
    14  )
    15  
    16  func isSpace(c rune) bool {
    17  	return c == ' ' || c == '\t' || c == '\n' || c == '\r'
    18  }
    19  
    20  func isQuoted(s string) bool {
    21  	return len(s) >= 2 && s[0] == '"' && s[len(s)-1] == '"'
    22  }
    23  
    24  const (
    25  	funcPragmas = ir.Nointerface |
    26  		ir.Noescape |
    27  		ir.Norace |
    28  		ir.Nosplit |
    29  		ir.Noinline |
    30  		ir.NoCheckPtr |
    31  		ir.RegisterParams | // TODO(register args) remove after register abi is working
    32  		ir.CgoUnsafeArgs |
    33  		ir.UintptrKeepAlive |
    34  		ir.UintptrEscapes |
    35  		ir.Systemstack |
    36  		ir.Nowritebarrier |
    37  		ir.Nowritebarrierrec |
    38  		ir.Yeswritebarrierrec
    39  )
    40  
    41  func pragmaFlag(verb string) ir.PragmaFlag {
    42  	switch verb {
    43  	case "go:build":
    44  		return ir.GoBuildPragma
    45  	case "go:nointerface":
    46  		if buildcfg.Experiment.FieldTrack {
    47  			return ir.Nointerface
    48  		}
    49  	case "go:noescape":
    50  		return ir.Noescape
    51  	case "go:norace":
    52  		return ir.Norace
    53  	case "go:nosplit":
    54  		return ir.Nosplit | ir.NoCheckPtr // implies NoCheckPtr (see #34972)
    55  	case "go:noinline":
    56  		return ir.Noinline
    57  	case "go:nocheckptr":
    58  		return ir.NoCheckPtr
    59  	case "go:systemstack":
    60  		return ir.Systemstack
    61  	case "go:nowritebarrier":
    62  		return ir.Nowritebarrier
    63  	case "go:nowritebarrierrec":
    64  		return ir.Nowritebarrierrec | ir.Nowritebarrier // implies Nowritebarrier
    65  	case "go:yeswritebarrierrec":
    66  		return ir.Yeswritebarrierrec
    67  	case "go:cgo_unsafe_args":
    68  		return ir.CgoUnsafeArgs | ir.NoCheckPtr // implies NoCheckPtr (see #34968)
    69  	case "go:uintptrkeepalive":
    70  		return ir.UintptrKeepAlive
    71  	case "go:uintptrescapes":
    72  		// This directive extends //go:uintptrkeepalive by forcing
    73  		// uintptr arguments to escape to the heap, which makes stack
    74  		// growth safe.
    75  		return ir.UintptrEscapes | ir.UintptrKeepAlive // implies UintptrKeepAlive
    76  	case "go:registerparams": // TODO(register args) remove after register abi is working
    77  		return ir.RegisterParams
    78  	}
    79  	return 0
    80  }
    81  
    82  // pragcgo is called concurrently if files are parsed concurrently.
    83  func (p *noder) pragcgo(pos syntax.Pos, text string) {
    84  	f := pragmaFields(text)
    85  
    86  	verb := strings.TrimPrefix(f[0], "go:")
    87  	f[0] = verb
    88  
    89  	switch verb {
    90  	case "cgo_export_static", "cgo_export_dynamic":
    91  		switch {
    92  		case len(f) == 2 && !isQuoted(f[1]):
    93  		case len(f) == 3 && !isQuoted(f[1]) && !isQuoted(f[2]):
    94  		default:
    95  			p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf(`usage: //go:%s local [remote]`, verb)})
    96  			return
    97  		}
    98  	case "cgo_import_dynamic":
    99  		switch {
   100  		case len(f) == 2 && !isQuoted(f[1]):
   101  		case len(f) == 3 && !isQuoted(f[1]) && !isQuoted(f[2]):
   102  		case len(f) == 4 && !isQuoted(f[1]) && !isQuoted(f[2]) && isQuoted(f[3]):
   103  			f[3] = strings.Trim(f[3], `"`)
   104  			if buildcfg.GOOS == "aix" && f[3] != "" {
   105  				// On Aix, library pattern must be "lib.a/object.o"
   106  				// or "lib.a/libname.so.X"
   107  				n := strings.Split(f[3], "/")
   108  				if len(n) != 2 || !strings.HasSuffix(n[0], ".a") || (!strings.HasSuffix(n[1], ".o") && !strings.Contains(n[1], ".so.")) {
   109  					p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_import_dynamic local [remote ["lib.a/object.o"]]`})
   110  					return
   111  				}
   112  			}
   113  		default:
   114  			p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_import_dynamic local [remote ["library"]]`})
   115  			return
   116  		}
   117  	case "cgo_import_static":
   118  		switch {
   119  		case len(f) == 2 && !isQuoted(f[1]):
   120  		default:
   121  			p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_import_static local`})
   122  			return
   123  		}
   124  	case "cgo_dynamic_linker":
   125  		switch {
   126  		case len(f) == 2 && isQuoted(f[1]):
   127  			f[1] = strings.Trim(f[1], `"`)
   128  		default:
   129  			p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_dynamic_linker "path"`})
   130  			return
   131  		}
   132  	case "cgo_ldflag":
   133  		switch {
   134  		case len(f) == 2 && isQuoted(f[1]):
   135  			f[1] = strings.Trim(f[1], `"`)
   136  		default:
   137  			p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_ldflag "arg"`})
   138  			return
   139  		}
   140  	default:
   141  		return
   142  	}
   143  	p.pragcgobuf = append(p.pragcgobuf, f)
   144  }
   145  
   146  // pragmaFields is similar to strings.FieldsFunc(s, isSpace)
   147  // but does not split when inside double quoted regions and always
   148  // splits before the start and after the end of a double quoted region.
   149  // pragmaFields does not recognize escaped quotes. If a quote in s is not
   150  // closed the part after the opening quote will not be returned as a field.
   151  func pragmaFields(s string) []string {
   152  	var a []string
   153  	inQuote := false
   154  	fieldStart := -1 // Set to -1 when looking for start of field.
   155  	for i, c := range s {
   156  		switch {
   157  		case c == '"':
   158  			if inQuote {
   159  				inQuote = false
   160  				a = append(a, s[fieldStart:i+1])
   161  				fieldStart = -1
   162  			} else {
   163  				inQuote = true
   164  				if fieldStart >= 0 {
   165  					a = append(a, s[fieldStart:i])
   166  				}
   167  				fieldStart = i
   168  			}
   169  		case !inQuote && isSpace(c):
   170  			if fieldStart >= 0 {
   171  				a = append(a, s[fieldStart:i])
   172  				fieldStart = -1
   173  			}
   174  		default:
   175  			if fieldStart == -1 {
   176  				fieldStart = i
   177  			}
   178  		}
   179  	}
   180  	if !inQuote && fieldStart >= 0 { // Last field might end at the end of the string.
   181  		a = append(a, s[fieldStart:])
   182  	}
   183  	return a
   184  }
   185
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