Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

[dev.cc] cmd/asm: the text flag argument to TEXT psudo-op is optional

Browse source 
Allow TEXT to have two or three operands.
In
	TEXT foo(SB),flag,$0
the flag can be missing, in which case we take it to be zero.

Change-Id: I7b88543b52019f7890baac4b95f9e63884d43c83
Reviewed-on: https://go-review.googlesource.com/3440
Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Rob Pike 2015-01-28 10:21:04 -08:00
parent 92e5120c77
commit ad82238653
1 changed files with 14 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

20
src/cmd/asm/internal/asm/asm.go
View file

@ -146,8 +146,8 @@ func (p *Parser) append(prog *obj.Prog, doLabel bool) {
// asmText assembles a TEXT pseudo-op. // asmText assembles a TEXT pseudo-op.
// TEXT runtime·sigtramp(SB),4,$0-0 // TEXT runtime·sigtramp(SB),4,$0-0
func (p *Parser) asmText(word string, operands [][]lex.Token) { func (p *Parser) asmText(word string, operands [][]lex.Token) {
if len(operands) != 3 { if len(operands) != 2 && len(operands) != 3 {
p.errorf("expect three operands for TEXT") p.errorf("expect two or three operands for TEXT")
} }
// Operand 0 is the symbol name in the form foo(SB). // Operand 0 is the symbol name in the form foo(SB).
@ -157,22 +157,26 @@ func (p *Parser) asmText(word string, operands [][]lex.Token) {
p.errorf("TEXT symbol %q must be an offset from SB", nameAddr.Symbol) p.errorf("TEXT symbol %q must be an offset from SB", nameAddr.Symbol)
} }
name := nameAddr.Symbol name := nameAddr.Symbol
next := 1
// Operand 1 is the text flag, a literal integer. // Next operand is the optional text flag, a literal integer.
// TODO: This is optional but this parser takes it as required. flag := int8(0)
flagAddr := p.address(operands[1]) if len(operands) == 3 {
flagAddr := p.address(operands[next])
if !flagAddr.Is(addr.Offset) { if !flagAddr.Is(addr.Offset) {
p.errorf("TEXT flag for %s must be an integer", name) p.errorf("TEXT flag for %s must be an integer", name)
} }
flag := int8(flagAddr.Offset) flag = int8(flagAddr.Offset)
next++
}
// Operand 2 is the frame and arg size. // Next operand is the frame and arg size.
// Bizarre syntax: $frameSize-argSize is two words, not subtraction. // Bizarre syntax: $frameSize-argSize is two words, not subtraction.
// Both frameSize and argSize must be simple integers; only frameSize // Both frameSize and argSize must be simple integers; only frameSize
// can be negative. // can be negative.
// The "-argSize" may be missing; if so, set it to obj.ArgsSizeUnknown. // The "-argSize" may be missing; if so, set it to obj.ArgsSizeUnknown.
// Parse left to right. // Parse left to right.
op := operands[2] op := operands[next]
if len(op) < 2 || op[0].ScanToken != '$' { if len(op) < 2 || op[0].ScanToken != '$' {
p.errorf("TEXT %s: frame size must be an immediate constant", name) p.errorf("TEXT %s: frame size must be an immediate constant", name)
} }