where is the implementation of `getg`?

[Jiajun Huang]

Hi, all:

     I'm reading golang runtime implementation, I've got a function definition:

// getg returns the pointer to the current g.
// The compiler rewrites calls to this function into instructions
// that fetch the g directly (from TLS or from the dedicated register).
func getg() *g

    So, is there any solution that I can reading what implementation does the compiler rewrite? It seems that it's Assembly code.

[Dave Cheney]

A long time ago getg was written in assembly in the runtime package. These days it is implemented directly as pseudo instruction in the compiler. Search for OpGetG in $GOROOT/src/cmd/compile/internal

[Ian Lance Taylor]

On Tue, Jan 16, 2018 at 5:51 PM, Dave Cheney <da...@cheney.net> wrote:
> A long time ago getg was written in assembly in the runtime package. These
> days it is implemented directly as pseudo instruction in the compiler.
> Search for OpGetG in $GOROOT/src/cmd/compile/internal

Yes. The simplest way to see the generated instructions is to
disassemble the runtime package and look for a place that you know is
a call to getg.

Ian

> On Wednesday, 17 January 2018 12:40:48 UTC+11, Jiajun Huang wrote:
>>
>> Hi, all:
>>
>> I'm reading golang runtime implementation, I've got a function
>> definition:
>>
>> // getg returns the pointer to the current g.
>> // The compiler rewrites calls to this function into instructions
>> // that fetch the g directly (from TLS or from the dedicated register).
>> func getg() *g
>>
>>
>> So, is there any solution that I can reading what implementation does
>> the compiler rewrite? It seems that it's Assembly code.
>

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[gansteed]

thanks

Ian Lance Taylor <ia...@golang.org>于2018年1月17日周三 上午9:53写道：

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