Jump table

[Pierre Durand]

Hello,

Does the Go compiler generate jump table ?

If I write a switch case (with fixed string or int value), and return immediately, does it generate a jump table ?

If so, can you show me the file where it is done.

Thank you :)

[Jan Mercl]

eg. https://github.com/golang/go/blob/cead111a772c2852c870fb140029d89152da4d14/src/cmd/compile/internal/walk/switch.go#L297

[Pierre Durand]

Thank you :)

[Brian Candler]

Aside: Godbolt is a useful tool if you want to see what assembly is generated for some given source code.

Try:

https://godbolt.org/z/K6M6evxE6

[Pierre Durand]

Yes I'm also using gobolt, but my switch/case was too small.

Thank you :) 

[Jon Perryman]

As an FYI, don't forget to specify -O3 otherwise you may see less than optimal asm code generated. Also note that hovering over the assembler instruction will display help text describing the instruction (useful for understanding instructions). You can easily switch between machine architectures to see it's effect.