• Russ Cox's avatar
    cmd/cgo: modify source as text, not as AST · 85c3ebf4
    Russ Cox authored
    Cgo has always operated by rewriting the AST and invoking go/printer.
    This CL converts it to use the AST to make decisions but then apply
    its edits directly to the underlying source text. This approach worked
    better in rsc.io/grind (used during the C to Go conversion) and also
    more recently in cmd/cover. It guarantees that all comments and
    line numbers are preserved exactly.
    
    This eliminates a lot of special concern about comments and
    problems with cgo not preserving meaningful comments.
    Combined with the CL changing cmd/cover to use the same
    approach, it means that the combination of applying cgo and
    applying cover still guarantees all comments and line numbers
    are preserved exactly.
    
    This sets us up to fix some cgo vs cover bugs by swapping
    the order in which they run during the go command.
    
    This also sets up #16623 a bit: the edit list being
    accumulated here is nearly exactly what you'd want
    to pass to the compiler for that issue.
    
    Change-Id: I7611815be22e7c5c0d4fc3fa11832c42b32c4eb3
    Reviewed-on: https://go-review.googlesource.com/77153Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
    85c3ebf4
buildtool.go 9.02 KB