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cmd/cgo, runtime: exported Go functions can't return a Go pointer

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Update #12416.

Change-Id: Iccbcb12709d1ca9bea87274f44f93cfcebadb070
Reviewed-on: https://go-review.googlesource.com/17048
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This commit is contained in:
Ian Lance Taylor 2015-11-18 21:25:44 -08:00
parent 0fbf0955d4
commit 0e2c635788
6 changed files with 135 additions and 63 deletions
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105
src/cmd/cgo/out.go
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@ -811,12 +811,13 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
}
fmt.Fprintf(fgcc, "}\n")
// Build the wrapper function compiled by gc.
goname := exp.Func.Name.Name
// Build the wrapper function compiled by cmd/compile.
goname := "_cgoexpwrap" + cPrefix + "_"
if fn.Recv != nil {
goname = "_cgoexpwrap" + cPrefix + "_" + fn.Recv.List[0].Names[0].Name + "_" + goname
goname += fn.Recv.List[0].Names[0].Name + "_"
}
fmt.Fprintf(fgo2, "//go:cgo_export_dynamic %s\n", goname)
goname += exp.Func.Name.Name
fmt.Fprintf(fgo2, "//go:cgo_export_dynamic %s\n", exp.Func.Name.Name)
fmt.Fprintf(fgo2, "//go:linkname _cgoexp%s_%s _cgoexp%s_%s\n", cPrefix, exp.ExpName, cPrefix, exp.ExpName)
fmt.Fprintf(fgo2, "//go:cgo_export_static _cgoexp%s_%s\n", cPrefix, exp.ExpName)
fmt.Fprintf(fgo2, "//go:nosplit\n") // no split stack, so no use of m or g
@ -829,44 +830,75 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
fmt.Fprintf(fm, "int _cgoexp%s_%s;\n", cPrefix, exp.ExpName)
// Calling a function with a receiver from C requires
// a Go wrapper function.
// This code uses printer.Fprint, not conf.Fprint,
// because we don't want //line comments in the middle
// of the function types.
fmt.Fprintf(fgo2, "\n")
fmt.Fprintf(fgo2, "func %s(", goname)
comma := false
if fn.Recv != nil {
fmt.Fprintf(fgo2, "func %s(recv ", goname)
conf.Fprint(fgo2, fset, fn.Recv.List[0].Type)
forFieldList(fntype.Params,
func(i int, aname string, atype ast.Expr) {
fmt.Fprintf(fgo2, ", p%d ", i)
conf.Fprint(fgo2, fset, atype)
})
fmt.Fprintf(fgo2, ")")
if gccResult != "void" {
fmt.Fprint(fgo2, " (")
forFieldList(fntype.Results,
func(i int, aname string, atype ast.Expr) {
if i > 0 {
fmt.Fprint(fgo2, ", ")
}
conf.Fprint(fgo2, fset, atype)
})
fmt.Fprint(fgo2, ")")
}
fmt.Fprint(fgo2, " {\n")
fmt.Fprint(fgo2, "\t")
if gccResult != "void" {
fmt.Fprint(fgo2, "return ")
}
fmt.Fprintf(fgo2, "recv.%s(", exp.Func.Name)
forFieldList(fntype.Params,
fmt.Fprintf(fgo2, "recv ")
printer.Fprint(fgo2, fset, fn.Recv.List[0].Type)
comma = true
}
forFieldList(fntype.Params,
func(i int, aname string, atype ast.Expr) {
if comma {
fmt.Fprintf(fgo2, ", ")
}
fmt.Fprintf(fgo2, "p%d ", i)
printer.Fprint(fgo2, fset, atype)
comma = true
})
fmt.Fprintf(fgo2, ")")
if gccResult != "void" {
fmt.Fprint(fgo2, " (")
forFieldList(fntype.Results,
func(i int, aname string, atype ast.Expr) {
if i > 0 {
fmt.Fprint(fgo2, ", ")
}
fmt.Fprintf(fgo2, "p%d", i)
fmt.Fprintf(fgo2, "r%d ", i)
printer.Fprint(fgo2, fset, atype)
})
fmt.Fprint(fgo2, ")\n")
fmt.Fprint(fgo2, "}\n")
fmt.Fprint(fgo2, ")")
}
fmt.Fprint(fgo2, " {\n")
if gccResult == "void" {
fmt.Fprint(fgo2, "\t")
} else {
// Verify that any results don't contain any
// Go pointers.
addedDefer := false
forFieldList(fntype.Results,
func(i int, aname string, atype ast.Expr) {
if !p.hasPointer(nil, atype, false) {
return
}
if !addedDefer {
fmt.Fprint(fgo2, "\tdefer func() {\n")
addedDefer = true
}
fmt.Fprintf(fgo2, "\t\t_cgoCheckResult(r%d)\n", i)
})
if addedDefer {
fmt.Fprint(fgo2, "\t}()\n")
}
fmt.Fprint(fgo2, "\treturn ")
}
if fn.Recv != nil {
fmt.Fprintf(fgo2, "recv.")
}
fmt.Fprintf(fgo2, "%s(", exp.Func.Name)
forFieldList(fntype.Params,
func(i int, aname string, atype ast.Expr) {
if i > 0 {
fmt.Fprint(fgo2, ", ")
}
fmt.Fprintf(fgo2, "p%d", i)
})
fmt.Fprint(fgo2, ")\n")
fmt.Fprint(fgo2, "}\n")
}
fmt.Fprintf(fgcch, "%s", gccExportHeaderEpilog)
@ -1251,6 +1283,9 @@ func _cgo_runtime_cgocallback(unsafe.Pointer, unsafe.Pointer, uintptr)
//go:linkname _cgoCheckPointer runtime.cgoCheckPointer
func _cgoCheckPointer(interface{}, ...interface{}) interface{}
//go:linkname _cgoCheckResult runtime.cgoCheckResult
func _cgoCheckResult(interface{})
`
const goStringDef = `