cgo: define CGO_CFLAGS and CGO_LDFLAGS in Go files
R=rsc, binet
CC=golang-dev
https://golang.org/cl/3921043
diff --git a/src/Make.pkg b/src/Make.pkg
index ec7d572..0ffab72 100644
--- a/src/Make.pkg
+++ b/src/Make.pkg
@@ -48,7 +48,7 @@
6cov -g $(shell pwd) $O.out | grep -v '_test\.go:'
CLEANFILES+=*.cgo1.go *.cgo2.c _cgo_defun.c _cgo_gotypes.go _cgo_export.*
-CLEANFILES+=_cgo_.c _cgo_import.c _cgo_main.c
+CLEANFILES+=_cgo_.c _cgo_import.c _cgo_main.c _cgo_flags _cgo_run
CLEANFILES+=*.so _obj _test _testmain.go *.exe
test:
@@ -112,11 +112,21 @@
#
ifdef CGOFILES
-_cgo_defun.c: $(CGOFILES)
+_cgo_run: $(CGOFILES)
+ @touch _cgo_run
CGOPKGPATH=$(dir) cgo -- $(CGO_CFLAGS) $(CGOFILES)
+# _CGO_CFLAGS and _CGO_LDFLAGS are defined via the evaluation of _cgo_flags.
+# The include happens before the commands in the recipe run,
+# so it cannot be done in the same recipe that runs cgo.
+_cgo_flags: _cgo_run
+ $(eval include _cgo_flags)
+
+# Include any previous flags in case cgo files are up to date.
+-include _cgo_flags
+
# Ugly but necessary - cgo writes these files too.
-_cgo_gotypes.go _cgo_export.c _cgo_export.h _cgo_main.c: _cgo_defun.c
+_cgo_gotypes.go _cgo_export.c _cgo_export.h _cgo_main.c _cgo_defun.c: _cgo_flags
@true
%.cgo1.go %.cgo2.c: _cgo_defun.c
@@ -125,7 +135,7 @@
# Compile rules for gcc source files.
%.o: %.c
- $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $*.c
+ $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $(_CGO_CFLAGS) $*.c
# To find out which symbols are needed from external libraries
# and which libraries are needed, we build a simple a.out that
@@ -136,10 +146,10 @@
# by Go code. That's crosscall2 and any exported symbols.
_cgo_main.o: _cgo_main.c
- $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) _cgo_main.c
+ $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $(_CGO_CFLAGS) _cgo_main.c
_cgo1_.o: _cgo_main.o $(CGO_OFILES)
- $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ $^ $(CGO_LDFLAGS)
+ $(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ $^ $(CGO_LDFLAGS) $(_CGO_LDFLAGS)
_cgo_import.c: _cgo1_.o
cgo -dynimport _cgo1_.o >_$@ && mv -f _$@ $@
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go
index 0f9204d..c486834 100644
--- a/src/cmd/cgo/doc.go
+++ b/src/cmd/cgo/doc.go
@@ -23,6 +23,15 @@
// #include <errno.h>
import "C"
+CFLAGS and LDFLAGS may be defined with pseudo #cgo directives
+within these comments to tweak the behavior of gcc. Values defined
+in multiple directives are concatenated together. For example:
+
+ // #cgo CFLAGS: -DPNG_DEBUG=1
+ // #cgo LDFLAGS: -lpng
+ // #include <png.h>
+ import "C"
+
C identifiers or field names that are keywords in Go can be
accessed by prefixing them with an underscore: if x points at
a C struct with a field named "type", x._type accesses the field.
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index e400fcd..cadc6fa 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -21,6 +21,7 @@
"os"
"strconv"
"strings"
+ "unicode"
)
var debugDefine = flag.Bool("debug-define", false, "print relevant #defines")
@@ -59,6 +60,107 @@
return s
}
+// ParseFlags extracts #cgo CFLAGS and LDFLAGS options from the file
+// preamble. Multiple occurrences are concatenated with a separating space,
+// even across files.
+func (p *Package) ParseFlags(f *File, srcfile string) {
+ linesIn := strings.Split(f.Preamble, "\n", -1)
+ linesOut := make([]string, 0, len(linesIn))
+ for _, line := range linesIn {
+ l := strings.TrimSpace(line)
+ if len(l) < 5 || l[:4] != "#cgo" || !unicode.IsSpace(int(l[4])) {
+ linesOut = append(linesOut, line)
+ continue
+ }
+
+ l = strings.TrimSpace(l[4:])
+ fields := strings.Split(l, ":", 2)
+ if len(fields) != 2 {
+ fatal("%s: bad #cgo line: %s", srcfile, line)
+ }
+
+ k := fields[0]
+ v := strings.TrimSpace(fields[1])
+ if k != "CFLAGS" && k != "LDFLAGS" {
+ fatal("%s: unsupported #cgo option %s", srcfile, k)
+ }
+ args, err := splitQuoted(v)
+ if err != nil {
+ fatal("%s: bad #cgo option %s: %s", srcfile, k, err.String())
+ }
+ if oldv, ok := p.CgoFlags[k]; ok {
+ p.CgoFlags[k] = oldv + " " + v
+ } else {
+ p.CgoFlags[k] = v
+ }
+ if k == "CFLAGS" {
+ p.GccOptions = append(p.GccOptions, args...)
+ }
+ }
+ f.Preamble = strings.Join(linesOut, "\n")
+}
+
+// splitQuoted splits the string s around each instance of one or more consecutive
+// white space characters while taking into account quotes and escaping, and
+// returns an array of substrings of s or an empty list if s contains only white space.
+// Single quotes and double quotes are recognized to prevent splitting within the
+// quoted region, and are removed from the resulting substrings. If a quote in s
+// isn't closed err will be set and r will have the unclosed argument as the
+// last element. The backslash is used for escaping.
+//
+// For example, the following string:
+//
+// `a b:"c d" 'e''f' "g\""`
+//
+// Would be parsed as:
+//
+// []string{"a", "b:c d", "ef", `g"`}
+//
+func splitQuoted(s string) (r []string, err os.Error) {
+ var args []string
+ arg := make([]int, len(s))
+ escaped := false
+ quoted := false
+ quote := 0
+ i := 0
+ for _, rune := range s {
+ switch {
+ case escaped:
+ escaped = false
+ case rune == '\\':
+ escaped = true
+ continue
+ case quote != 0:
+ if rune == quote {
+ quote = 0
+ continue
+ }
+ case rune == '"' || rune == '\'':
+ quoted = true
+ quote = rune
+ continue
+ case unicode.IsSpace(rune):
+ if quoted || i > 0 {
+ quoted = false
+ args = append(args, string(arg[:i]))
+ i = 0
+ }
+ continue
+ }
+ arg[i] = rune
+ i++
+ }
+ if quoted || i > 0 {
+ args = append(args, string(arg[:i]))
+ }
+ if quote != 0 {
+ err = os.ErrorString("unclosed quote")
+ } else if escaped {
+ err = os.ErrorString("unfinished escaping")
+ }
+ return args, err
+}
+
// Translate rewrites f.AST, the original Go input, to remove
// references to the imported package C, replacing them with
// references to the equivalent Go types, functions, and variables.
diff --git a/src/cmd/cgo/main.go b/src/cmd/cgo/main.go
index 5d2bfd0..b15d345 100644
--- a/src/cmd/cgo/main.go
+++ b/src/cmd/cgo/main.go
@@ -29,6 +29,7 @@
PackagePath string
PtrSize int64
GccOptions []string
+ CgoFlags map[string]string // #cgo flags (CFLAGS, LDFLAGS)
Written map[string]bool
Name map[string]*Name // accumulated Name from Files
Typedef map[string]ast.Expr // accumulated Typedef from Files
@@ -161,7 +162,12 @@
if i == len(args) {
usage()
}
- gccOptions, goFiles := args[0:i], args[i:]
+
+ // Copy it to a new slice so it can grow.
+ gccOptions := make([]string, i)
+ copy(gccOptions, args[0:i])
+
+ goFiles := args[i:]
arch := os.Getenv("GOARCH")
if arch == "" {
@@ -180,6 +186,7 @@
p := &Package{
PtrSize: ptrSize,
GccOptions: gccOptions,
+ CgoFlags: make(map[string]string),
Written: make(map[string]bool),
}
@@ -199,11 +206,17 @@
}
cPrefix = fmt.Sprintf("_%x", h.Sum()[0:6])
- for _, input := range goFiles {
+ fs := make([]*File, len(goFiles))
+ for i, input := range goFiles {
+ // Parse flags for all files before translating due to CFLAGS.
f := new(File)
- // Reset f.Preamble so that we don't end up with conflicting headers / defines
- f.Preamble = ""
f.ReadGo(input)
+ p.ParseFlags(f, input)
+ fs[i] = f
+ }
+
+ for i, input := range goFiles {
+ f := fs[i]
p.Translate(f)
for _, cref := range f.Ref {
switch cref.Context {
diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index d5fc634..ede8f57 100644
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -33,6 +33,12 @@
fc := creat("_cgo_defun.c")
fm := creat("_cgo_main.c")
+ fflg := creat("_cgo_flags")
+ for k, v := range p.CgoFlags {
+ fmt.Fprintf(fflg, "_CGO_%s=%s\n", k, v)
+ }
+ fflg.Close()
+
// Write C main file for using gcc to resolve imports.
fmt.Fprintf(fm, "int main() { return 0; }\n")
fmt.Fprintf(fm, "void crosscall2(void(*fn)(void*, int), void *a, int c) { }\n")
