From 551d8b9ff5b64bded6a7dd284fb1790a2f78ead0 Mon Sep 17 00:00:00 2001
From: Shenghou Ma <minux.ma@gmail.com>
Date: Fri, 17 Aug 2012 03:42:34 +0800
Subject: [PATCH] cmd/go: new cgo build procedure    This CL adds a step to the
 build procedure for cgo programs. It uses 'ld -r' to combine all gcc compiled
 object file and generate a relocatable object file for our ld. Additionally,
 this linking step will combine some static linking gcc library into the
 relocatable object file, so that we can use libgcc, libmingwex and libmingw32
 without problem.

   Fixes #3261.
   Fixes #1741.
   Added a testcase for linking in libgcc.

TODO:
1. still need to fix the INDIRECT_SYMBOL_LOCAL problem on Darwin/386.
2. still need to enable the libgcc test on Linux/ARM, because 5l can't deal
with thumb libgcc.

Tested on Darwin/amd64, Darwin/386, FreeBSD/amd64, FreeBSD/386, Linux/amd64,
Linux/386, Linux/ARM, Windows/amd64, Windows/386

R=iant, rsc, bradfitz, coldredlemur
CC=golang-dev
https://golang.org/cl/5822049
---
 misc/cgo/test/cgo_test.go                     |  1 +
 misc/cgo/test/issue3261.go                    | 43 +++++++++++++++++++
 ...{sleep_windows.go => sleep_windows_386.go} |  4 ++
 src/cmd/go/build.go                           | 33 +++++++++++++-
 src/run.bat                                   |  8 +++-
 5 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 misc/cgo/test/issue3261.go
 rename misc/cgo/test/{sleep_windows.go => sleep_windows_386.go} (61%)

diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index 34beee69d19..9c3c1163453 100644
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -27,5 +27,6 @@ func Test1328(t *testing.T)                { test1328(t) }
 func TestParallelSleep(t *testing.T)       { testParallelSleep(t) }
 func TestSetEnv(t *testing.T)              { testSetEnv(t) }
 func TestHelpers(t *testing.T)             { testHelpers(t) }
+func TestLibgcc(t *testing.T)              { testLibgcc(t) }
 
 func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }
diff --git a/misc/cgo/test/issue3261.go b/misc/cgo/test/issue3261.go
new file mode 100644
index 00000000000..0411be892df
--- /dev/null
+++ b/misc/cgo/test/issue3261.go
@@ -0,0 +1,43 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cgotest
+
+/*
+// libgcc on ARM might be compiled as thumb code, but our 5l
+// can't handle that, so we have to disable this test on arm.
+#ifdef __ARMEL__
+#include <stdio.h>
+int vabs(int x) {
+	puts("testLibgcc is disabled on ARM because 5l cannot handle thumb library.");
+	return (x < 0) ? -x : x;
+}
+#else
+int __absvsi2(int); // dummy prototype for libgcc function
+// we shouldn't name the function abs, as gcc might use
+// the builtin one.
+int vabs(int x) { return __absvsi2(x); }
+#endif
+*/
+import "C"
+
+import "testing"
+
+func testLibgcc(t *testing.T) {
+	var table = []struct {
+		in, out C.int
+	}{
+		{0, 0},
+		{1, 1},
+		{-42, 42},
+		{1000300, 1000300},
+		{1 - 1<<31, 1<<31 - 1},
+	}
+	for _, v := range table {
+		if o := C.vabs(v.in); o != v.out {
+			t.Fatalf("abs(%d) got %d, should be %d", v.in, o, v.out)
+			return
+		}
+	}
+}
diff --git a/misc/cgo/test/sleep_windows.go b/misc/cgo/test/sleep_windows_386.go
similarity index 61%
rename from misc/cgo/test/sleep_windows.go
rename to misc/cgo/test/sleep_windows_386.go
index 007a1bb4c80..75687d7831a 100644
--- a/misc/cgo/test/sleep_windows.go
+++ b/misc/cgo/test/sleep_windows_386.go
@@ -5,6 +5,10 @@
 package cgotest
 
 /*
+// mingw32 on windows/386 provides usleep() but not sleep(),
+// as we don't want to require all other OSes to provide usleep,
+// we emulate sleep(int s) using win32 API Sleep(int ms).
+
 #include <windows.h>
 
 unsigned int sleep(unsigned int seconds) {
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index ff5e0b9c3f3..e12698f9f01 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -1558,6 +1558,24 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
 
 	// gcc
 	var linkobj []string
+
+	var bareLDFLAGS []string
+	// filter out -lsomelib, and -framework X if on Darwin
+	for i := 0; i < len(cgoLDFLAGS); i++ {
+		f := cgoLDFLAGS[i]
+		if !strings.HasPrefix(f, "-l") {
+			if goos == "darwin" && f == "-framework" { // skip the -framework X
+				i += 1
+				continue
+			}
+			bareLDFLAGS = append(bareLDFLAGS, f)
+		}
+	}
+	staticLibs := []string{"-lgcc"}
+	if goos == "windows" {
+		staticLibs = append(staticLibs, "-lmingwex", "-lmingw32")
+	}
+
 	for _, cfile := range cfiles {
 		ofile := obj + cfile[:len(cfile)-1] + "o"
 		if err := b.gcc(p, ofile, cgoCFLAGS, obj+cfile); err != nil {
@@ -1605,10 +1623,23 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
 		return nil, nil, err
 	}
 
+	ofile := obj + "_all.o"
+	var gccObjs, nonGccObjs []string
+	for _, f := range outObj {
+		if strings.HasSuffix(f, ".o") {
+			gccObjs = append(gccObjs, f)
+		} else {
+			nonGccObjs = append(nonGccObjs, f)
+		}
+	}
+	if err := b.gccld(p, ofile, stringList(bareLDFLAGS, "-Wl,-r", "-nostdlib", staticLibs), gccObjs); err != nil {
+		return nil, nil, err
+	}
+
 	// NOTE(rsc): The importObj is a 5c/6c/8c object and on Windows
 	// must be processed before the gcc-generated objects.
 	// Put it first.  http://golang.org/issue/2601
-	outObj = append([]string{importObj}, outObj...)
+	outObj = stringList(importObj, nonGccObjs, ofile)
 
 	return outGo, outObj, nil
 }
diff --git a/src/run.bat b/src/run.bat
index 496cbe3d577..36d24984e9a 100644
--- a/src/run.bat
+++ b/src/run.bat
@@ -64,12 +64,18 @@ echo.
 ::echo.
 
 :: cgo tests
-:: TODO: Other cgo tests
 if x%CGO_ENABLED% == x0 goto nocgo
 echo # ..\misc\cgo\life
 go run %GOROOT%\test\run.go - ..\misc\cgo\life
 if errorlevel 1 goto fail
 echo.
+
+:: TODO ..\misc\cgo\stdio
+
+echo # ..\misc\cgo\test
+go test ..\misc\cgo\test
+if errorlevel 1 goto fail
+echo.
 :nocgo
 
 :: TODO: The other tests in run.bash.