From 9f5059b275af403da9f7dc4cc1af1f28d1ed53a9 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Tue, 31 Mar 2015 17:54:07 +0000
Subject: [PATCH] go/cmd/go: always link external test packages first

When linking complex packages that use both internal and external tests as well as many dependencies it is critical that the link order be external test package, internal test package, everything else.

This change is a back (forward?) port of the same change that canonical have been maintaining on their fork of the go tool for gccgo. Now that gccgo uses the go tool from upstream, this patch should be applied both to the gofrontend and golang/go repos.

From-SVN: r221800
---
 libgo/go/cmd/go/build.go | 9 ++++++++-
 libgo/go/cmd/go/pkg.go   | 1 +
 libgo/go/cmd/go/test.go  | 9 +++++----
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/libgo/go/cmd/go/build.go b/libgo/go/cmd/go/build.go
index 22d37f3fa3b..781a43b5d99 100644
--- a/libgo/go/cmd/go/build.go
+++ b/libgo/go/cmd/go/build.go
@@ -1921,6 +1921,7 @@ func (tools gccgoToolchain) ld(b *builder, p *Package, out string, allactions []
 	// and all LDFLAGS from cgo dependencies.
 	apackagesSeen := make(map[*Package]bool)
 	afiles := []string{}
+	xfiles := []string{}
 	ldflags := b.gccArchArgs()
 	cgoldflags := []string{}
 	usesCgo := false
@@ -1936,7 +1937,12 @@ func (tools gccgoToolchain) ld(b *builder, p *Package, out string, allactions []
 		if !a.p.Standard {
 			if a.p != nil && !apackagesSeen[a.p] {
 				apackagesSeen[a.p] = true
-				if a.p.fake {
+				if a.p.fake && a.p.external {
+					// external _tests, if present must come before
+					// internal _tests. Store these on a seperate list
+					// and place them at the head after this loop.
+					xfiles = append(xfiles, a.target)
+				} else if a.p.fake {
 					// move _test files to the top of the link order
 					afiles = append([]string{a.target}, afiles...)
 				} else {
@@ -1945,6 +1951,7 @@ func (tools gccgoToolchain) ld(b *builder, p *Package, out string, allactions []
 			}
 		}
 	}
+	afiles = append(xfiles, afiles...)
 
 	for _, a := range allactions {
 		if a.p != nil {
diff --git a/libgo/go/cmd/go/pkg.go b/libgo/go/cmd/go/pkg.go
index 62f6b4adf57..ef440dd3b74 100644
--- a/libgo/go/cmd/go/pkg.go
+++ b/libgo/go/cmd/go/pkg.go
@@ -83,6 +83,7 @@ type Package struct {
 	allgofiles   []string             // gofiles + IgnoredGoFiles, absolute paths
 	target       string               // installed file for this package (may be executable)
 	fake         bool                 // synthesized package
+	external     bool                 // synthesized external test package
 	forceBuild   bool                 // this package must be rebuilt
 	forceLibrary bool                 // this package is a library (even if named "main")
 	cmdline      bool                 // defined by files listed on command line
diff --git a/libgo/go/cmd/go/test.go b/libgo/go/cmd/go/test.go
index cc0a9acf45d..5cf7aaf0716 100644
--- a/libgo/go/cmd/go/test.go
+++ b/libgo/go/cmd/go/test.go
@@ -692,10 +692,11 @@ func (b *builder) test(p *Package) (buildAction, runAction, printAction *action,
 			build: &build.Package{
 				ImportPos: p.build.XTestImportPos,
 			},
-			imports: ximports,
-			pkgdir:  testDir,
-			fake:    true,
-			Stale:   true,
+			imports:  ximports,
+			pkgdir:   testDir,
+			fake:     true,
+			external: true,
+			Stale:    true,
 		}
 		if pxtestNeedsPtest {
 			pxtest.imports = append(pxtest.imports, ptest)
-- 
2.30.2