Description: Fix linking order when testing.
Author: Michael Hudson-Doyle <michael.hudson@canonical.com>
Origin: vendor
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/gccgo-go/+bug/1381671
Forwarded: no
Last-Update: 2014-12-02
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -1705,7 +1705,6 @@
 func (tools gccgoToolchain) ld(b *builder, p *Package, out string, allactions []*action, mainpkg string, ofiles []string) error {
 	// gccgo needs explicit linking with all package dependencies,
 	// and all LDFLAGS from cgo dependencies.
-	apackagesSeen := make(map[*Package]bool)
 	afiles := []string{}
 	sfiles := []string{}
 	ldflags := b.gccArchArgs()
@@ -1713,22 +1712,26 @@
 	usesCgo := false
 	cxx := false
 
-	// Prefer the output of an install action to the output of a build action,
-	// because the install action will delete the output of the build action.
-	// Iterate over the list backward (reverse dependency order) so that we
-	// always see the install before the build.
+	// For a given package import path:
+	//   1) prefer a fake package (created by (*builder).test) to a real package
+	//   2) prefer the output of an install action to the output of a build action
+	//      because the install action will delete the output of the build
+	//      action
+	// Iterating over the list backwards (reverse dependency order) ensures that we
+	// always see an install before a build.
+	importPathsSeen := make(map[string]bool)
 	for i := len(allactions) - 1; i >= 0; i-- {
 		a := allactions[i]
-		if !a.p.Standard {
-			if a.p != nil && !apackagesSeen[a.p] {
-				apackagesSeen[a.p] = true
-				if a.p.fake {
-					// move _test files to the top of the link order
-					afiles = append([]string{a.target}, afiles...)
-				} else {
-					afiles = append(afiles, a.target)
-				}
-			}
+		if a.p != nil && a.p.fake && !importPathsSeen[a.p.ImportPath] {
+			importPathsSeen[a.p.ImportPath] = true
+			afiles = append(afiles, a.target)
+		}
+	}
+	for i := len(allactions) - 1; i >= 0; i-- {
+		a := allactions[i]
+		if a.p != nil && !a.p.Standard && !importPathsSeen[a.p.ImportPath] {
+			importPathsSeen[a.p.ImportPath] = true
+			afiles = append(afiles, a.target)
 		}
 	}