cmd/go: deduplicate gccgo afiles by package path, not *Package

This code was fixed a while ago to ensure that xtest and fake packages came
first on the link line, but golang.org/cl/16775 added --whole-archive ...
--no-whole-archive around all the .a files and rendered this fix useless.

So, take a different approach and only put one .a file on the linker command
line for each ImportPath we see while traversing the action graph, not for each
*Package we see. The way we walk the graph ensures that we'll see the .a files
that need to be first first.

Change-Id: I137f00f129ccc9fc99f40eee885cc04cc358a62e
Reviewed-on: https://go-review.googlesource.com/21692
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index 6b9da26ae8f2ef4af38cb5ca0870802295bf99b2..c0de2e069573e6f6b62227ff7548fc6fbd6e3d4d 100644 (file)
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -2602,10 +2602,9 @@ func (gccgoToolchain) pack(b *builder, p *Package, objDir, afile string, ofiles
 func (tools gccgoToolchain) ld(b *builder, root *action, 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)
+       apackagePathsSeen := make(map[string]bool)
        afiles := []string{}
        shlibs := []string{}
-       xfiles := []string{}
        ldflags := b.gccArchArgs()
        cgoldflags := []string{}
        usesCgo := false
@@ -2694,10 +2693,10 @@ func (tools gccgoToolchain) ld(b *builder, root *action, out string, allactions
                        // rather than the 'build' location (which may not exist any
                        // more). We still need to traverse the dependencies of the
                        // build action though so saying
-                       // if apackagesSeen[a.p] { return }
+                       // if apackagePathsSeen[a.p.ImportPath] { return }
                        // doesn't work.
-                       if !apackagesSeen[a.p] {
-                               apackagesSeen[a.p] = true
+                       if !apackagePathsSeen[a.p.ImportPath] {
+                               apackagePathsSeen[a.p.ImportPath] = true
                                target := a.target
                                if len(a.p.CgoFiles) > 0 {
                                        target, err = readAndRemoveCgoFlags(target)
@@ -2705,17 +2704,7 @@ func (tools gccgoToolchain) ld(b *builder, root *action, out string, allactions
                                                return
                                        }
                                }
-                               if a.p.fake && a.p.external {
-                                       // external _tests, if present must come before
-                                       // internal _tests. Store these on a separate list
-                                       // and place them at the head after this loop.
-                                       xfiles = append(xfiles, target)
-                               } else if a.p.fake {
-                                       // move _test files to the top of the link order
-                                       afiles = append([]string{target}, afiles...)
-                               } else {
-                                       afiles = append(afiles, target)
-                               }
+                               afiles = append(afiles, target)
                        }
                }
                if strings.HasSuffix(a.target, ".so") {
@@ -2735,7 +2724,6 @@ func (tools gccgoToolchain) ld(b *builder, root *action, out string, allactions
                        return err
                }
        }
-       afiles = append(xfiles, afiles...)
 
        for _, a := range allactions {
                // Gather CgoLDFLAGS, but not from standard packages.