cmd/go: don't install most GOROOT .a files in pkg

[gostls13.git] / src / cmd / go / internal / work / build.go

diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index d27d114d912d6d9b4e47de68adf58d2904b33ba8..d8b78480718fa80ce3135cd564cd615424c6b7dd 100644 (file)
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -10,6 +10,7 @@ import (
        "flag"
        "fmt"
        "go/build"
+       "internal/buildinternal"
        "os"
        "os/exec"
        "path/filepath"
@@ -723,8 +724,6 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
        for _, p := range pkgs {
                if p.Target == "" {
                        switch {
-                       case p.Standard && p.ImportPath == "unsafe":
-                               // unsafe is a built-in package, has no target
                        case p.Name != "main" && p.Internal.Local && p.ConflictDir == "":
                                // Non-executables outside GOPATH need not have a target:
                                // we can use the cache to hold the built package archive for use in future builds.
@@ -732,6 +731,11 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
                                // or else something is wrong and worth reporting (like a ConflictDir).
                        case p.Name != "main" && p.Module != nil:
                                // Non-executables have no target (except the cache) when building with modules.
+                       case p.Name != "main" && p.Standard && !buildinternal.NeedsInstalledDotA(p.ImportPath):
+                               // Most packages in std do not need an installed .a, because they can be
+                               // rebuilt and used directly from the build cache.
+                               // A few targets (notably those using cgo) still do need to be installed
+                               // in case the user's environment lacks a C compiler.                   case p.Internal.GobinSubdir:
                        case p.Internal.GobinSubdir:
                                base.Errorf("go: cannot install cross-compiled binaries when GOBIN is set")
                        case p.Internal.CmdlineFiles: