Add 'gc_goopts' flag to command line to allow gc_goopts to propagate

BUILD.bazel

@@ -118,6 +118,7 @@ go_config(
         "//go/private:is_compilation_mode_dbg": "//go/private:always_true",
         "//conditions:default": "//go/config:debug",
     }),
+    gc_goopts = "//go/config:gc_goopts",
     gc_linkopts = "//go/config:gc_linkopts",
     gotags = "//go/config:tags",
     linkmode = "//go/config:linkmode",

go/config/BUILD.bazel

@@ -80,3 +80,9 @@ filegroup(
     srcs = glob(["**"]),
     visibility = ["//visibility:public"],
 )
+
+string_list_flag(
+    name = "gc_goopts",
+    build_setting_default = [],
+    visibility = ["//visibility:public"],
+)

go/private/actions/compilepkg.bzl

@@ -119,6 +119,8 @@ def emit_compilepkg(
         args.add("-testfilter", testfilter)
 
     gc_flags = list(gc_goopts)
+    if go.mode.gc_goopts:
+        gc_flags.extend(go.mode.gc_goopts)
     asm_flags = []
     if go.mode.race:
         gc_flags.append("-race")

go/private/context.bzl

@@ -391,6 +391,7 @@ def go_context(ctx, attr = None):
     stdlib = None
     coverdata = None
     nogo = None
+    gc_goopts = None
     if hasattr(attr, "_go_context_data"):
         go_context_data = _flatten_possibly_transitioned_attr(attr._go_context_data)
         if CgoContextInfo in go_context_data:
@@ -516,7 +517,7 @@ def go_context(ctx, attr = None):
         stamp = mode.stamp,
         label = ctx.label,
         cover_format = mode.cover_format,
-
+        gc_goopts = gc_goopts,
         # Action generators
         archive = toolchain.actions.archive,
         asm = toolchain.actions.asm,
@@ -821,6 +822,7 @@ def _go_config_impl(ctx):
         tags = ctx.attr.gotags[BuildSettingInfo].value,
         stamp = ctx.attr.stamp,
         cover_format = ctx.attr.cover_format[BuildSettingInfo].value,
+        gc_goopts = ctx.attr.gc_goopts[BuildSettingInfo].value,
         amd64 = ctx.attr.amd64,
     )]
 
@@ -868,6 +870,10 @@ go_config = rule(
             mandatory = True,
             providers = [BuildSettingInfo],
         ),
+        "gc_goopts": attr.label(
+            mandatory = True,
+            providers = [BuildSettingInfo],
+        ),
         "amd64": attr.string(),
     },
     provides = [GoConfigInfo],

go/private/mode.bzl

@@ -47,6 +47,8 @@ def mode_string(mode):
         result.append("stripped")
     if not result or not mode.link == LINKMODE_NORMAL:
         result.append(mode.link)
+    if mode.gc_goopts:
+        result.append(mode.gc_goopts)
     return "_".join(result)
 
 def _ternary(*values):
@@ -83,6 +85,7 @@ def get_mode(ctx, go_toolchain, cgo_context_info, go_config_info):
     amd64 = go_config_info.amd64 if go_config_info else None
     goos = go_toolchain.default_goos if getattr(ctx.attr, "goos", "auto") == "auto" else ctx.attr.goos
     goarch = go_toolchain.default_goarch if getattr(ctx.attr, "goarch", "auto") == "auto" else ctx.attr.goarch
+    gc_goopts = go_config_info.gc_goopts if go_config_info else ""
 
     # TODO(jayconrod): check for more invalid and contradictory settings.
     if pure and race:
@@ -116,6 +119,7 @@ def get_mode(ctx, go_toolchain, cgo_context_info, go_config_info):
         tags = tags,
         cover_format = cover_format,
         amd64 = amd64,
+        gc_goopts = gc_goopts,
     )
 
 def installsuffix(mode):