go: make compiler usable for cross compiles #50223
Conversation
GrahamcOfBorg
added
6.topic: golang
10.rebuild-darwin: 0
| @@ -133,12 +133,12 @@ stdenv.mkDerivation rec { | |||
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| GOOS = if stdenv.isDarwin then "darwin" else "linux"; | |||
| GOARCH = if stdenv.isDarwin then "amd64" | |||
| else if stdenv.targetPlatform.isi686 then "386" | |||
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This should be correct. GOARCH is the architecture that the go compiler will produce code /for/. targetPlatform is used correctly here. The stdenv.isDarwin stuff looks wrong though. We should be able to use targetPlatform.parsed.kernel.name for GOOS and a simple map for GOARCH:
GOOS = targetPlatform.parsed.kernel.name;
GOARCH = {
"i686" = "386";
"x86_64" = "amd64";
"aarch64" = "arm64";
"arm" = "arm";
"armv5tel" = "arm";
"armv6l" = "arm";
"armv7l" = "arm";
}.${stdenv.targetPlatform.parsed.cpu.name} or (throw "Unsupported system");
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The go compiler, after it's built, is able to produce code for any platform by changing those environment variables. So you'd set those appropriately for the host platform when doing a cross compile of a go package like terraform. But when building the go compiler itself, setting it to anything other than the build platform results in "invalid instruction" build errors.
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Makes sense, but that restructuring that Matt wrote (the "switch-case") is also a good idea.
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Updated to use the switch-case version
Motivation for this change
Allow go compiler to be used in cross compiles
This makes the go compiler usable for cross compiles. Previously, specifying go as
nativeBuildsInputsordepsBuildBuilddependencies resulted in a go compiler built for the wrong platform. Now it pulls in the appropriate build platform version.I don't think
buildGoPackagesupports cross compiles, so existing go packages liketerraformwill still not cross compile. But one could now manually set up a go build that cross compiles without usingbuildGoPackage.And go itself currently doesn't seem to cross compile; this PR doesn't change that.
Things done
sandboxinnix.confon non-NixOS)nix-shell -p nox --run "nox-review wip"./result/bin/)nix path-info -Sbefore and after)