main: improve support for x86-32 and add tests

To avoid breaking this, make sure we actually test x86-32 (aka i386 aka
GOARCH=386) support in CI.

Also remove the now-unnecessary binutils-arm-none-eabi package to speed
up CI a bit.

.circleci/config.yml

@@ -28,6 +28,7 @@ commands:
                 qemu-user \
                 gcc-avr \
                 avr-libc
+            sudo apt-get install --no-install-recommends libc6-dev-i386 lib32gcc-8-dev
   install-node:
     steps:
       - run:
@@ -133,7 +134,6 @@ commands:
           command: |
             sudo apt-get install \
                 gcc-arm-linux-gnueabihf \
-                binutils-arm-none-eabi \
                 libc6-dev-armel-cross \
                 gcc-aarch64-linux-gnu \
                 libc6-dev-arm64-cross \
@@ -141,6 +141,7 @@ commands:
                 qemu-user \
                 gcc-avr \
                 avr-libc
+            sudo apt-get install --no-install-recommends libc6-dev-i386 lib32gcc-6-dev
       - install-node
       - install-wasmtime
       - install-xtensa-toolchain:
@@ -194,7 +195,6 @@ commands:
           command: |
             sudo apt-get install \
                 gcc-arm-linux-gnueabihf \
-                binutils-arm-none-eabi \
                 libc6-dev-armel-cross \
                 gcc-aarch64-linux-gnu \
                 libc6-dev-arm64-cross \
@@ -202,6 +202,7 @@ commands:
                 qemu-user \
                 gcc-avr \
                 avr-libc
+            sudo apt-get install --no-install-recommends libc6-dev-i386 lib32gcc-6-dev
       - install-node
       - install-wasmtime
       - install-xtensa-toolchain:

compileopts/target.go

@@ -215,6 +215,7 @@ func LoadTarget(target string) (*TargetSpec, error) {
 		}
 		goarch := map[string]string{ // map from LLVM arch to Go arch
 			"i386":    "386",
+			"i686":    "386",
 			"x86_64":  "amd64",
 			"aarch64": "arm64",
 			"armv7":   "arm",
@@ -260,9 +261,9 @@ func defaultTarget(goos, goarch, triple string) (*TargetSpec, error) {
 			spec.GDB = "aarch64-linux-gnu-gdb"
 			spec.Emulator = []string{"qemu-aarch64", "-L", "/usr/aarch64-linux-gnu"}
 		}
-		if goarch == "386" {
-			spec.CFlags = []string{"-m32"}
-			spec.LDFlags = []string{"-m32"}
+		if goarch == "386" && runtime.GOARCH == "amd64" {
+			spec.CFlags = append(spec.CFlags, "-m32")
+			spec.LDFlags = append(spec.LDFlags, "-m32")
 		}
 	}
 	return &spec, nil

main_test.go

@@ -78,6 +78,9 @@ func TestCompiler(t *testing.T) {
 	}
 
 	if runtime.GOOS == "linux" {
+		t.Run("X86Linux", func(t *testing.T) {
+			runPlatTests("i386--linux-gnu", matches, t)
+		})
 		t.Run("ARMLinux", func(t *testing.T) {
 			runPlatTests("arm--linux-gnueabihf", matches, t)
 		})
@@ -189,11 +192,12 @@ func runTest(path, target string, t *testing.T) {
 			t.Fatal("failed to load target spec:", err)
 		}
 		if len(spec.Emulator) == 0 {
-			t.Fatal("no emulator available for target:", target)
-		}
+			cmd = exec.Command(binary)
+		} else {
 			args := append(spec.Emulator[1:], binary)
 			cmd = exec.Command(spec.Emulator[0], args...)
 		}
+	}
 	stdout := &bytes.Buffer{}
 	cmd.Stdout = stdout
 	cmd.Stderr = os.Stderr