testscript: add gc and gccgo conditions

gotooltest/setup.go

@@ -106,12 +106,6 @@ func Setup(p *testscript.Params) error {
 	p.Cmds["go"] = cmdGo
 	origCondition := p.Condition
 	p.Condition = func(cond string) (bool, error) {
-		if cond == "gc" || cond == "gccgo" {
-			// TODO this reflects the compiler that the current
-			// binary was built with but not necessarily the compiler
-			// that will be used.
-			return cond == runtime.Compiler, nil
-		}
 		if goVersionRegex.MatchString(cond) {
 			for _, v := range build.Default.ReleaseTags {
 				if cond == v {

testscript/doc.go

@@ -105,6 +105,8 @@ should only run when the condition is satisfied. The predefined conditions are:
  - [link] for whether the OS has hard link support
  - [symlink] for whether the OS has symbolic link support
  - [exec:prog] for whether prog is available for execution (found by exec.LookPath)
+ - [gc] for whether Go was built with gc
+ - [gccgo] for whether Go was built with gccgo
 
 A condition can be negated: [!short] means to run the rest of the line
 when testing.Short() is false.

testscript/testdata/cond.txt

@@ -0,0 +1,6 @@
+[!exec:sh] skip 'sh not found in $PATH'
+
+# test that exactly one of gc and gccgo is set
+[gc] exec sh -c 'echo gc >> go-compiler'
+[gccgo] exec sh -c 'echo gccgo >> go-compiler'
+grep '\A(gc|gccgo)\n\z' go-compiler

testscript/testscript.go

@@ -592,6 +592,11 @@ func (ts *TestScript) condition(cond string) (bool, error) {
 			return err == nil
 		}).(bool)
 		return ok, nil
+	case cond == "gc" || cond == "gccgo":
+		// TODO this reflects the compiler that the current
+		// binary was built with but not necessarily the compiler
+		// that will be used.
+		return cond == runtime.Compiler, nil
 	case ts.params.Condition != nil:
 		return ts.params.Condition(cond)
 	default: