cgo: refactor Go types a little bit

cgo/cgo.go

@@ -75,19 +75,10 @@ type bitfieldInfo struct {
 }
 
 // cgoAliases list type aliases between Go and C, for types that are equivalent
-// in both languages. See addTypeAliases.
+// in both languages.
 var cgoAliases = map[string]string{
-	"C.int8_t":    "int8",
-	"C.int16_t":   "int16",
-	"C.int32_t":   "int32",
-	"C.int64_t":   "int64",
-	"C.uint8_t":   "uint8",
-	"C.uint16_t":  "uint16",
-	"C.uint32_t":  "uint32",
-	"C.uint64_t":  "uint64",
-	"C.uintptr_t": "uintptr",
-	"C.float":     "float32",
-	"C.double":    "float64",
+	"float":  "float32",
+	"double": "float64",
 }
 
 // builtinAliases are handled specially because they only exist on the Go side
@@ -311,10 +302,11 @@ func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cfl
 	// Process CGo imports for each file.
 	for i, f := range files {
 		cf := p.newCGoFile(f, i)
-		// Float and double are aliased, meaning that C.float is the same thing
-		// as float32 in Go.
-		cf.names["float"] = clangCursor{}
-		cf.names["double"] = clangCursor{}
+		// These types are aliased with the corresponding types in C. For
+		// example, float in C is always float32 in Go.
+		for name := range cgoAliases {
+			cf.names[name] = clangCursor{}
+		}
 		// Now read all the names (identifies) that C defines in the header
 		// snippet.
 		cf.readNames(p.cgoHeaders[i], cflagsForCGo, filepath.Base(fset.File(f.Pos()).Name()), func(names map[string]clangCursor) {
@@ -1129,9 +1121,7 @@ func (p *cgoPackage) getUnnamedDeclName(prefix string, itf interface{}) string {
 // getASTDeclName will declare the given C AST node (if not already defined) and
 // will return its name, in the form of C.foo.
 func (f *cgoFile) getASTDeclName(name string, found clangCursor, iscall bool) string {
-	// Some types are defined in stdint.h and map directly to a particular Go
-	// type.
-	if alias := cgoAliases["C."+name]; alias != "" {
+	if alias := cgoAliases[name]; alias != "" {
 		return alias
 	}
 	node := f.getASTDeclNode(name, found, iscall)

cgo/testdata/errors.go

@@ -22,8 +22,12 @@ import "C"
 // #warning another warning
 import "C"
 
+// #include <stdint.h>
+import "C"
+
 // Make sure that errors for the following lines won't change with future
 // additions to the CGo preamble.
+//
 //line errors.go:100
 var (
 	// constant too large
@@ -38,4 +42,8 @@ var (
 	_ byte = C.SOME_CONST_3
 
 	_ = C.SOME_CONST_4
+
+	// This must result in a type error. Previously, TinyGo would allow this
+	// code (which is not allowed by upstream Go).
+	_ int8 = C.int8_t(5)
 )

cgo/testdata/errors.out.go

@@ -11,6 +11,7 @@
 //     testdata/errors.go:108: undefined: C.SOME_CONST_1
 //     testdata/errors.go:110: cannot use C.SOME_CONST_3 (untyped int constant 1234) as byte value in variable declaration (overflows)
 //     testdata/errors.go:112: undefined: C.SOME_CONST_4
+//     testdata/errors.go:116: cannot use C.int8_t(5) (constant 5 of type C.schar) as int8 value in variable declaration
 
 package main
 
@@ -58,3 +59,5 @@ type C.struct_point_t struct {
 type C.point_t = C.struct_point_t
 
 const C.SOME_CONST_3 = 1234
+
+type C.int8_t = C.schar

testdata/cgo/main.go

@@ -52,10 +52,6 @@ func main() {
 	println("static headerfunc:", C.headerfunc_static(5))
 	headerfunc_2()
 
-	// equivalent types
-	var goInt8 int8 = 5
-	var _ C.int8_t = goInt8
-
 	// more globals
 	println("bool:", C.globalBool, C.globalBool2 == true)
 	println("float:", C.globalFloat)