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-rw-r--r--loader/cgo.go76
-rw-r--r--loader/libclang.go112
-rw-r--r--testdata/cgo/main.h6
3 files changed, 137 insertions, 57 deletions
diff --git a/loader/cgo.go b/loader/cgo.go
index c88f61c48..342a2af1b 100644
--- a/loader/cgo.go
+++ b/loader/cgo.go
@@ -23,6 +23,7 @@ type fileInfo struct {
typedefs map[string]*typedefInfo
elaboratedTypes map[string]ast.Expr
importCPos token.Pos
+ missingSymbols map[string]struct{}
}
// functionInfo stores some information about a Cgo function found by libclang
@@ -51,16 +52,31 @@ type globalInfo struct {
// cgoAliases list type aliases between Go and C, for types that are equivalent
// in both languages. See addTypeAliases.
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.__builtin_va_list": "uintptr", // dummy value until fully implemented
+ "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",
+}
+
+// cgoBuiltinAliases are handled specially because they only exist on the Go
+// side of CGo, not on the CGo (they're prefixed with "_Cgo_" there).
+var cgoBuiltinAliases = map[string]struct{}{
+ "char": struct{}{},
+ "schar": struct{}{},
+ "uchar": struct{}{},
+ "short": struct{}{},
+ "ushort": struct{}{},
+ "int": struct{}{},
+ "uint": struct{}{},
+ "long": struct{}{},
+ "ulong": struct{}{},
+ "longlong": struct{}{},
+ "ulonglong": struct{}{},
}
// cgoTypes lists some C types with ambiguous sizes that must be retrieved
@@ -91,6 +107,13 @@ func (p *Package) processCgo(filename string, f *ast.File, cflags []string) []er
globals: map[string]*globalInfo{},
typedefs: map[string]*typedefInfo{},
elaboratedTypes: map[string]ast.Expr{},
+ missingSymbols: map[string]struct{}{},
+ }
+
+ // Find all C.* symbols.
+ f = astutil.Apply(f, info.findMissingCGoNames, nil).(*ast.File)
+ for name := range cgoBuiltinAliases {
+ info.missingSymbols["_Cgo_"+name] = struct{}{}
}
// Find `import "C"` statements in the file.
@@ -222,6 +245,9 @@ func (info *fileInfo) addFuncDecls() {
// // ...
// )
func (info *fileInfo) addFuncPtrDecls() {
+ if len(info.functions) == 0 {
+ return
+ }
gen := &ast.GenDecl{
TokPos: info.importCPos,
Tok: token.VAR,
@@ -270,6 +296,9 @@ func (info *fileInfo) addFuncPtrDecls() {
// // ...
// )
func (info *fileInfo) addVarDecls() {
+ if len(info.globals) == 0 {
+ return
+ }
gen := &ast.GenDecl{
TokPos: info.importCPos,
Tok: token.VAR,
@@ -346,6 +375,9 @@ func (info *fileInfo) addTypeAliases() {
}
func (info *fileInfo) addTypedefs() {
+ if len(info.typedefs) == 0 {
+ return
+ }
gen := &ast.GenDecl{
TokPos: info.importCPos,
Tok: token.TYPE,
@@ -394,6 +426,9 @@ func (info *fileInfo) addTypedefs() {
// See also:
// https://en.cppreference.com/w/cpp/language/elaborated_type_specifier
func (info *fileInfo) addElaboratedTypes() {
+ if len(info.elaboratedTypes) == 0 {
+ return
+ }
gen := &ast.GenDecl{
TokPos: info.importCPos,
Tok: token.TYPE,
@@ -424,6 +459,27 @@ func (info *fileInfo) addElaboratedTypes() {
info.Decls = append(info.Decls, gen)
}
+// findMissingCGoNames traverses the AST and finds all C.something names. Only
+// these symbols are extracted from the parsed C AST and converted to the Go
+// equivalent.
+func (info *fileInfo) findMissingCGoNames(cursor *astutil.Cursor) bool {
+ switch node := cursor.Node().(type) {
+ case *ast.SelectorExpr:
+ x, ok := node.X.(*ast.Ident)
+ if !ok {
+ return true
+ }
+ if x.Name == "C" {
+ name := node.Sel.Name
+ if _, ok := cgoBuiltinAliases[name]; ok {
+ name = "_Cgo_" + name
+ }
+ info.missingSymbols[name] = struct{}{}
+ }
+ }
+ return true
+}
+
// walker replaces all "C".<something> expressions to literal "C.<something>"
// expressions. Such expressions are impossible to write in Go (a dot cannot be
// used in the middle of a name) so in practice all C identifiers live in a
diff --git a/loader/libclang.go b/loader/libclang.go
index a69bf9933..4292ed884 100644
--- a/loader/libclang.go
+++ b/loader/libclang.go
@@ -168,6 +168,9 @@ func tinygo_clang_globals_visitor(c, parent C.GoCXCursor, client_data C.CXClient
switch kind {
case C.CXCursor_FunctionDecl:
name := getString(C.tinygo_clang_getCursorSpelling(c))
+ if _, required := info.missingSymbols[name]; !required {
+ return C.CXChildVisit_Continue
+ }
cursorType := C.tinygo_clang_getCursorType(c)
if C.clang_isFunctionTypeVariadic(cursorType) != 0 {
return C.CXChildVisit_Continue // not supported
@@ -199,58 +202,23 @@ func tinygo_clang_globals_visitor(c, parent C.GoCXCursor, client_data C.CXClient
}
case C.CXCursor_StructDecl:
typ := C.tinygo_clang_getCursorType(c)
+ name := getString(C.tinygo_clang_getCursorSpelling(c))
+ if _, required := info.missingSymbols["struct_"+name]; !required {
+ return C.CXChildVisit_Continue
+ }
info.makeASTType(typ, pos)
case C.CXCursor_TypedefDecl:
typedefType := C.tinygo_clang_getCursorType(c)
name := getString(C.clang_getTypedefName(typedefType))
- underlyingType := C.tinygo_clang_getTypedefDeclUnderlyingType(c)
- expr := info.makeASTType(underlyingType, pos)
- if strings.HasPrefix(name, "_Cgo_") {
- expr := expr.(*ast.Ident)
- typeSize := C.clang_Type_getSizeOf(underlyingType)
- switch expr.Name {
- case "C.char":
- if typeSize != 1 {
- // This happens for some very special purpose architectures
- // (DSPs etc.) that are not currently targeted.
- // https://www.embecosm.com/2017/04/18/non-8-bit-char-support-in-clang-and-llvm/
- panic("unknown char width")
- }
- switch underlyingType.kind {
- case C.CXType_Char_S:
- expr.Name = "int8"
- case C.CXType_Char_U:
- expr.Name = "uint8"
- }
- case "C.schar", "C.short", "C.int", "C.long", "C.longlong":
- switch typeSize {
- case 1:
- expr.Name = "int8"
- case 2:
- expr.Name = "int16"
- case 4:
- expr.Name = "int32"
- case 8:
- expr.Name = "int64"
- }
- case "C.uchar", "C.ushort", "C.uint", "C.ulong", "C.ulonglong":
- switch typeSize {
- case 1:
- expr.Name = "uint8"
- case 2:
- expr.Name = "uint16"
- case 4:
- expr.Name = "uint32"
- case 8:
- expr.Name = "uint64"
- }
- }
- }
- info.typedefs[name] = &typedefInfo{
- typeExpr: expr,
+ if _, required := info.missingSymbols[name]; !required {
+ return C.CXChildVisit_Continue
}
+ info.makeASTType(typedefType, pos)
case C.CXCursor_VarDecl:
name := getString(C.tinygo_clang_getCursorSpelling(c))
+ if _, required := info.missingSymbols[name]; !required {
+ return C.CXChildVisit_Continue
+ }
cursorType := C.tinygo_clang_getCursorType(c)
info.globals[name] = &globalInfo{
typeExpr: info.makeASTType(cursorType, pos),
@@ -394,10 +362,60 @@ func (info *fileInfo) makeASTType(typ C.CXType, pos token.Pos) ast.Expr {
},
}
case C.CXType_Typedef:
- typedefName := getString(C.clang_getTypedefName(typ))
+ name := getString(C.clang_getTypedefName(typ))
+ if _, ok := info.typedefs[name]; !ok {
+ info.typedefs[name] = nil // don't recurse
+ c := C.tinygo_clang_getTypeDeclaration(typ)
+ underlyingType := C.tinygo_clang_getTypedefDeclUnderlyingType(c)
+ expr := info.makeASTType(underlyingType, pos)
+ if strings.HasPrefix(name, "_Cgo_") {
+ expr := expr.(*ast.Ident)
+ typeSize := C.clang_Type_getSizeOf(underlyingType)
+ switch expr.Name {
+ case "C.char":
+ if typeSize != 1 {
+ // This happens for some very special purpose architectures
+ // (DSPs etc.) that are not currently targeted.
+ // https://www.embecosm.com/2017/04/18/non-8-bit-char-support-in-clang-and-llvm/
+ panic("unknown char width")
+ }
+ switch underlyingType.kind {
+ case C.CXType_Char_S:
+ expr.Name = "int8"
+ case C.CXType_Char_U:
+ expr.Name = "uint8"
+ }
+ case "C.schar", "C.short", "C.int", "C.long", "C.longlong":
+ switch typeSize {
+ case 1:
+ expr.Name = "int8"
+ case 2:
+ expr.Name = "int16"
+ case 4:
+ expr.Name = "int32"
+ case 8:
+ expr.Name = "int64"
+ }
+ case "C.uchar", "C.ushort", "C.uint", "C.ulong", "C.ulonglong":
+ switch typeSize {
+ case 1:
+ expr.Name = "uint8"
+ case 2:
+ expr.Name = "uint16"
+ case 4:
+ expr.Name = "uint32"
+ case 8:
+ expr.Name = "uint64"
+ }
+ }
+ }
+ info.typedefs[name] = &typedefInfo{
+ typeExpr: expr,
+ }
+ }
return &ast.Ident{
NamePos: pos,
- Name: "C." + typedefName,
+ Name: "C." + name,
}
case C.CXType_Elaborated:
underlying := C.clang_Type_getNamedType(typ)
diff --git a/testdata/cgo/main.h b/testdata/cgo/main.h
index 117f907a2..0659ab0cc 100644
--- a/testdata/cgo/main.h
+++ b/testdata/cgo/main.h
@@ -2,12 +2,17 @@
#include <stdint.h>
typedef short myint;
+typedef short unusedTypedef;
int add(int a, int b);
+int unusedFunction(void);
typedef int (*binop_t) (int, int);
int doCallback(int a, int b, binop_t cb);
typedef int * intPointer;
void store(int value, int *ptr);
+// this signature should not be included by CGo
+void unusedFunction2(int x, __builtin_va_list args);
+
typedef struct collection {
short s;
long l;
@@ -37,6 +42,7 @@ void unionSetData(short f0, short f1, short f2);
// test globals and datatypes
extern int global;
+extern int unusedGlobal;
extern bool globalBool;
extern bool globalBool2;
extern float globalFloat;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 16:42:13 +0000