miqt/cmd/genbindings/clangexec.go
2024-08-15 19:51:31 +12:00

131 lines
2.9 KiB
Go

package main
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"os/exec"
"sync"
)
func clangExec(ctx context.Context, clangBin, inputHeader string, cflags []string) ([]interface{}, error) {
clangArgs := []string{`-x`, `c++`}
clangArgs = append(clangArgs, cflags...)
clangArgs = append(clangArgs, `-Xclang`, `-ast-dump=json`, `-fsyntax-only`, inputHeader)
cmd := exec.CommandContext(ctx, clangBin, clangArgs...)
pr, err := cmd.StdoutPipe()
if err != nil {
return nil, fmt.Errorf("StdoutPipe: %w", err)
}
err = cmd.Start()
if err != nil {
return nil, fmt.Errorf("Start: %w", err)
}
var wg sync.WaitGroup
var inner []interface{}
wg.Add(1)
go func() {
defer wg.Done()
inner__, err := clangStripUpToFile(pr, inputHeader)
if err != nil {
panic(err)
}
inner = inner__
}()
err = cmd.Wait()
if err != nil {
panic(err)
}
wg.Wait()
return inner, nil
}
// clangStripUpToFile strips all AST nodes from the clang output until we find
// one that really originated in the source file.
// This cleans out everything in the translation unit that came from an
// #included file.
// @ref https://stackoverflow.com/a/71128654
func clangStripUpToFile(stdout io.Reader, inputFilePath string) ([]interface{}, error) {
var obj = map[string]interface{}{}
err := json.NewDecoder(stdout).Decode(&obj)
if err != nil {
return nil, fmt.Errorf("json.Decode: %v", err)
}
inner, ok := obj["inner"].([]interface{})
if !ok {
return nil, errors.New("no inner")
}
// This can't be done by matching the first position only, since it's possible
// that there are more #include<>s further down the file
ret := make([]interface{}, 0, len(inner))
for _, entry := range inner {
entry, ok := entry.(map[string]interface{})
if !ok {
return nil, errors.New("entry is not a map")
}
if _, ok := entry["isImplicit"]; ok {
// Don't keep
continue
}
var match_filename = ""
if loc, ok := entry["loc"].(map[string]interface{}); ok {
if includedFrom, ok := loc["includedFrom"].(map[string]interface{}); ok {
if filename, ok := includedFrom["file"].(string); ok {
match_filename = filename
}
}
if match_filename == "" {
if expansionloc, ok := loc["expansionLoc"].(map[string]interface{}); ok {
if filename, ok := expansionloc["file"].(string); ok {
match_filename = filename
} else if includedFrom, ok := expansionloc["includedFrom"].(map[string]interface{}); ok {
if filename, ok := includedFrom["file"].(string); ok {
match_filename = filename
}
}
}
}
} else {
return nil, errors.New("no loc")
}
// log.Printf("# name=%v kind=%v filename=%q\n", entry["name"], entry["kind"], match_filename)
if match_filename == "" {
// Keep
ret = append(ret, entry)
} else if match_filename != inputFilePath {
// Skip this
} else {
// Keep this
// ret = append(ret, entry)
}
}
return ret, nil
}