From 6cacafb8dc0351c2204cefedcd83864df6591d3d Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Fri, 30 Nov 2018 13:01:20 +0100
Subject: [PATCH] cgo: add package directory to header include paths

---
 compiler/compiler.go |  4 +++-
 loader/cgo.go        |  4 ++--
 loader/libclang.go   | 14 ++++++++++++--
 loader/loader.go     |  3 ++-
 main.go              |  1 +
 testdata/cgo/main.c  |  2 ++
 testdata/cgo/main.go |  3 +--
 testdata/cgo/main.h  |  2 ++
 8 files changed, 25 insertions(+), 8 deletions(-)
 create mode 100644 testdata/cgo/main.h

diff --git a/compiler/compiler.go b/compiler/compiler.go
index 8b5adab6..2d621249 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -32,6 +32,7 @@ func init() {
 type Config struct {
 	Triple     string   // LLVM target triple, e.g. x86_64-unknown-linux-gnu (empty string means default)
 	GC         string   // garbage collection strategy
+	CFlags     []string // flags to pass to cgo
 	DumpSSA    bool     // dump Go SSA, for compiler debugging
 	Debug      bool     // add debug symbols for gdb
 	RootDir    string   // GOROOT for TinyGo
@@ -208,7 +209,8 @@ func (c *Compiler) Compile(mainPath string) error {
 				MaxAlign: int64(c.targetData.PrefTypeAlignment(c.i8ptrType)),
 			},
 		},
-		Dir: wd,
+		Dir:    wd,
+		CFlags: c.CFlags,
 	}
 	if strings.HasSuffix(mainPath, ".go") {
 		_, err = lprogram.ImportFile(mainPath)
diff --git a/loader/cgo.go b/loader/cgo.go
index 3678526c..f95e578b 100644
--- a/loader/cgo.go
+++ b/loader/cgo.go
@@ -73,7 +73,7 @@ typedef unsigned long long  _Cgo_ulonglong;
 
 // processCgo extracts the `import "C"` statement from the AST, parses the
 // comment with libclang, and modifies the AST to use this information.
-func (p *Package) processCgo(filename string, f *ast.File) error {
+func (p *Package) processCgo(filename string, f *ast.File, cflags []string) error {
 	info := &fileInfo{
 		File:     f,
 		filename: filename,
@@ -106,7 +106,7 @@ func (p *Package) processCgo(filename string, f *ast.File) error {
 		// source location.
 		info.importCPos = spec.Path.ValuePos
 
-		err = info.parseFragment(cgoComment + cgoTypes)
+		err = info.parseFragment(cgoComment+cgoTypes, cflags)
 		if err != nil {
 			return err
 		}
diff --git a/loader/libclang.go b/loader/libclang.go
index 9f3b444d..ae3ae8ab 100644
--- a/loader/libclang.go
+++ b/loader/libclang.go
@@ -20,7 +20,7 @@ import "C"
 
 var globalFileInfo *fileInfo
 
-func (info *fileInfo) parseFragment(fragment string) error {
+func (info *fileInfo) parseFragment(fragment string, cflags []string) error {
 	index := C.clang_createIndex(0, 1)
 	defer C.clang_disposeIndex(index)
 
@@ -36,11 +36,21 @@ func (info *fileInfo) parseFragment(fragment string) error {
 		Contents: fragmentC,
 	}
 
+	// convert Go slice of strings to C array of strings.
+	cmdargsC := C.malloc(C.size_t(len(cflags)) * C.size_t(unsafe.Sizeof(uintptr(0))))
+	defer C.free(cmdargsC)
+	cmdargs := (*[1<<30 - 1]*C.char)(cmdargsC)
+	for i, cflag := range cflags {
+		s := C.CString(cflag)
+		cmdargs[i] = s
+		defer C.free(unsafe.Pointer(s))
+	}
+
 	var unit C.CXTranslationUnit
 	errCode := C.clang_parseTranslationUnit2(
 		index,
 		filenameC,
-		(**C.char)(unsafe.Pointer(uintptr(0))), 0, // command line args
+		(**C.char)(cmdargsC), C.int(len(cflags)), // command line args
 		&unsavedFile, 1, // unsaved files
 		C.CXTranslationUnit_None,
 		&unit)
diff --git a/loader/loader.go b/loader/loader.go
index c67ad39e..7c888757 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -20,6 +20,7 @@ type Program struct {
 	fset        *token.FileSet
 	TypeChecker types.Config
 	Dir         string // current working directory (for error reporting)
+	CFlags      []string
 }
 
 // Package holds a loaded package, its imports, and its parsed files.
@@ -290,7 +291,7 @@ func (p *Package) parseFiles() ([]*ast.File, error) {
 			fileErrs = append(fileErrs, err)
 			continue
 		}
-		err = p.processCgo(path, f)
+		err = p.processCgo(path, f, append(p.CFlags, "-I"+p.Package.Dir))
 		if err != nil {
 			fileErrs = append(fileErrs, err)
 			continue
diff --git a/main.go b/main.go
index 1bcd01c4..c1a311f2 100644
--- a/main.go
+++ b/main.go
@@ -44,6 +44,7 @@ func Compile(pkgName, outpath string, spec *TargetSpec, config *BuildConfig, act
 	compilerConfig := compiler.Config{
 		Triple:     spec.Triple,
 		GC:         config.gc,
+		CFlags:     spec.CFlags,
 		Debug:      config.debug,
 		DumpSSA:    config.dumpSSA,
 		RootDir:    sourceDir(),
diff --git a/testdata/cgo/main.c b/testdata/cgo/main.c
index ecee9317..b0d4ba56 100644
--- a/testdata/cgo/main.c
+++ b/testdata/cgo/main.c
@@ -1,3 +1,5 @@
+#include "main.h"
+
 int fortytwo() {
 	return 42;
 }
diff --git a/testdata/cgo/main.go b/testdata/cgo/main.go
index f4a5d4d8..b8903a7d 100644
--- a/testdata/cgo/main.go
+++ b/testdata/cgo/main.go
@@ -2,8 +2,7 @@ package main
 
 /*
 int fortytwo(void);
-typedef short myint;
-int add(int a, int b);
+#include "main.h"
 */
 import "C"
 
diff --git a/testdata/cgo/main.h b/testdata/cgo/main.h
new file mode 100644
index 00000000..f41711f4
--- /dev/null
+++ b/testdata/cgo/main.h
@@ -0,0 +1,2 @@
+typedef short myint;
+int add(int a, int b);