compiler: Implement init()

src/runtime/runtime.c

@@ -2,9 +2,11 @@
 #include "runtime.h"
 #include <string.h>
 
+void go_init() __asm__("runtime.initAll");
 void go_main() __asm__("main.main");
 
 int main() {
+	go_init();
 	go_main();
 
 	return 0;

src/runtime/runtime_nrf.c

@@ -18,7 +18,6 @@ void uart_send(uint8_t c) {
 }
 
 void _start() {
-	uart_init(6); // pin_tx = 6, for NRF52840-DK
 	main();
 }
 

src/runtime/runtime_nrf.go

@@ -6,6 +6,10 @@ package runtime
 // #include "runtime_nrf.h"
 import "C"
 
+func init() {
+	C.uart_init(6) // pin_tx = 6, for NRF52840-DK
+}
+
 const Microsecond = 1
 
 func putchar(c byte) {

tgo.go

@@ -55,6 +55,7 @@ type Compiler struct {
 	memsetIntrinsic llvm.Value
 	itfTypeNumbers  map[types.Type]uint64
 	itfTypes        []types.Type
+	initFuncs       []llvm.Value
 }
 
 type Frame struct {
@@ -212,6 +213,17 @@ func (c *Compiler) Parse(mainPath string, buildTags []string) error {
 		c.parsePackage(program, pkg)
 	}
 
+	// After all packages are imported, add a synthetic initializer function
+	// that calls the initializer of each package.
+	initType := llvm.FunctionType(llvm.VoidType(), nil, false)
+	initFn := llvm.AddFunction(c.mod, "runtime.initAll", initType)
+	block := c.ctx.AddBasicBlock(initFn, "entry")
+	c.builder.SetInsertPointAtEnd(block)
+	for _, fn := range c.initFuncs {
+		c.builder.CreateCall(fn, nil, "")
+	}
+	c.builder.CreateRetVoid()
+
 	return nil
 }
 
@@ -434,7 +446,7 @@ func (c *Compiler) parseFuncDecl(f *ssa.Function) (*Frame, error) {
 }
 
 func (c *Compiler) parseFunc(frame *Frame, f *ssa.Function) error {
-	if frame.llvmFn.Name() != "main.main" {
+	if frame.llvmFn.Name() != "main.main" && frame.llvmFn.Name() != "runtime.init" {
 		// This function is only used from within Go.
 		frame.llvmFn.SetLinkage(llvm.PrivateLinkage)
 	}