From db66039dfe6a813e647c4044211890385fc47664 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Fri, 20 Apr 2018 23:59:55 +0200
Subject: [PATCH] Implement panic()

---
 src/runtime/runtime.go | 17 +++++++++++++++++
 tgo.go                 | 12 ++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
index c891641c..944325e7 100644
--- a/src/runtime/runtime.go
+++ b/src/runtime/runtime.go
@@ -2,6 +2,7 @@
 package runtime
 
 // #include <stdio.h>
+// #include <stdlib.h>
 import "C"
 
 const Compiler = "tgo"
@@ -39,3 +40,19 @@ func printspace() {
 func printnl() {
 	C.putchar('\n')
 }
+
+func printitf(msg interface{}) {
+	switch msg := msg.(type) {
+	case string:
+		print(msg)
+	default:
+		print("???")
+	}
+}
+
+func _panic(message interface{}) {
+	printstring("panic: ")
+	printitf(message)
+	printnl()
+	C.exit(1)
+}
diff --git a/tgo.go b/tgo.go
index ab53ab5d..c2a615e2 100644
--- a/tgo.go
+++ b/tgo.go
@@ -43,6 +43,7 @@ type Compiler struct {
 	stringType      llvm.Type
 	interfaceType   llvm.Type
 	typeassertType  llvm.Type
+	panicFunc       llvm.Value
 	printstringFunc llvm.Value
 	printintFunc    llvm.Value
 	printbyteFunc   llvm.Value
@@ -97,6 +98,9 @@ func NewCompiler(pkgName, triple string) (*Compiler, error) {
 	// Go typeassert result: tuple of (ptr, bool)
 	c.typeassertType = llvm.StructType([]llvm.Type{llvm.PointerType(llvm.Int8Type(), 0), llvm.Int1Type()}, false)
 
+	panicType := llvm.FunctionType(llvm.VoidType(), []llvm.Type{c.interfaceType}, false)
+	c.panicFunc = llvm.AddFunction(c.mod, "runtime._panic", panicType)
+
 	printstringType := llvm.FunctionType(llvm.VoidType(), []llvm.Type{c.stringType}, false)
 	c.printstringFunc = llvm.AddFunction(c.mod, "runtime.printstring", printstringType)
 	printintType := llvm.FunctionType(llvm.VoidType(), []llvm.Type{c.intType}, false)
@@ -434,6 +438,14 @@ func (c *Compiler) parseInstr(frame *Frame, instr ssa.Instruction) error {
 		blockJump := frame.blocks[instr.Block().Succs[0]]
 		c.builder.CreateBr(blockJump)
 		return nil
+	case *ssa.Panic:
+		value, err := c.parseExpr(frame, instr.X)
+		if err != nil {
+			return err
+		}
+		c.builder.CreateCall(c.panicFunc, []llvm.Value{value}, "")
+		c.builder.CreateUnreachable()
+		return nil
 	case *ssa.Return:
 		if len(instr.Results) == 0 {
 			c.builder.CreateRetVoid()