codegen for coro_begin instruction

See #727

Author: andrewrk

src/all_types.hpp

@@ -1613,6 +1613,7 @@ struct CodeGen {
     LLVMValueRef coro_id_fn_val;
     LLVMValueRef coro_alloc_fn_val;
     LLVMValueRef coro_size_fn_val;
+    LLVMValueRef coro_begin_fn_val;
     bool error_during_imports;
 
     const char **clang_argv;

src/codegen.cpp

@@ -987,6 +987,22 @@ static LLVMValueRef get_coro_size_fn_val(CodeGen *g) {
     return g->coro_size_fn_val;
 }
 
+static LLVMValueRef get_coro_begin_fn_val(CodeGen *g) {
+    if (g->coro_begin_fn_val)
+        return g->coro_begin_fn_val;
+
+    LLVMTypeRef param_types[] = {
+        ZigLLVMTokenTypeInContext(LLVMGetGlobalContext()),
+        LLVMPointerType(LLVMInt8Type(), 0),
+    };
+    LLVMTypeRef fn_type = LLVMFunctionType(LLVMPointerType(LLVMInt8Type(), 0), param_types, 2, false);
+    Buf *name = buf_sprintf("llvm.coro.begin");
+    g->coro_begin_fn_val = LLVMAddFunction(g->module, buf_ptr(name), fn_type);
+    assert(LLVMGetIntrinsicID(g->coro_begin_fn_val));
+
+    return g->coro_begin_fn_val;
+}
+
 static LLVMValueRef get_return_address_fn_val(CodeGen *g) {
     if (g->return_address_fn_val)
         return g->return_address_fn_val;
@@ -3808,7 +3824,13 @@ static LLVMValueRef ir_render_coro_size(CodeGen *g, IrExecutable *executable, Ir
 }
 
 static LLVMValueRef ir_render_coro_begin(CodeGen *g, IrExecutable *executable, IrInstructionCoroBegin *instruction) {
-    zig_panic("TODO ir_render_coro_begin");
+    LLVMValueRef coro_id = ir_llvm_value(g, instruction->coro_id);
+    LLVMValueRef coro_mem_ptr = ir_llvm_value(g, instruction->coro_mem_ptr);
+    LLVMValueRef params[] = {
+        coro_id,
+        coro_mem_ptr,
+    };
+    return LLVMBuildCall(g->builder, get_coro_begin_fn_val(g), params, 2, "");
 }
 
 static LLVMValueRef ir_render_coro_alloc_fail(CodeGen *g, IrExecutable *executable,