From 24fce21d9055ac4cd2124c0fe5396f430e99f24f Mon Sep 17 00:00:00 2001
From: gingerBill <bill@gingerbill.org>
Date: Wed, 28 Apr 2021 10:49:30 +0100
Subject: [PATCH] Add "naked" calling convention (removes prologue and
 epilogue)

---
 core/runtime/core.odin | 1 +
 src/docs_writer.cpp    | 3 +++
 src/llvm_backend.cpp   | 4 ++++
 src/llvm_backend.hpp   | 1 +
 src/parser.cpp         | 1 +
 src/parser.hpp         | 3 ++-
 src/types.cpp          | 3 +++
 7 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/core/runtime/core.odin b/core/runtime/core.odin
index 0033aad9a..5f016579f 100644
--- a/core/runtime/core.odin
+++ b/core/runtime/core.odin
@@ -32,6 +32,7 @@ Calling_Convention :: enum u8 {
 	Fast_Call   = 5,
 
 	None        = 6,
+	Naked       = 7,
 }
 
 Type_Info_Enum_Value :: distinct i64;
diff --git a/src/docs_writer.cpp b/src/docs_writer.cpp
index f4fd02376..03ea25930 100644
--- a/src/docs_writer.cpp
+++ b/src/docs_writer.cpp
@@ -697,6 +697,9 @@ OdinDocTypeIndex odin_doc_type(OdinDocWriter *w, Type *type) {
 			case ProcCC_None:
 				calling_convention = str_lit("none");
 				break;
+			case ProcCC_Naked:
+				calling_convention = str_lit("naked");
+				break;
 			case ProcCC_InlineAsm:
 				calling_convention = str_lit("inline-assembly");
 				break;
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index 74d5bbe01..f81077b47 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -2588,6 +2588,10 @@ lbProcedure *lb_create_procedure(lbModule *m, Entity *entity) {
 		lb_add_attribute_to_proc(m, p->value, "noreturn");
 	}
 
+	if (pt->Proc.calling_convention == ProcCC_Naked) {
+		lb_add_attribute_to_proc(m, p->value, "naked");
+	}
+
 	switch (p->inlining) {
 	case ProcInlining_inline:
 		lb_add_attribute_to_proc(m, p->value, "alwaysinline");
diff --git a/src/llvm_backend.hpp b/src/llvm_backend.hpp
index e8811a91e..cd6a99c20 100644
--- a/src/llvm_backend.hpp
+++ b/src/llvm_backend.hpp
@@ -472,6 +472,7 @@ lbCallingConventionKind const lb_calling_convention_map[ProcCC_MAX] = {
 	lbCallingConvention_X86_FastCall, // ProcCC_FastCall,
 
 	lbCallingConvention_C,            // ProcCC_None,
+	lbCallingConvention_C,            // ProcCC_Naked,
 	lbCallingConvention_C,            // ProcCC_InlineAsm,
 };
 
diff --git a/src/parser.cpp b/src/parser.cpp
index a7e4c9162..a6764de08 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -3220,6 +3220,7 @@ ProcCallingConvention string_to_calling_convention(String s) {
 	if (s == "fastcall")    return ProcCC_FastCall;
 	if (s == "fast")        return ProcCC_FastCall;
 	if (s == "none")        return ProcCC_None;
+	if (s == "naked")       return ProcCC_Naked;
 	return ProcCC_Invalid;
 }
 
diff --git a/src/parser.hpp b/src/parser.hpp
index 8c2eadb46..93c0363ab 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -215,8 +215,9 @@ enum ProcCallingConvention {
 	ProcCC_FastCall = 5,
 
 	ProcCC_None = 6,
+	ProcCC_Naked = 7,
 
-	ProcCC_InlineAsm = 7,
+	ProcCC_InlineAsm = 8,
 
 	ProcCC_MAX,
 
diff --git a/src/types.cpp b/src/types.cpp
index 56081acc8..7b5b81c43 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -3618,6 +3618,9 @@ gbString write_type_to_string(gbString str, Type *type) {
 		case ProcCC_None:
 			str = gb_string_appendc(str, " \"none\" ");
 			break;
+		case ProcCC_Naked:
+			str = gb_string_appendc(str, " \"naked\" ");
+			break;
 		// case ProcCC_VectorCall:
 		// 	str = gb_string_appendc(str, " \"vectorcall\" ");
 		// 	break;