From 79c0f7dfb063b5d29dc4547d37efbcb86a89fdac Mon Sep 17 00:00:00 2001
From: Aqua-sama <aqua@iserlohn-fortress.net>
Date: Sun, 21 Feb 2021 13:39:12 +0200
Subject: Call global constructors

---
 drivers/cga.cc     |  4 +++-
 drivers/cga.h      |  6 +++---
 libk/stdlib.h      |  1 -
 linker.ld          |  4 ++++
 src/boot.s         |  3 +++
 src/kernel.cc      | 18 ++++++++++++++----
 toolchain.makefile |  6 +++---
 7 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/cga.cc b/drivers/cga.cc
index 961d7e4..0646ff7 100644
--- a/drivers/cga.cc
+++ b/drivers/cga.cc
@@ -22,7 +22,9 @@ constexpr uint8_t cursor_addr_l = 15;  // 0xf
  */
 constexpr uint8_t cursor_hide = 0b00100000;
 
-CGA::CGA(Colour fg, Colour bg, uint32_t address) : colour_fg(fg), colour_bg(bg) {
+constexpr uint32_t address = 0xB8000;
+
+CGA::CGA() {
   buffer = reinterpret_cast<Entry*>(address);
 
   // clear buffer
diff --git a/drivers/cga.h b/drivers/cga.h
index f0ca412..f4dfb3c 100644
--- a/drivers/cga.h
+++ b/drivers/cga.h
@@ -35,7 +35,7 @@ public:
     CGA_COLOR_WHITE = 15,
   };
 
-  CGA(Colour fg = CGA_COLOR_BLACK, Colour bg = CGA_COLOR_LIGHT_GREY, uint32_t address = 0xB8000);
+  CGA();
   ~CGA() = default;
 
   void set_colour(Colour fg, Colour bg);
@@ -58,8 +58,8 @@ private:
   const size_t max_columns = 80, max_rows = 25;
   size_t column = 0, row = 0;
 
-  Colour colour_fg;
-  Colour colour_bg;
+  Colour colour_fg = CGA_COLOR_BLACK;
+  Colour colour_bg = CGA_COLOR_LIGHT_GREY;
 
   Entry* buffer;
 
diff --git a/libk/stdlib.h b/libk/stdlib.h
index 7213384..843cc14 100644
--- a/libk/stdlib.h
+++ b/libk/stdlib.h
@@ -21,7 +21,6 @@ private:
 
 class Console {
 public:
-  virtual ~Console() = default;
   virtual void write(char c) = 0;
   virtual void write(ViewIterator& msg) = 0;
   virtual void update_cursor() = 0;
diff --git a/linker.ld b/linker.ld
index c6c706e..eaf118c 100644
--- a/linker.ld
+++ b/linker.ld
@@ -27,6 +27,10 @@ SECTIONS
 	/* Read-write data (initialized) */
 	.data :
 	{
+            start_ctors = .;
+            KEEP(*(.init_array));
+            KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*)));
+            end_ctors = .;
 		*(.data)
 	}
  
diff --git a/src/boot.s b/src/boot.s
index bb446d8..2286152 100644
--- a/src/boot.s
+++ b/src/boot.s
@@ -41,6 +41,8 @@ stack_top:
     bootloader will jump to this position once the kernel has been loaded.
 */
 .section .text
+.extern kernel_constructors
+.extern kernel_main
 .global _start
 .type _start, @function
 _start:
@@ -59,6 +61,7 @@ _start:
 
         pushl %ebx      # push the pointer to the multiboot structure
         pushl %eax      # push the multiboot magic value
+        call kernel_constructors
 
 	/*
 	Enter the high-level kernel. The ABI requires the stack is 16-byte
diff --git a/src/kernel.cc b/src/kernel.cc
index 7aaaa37..37773e1 100644
--- a/src/kernel.cc
+++ b/src/kernel.cc
@@ -15,16 +15,26 @@
 #include "idt.h"
 #include "serial.h"
 
+SerialPort serial0;
+CGA video0;
+
+typedef void (*constructor)();
+
 extern "C" {
+
+constructor start_ctors;
+constructor end_ctors;
+void kernel_constructors() {
+  for (constructor* i = &start_ctors; i != &end_ctors; ++i) (*i)();
+}
+
 void dump_multiboot(uint32_t mb_magic, uint32_t mb_addr);
 void dump_gdt();
 
 void kernel_main([[maybe_unused]] uint32_t mb_magic, [[maybe_unused]] uint32_t mb_addr) {
-  SerialPort s0;
-  if (s0.self_check()) Console::set(&s0);
+  if (serial0.self_check()) Console::set(&serial0);
 
-  CGA terminal;
-  Console::set(&terminal);
+  Console::set(&video0);
 
   printk("Hello, kernel World!\n");
 
diff --git a/toolchain.makefile b/toolchain.makefile
index aa64c5b..ee9cc0e 100644
--- a/toolchain.makefile
+++ b/toolchain.makefile
@@ -8,11 +8,11 @@ LD       := ld.lld
 LD_FLAGS := -T linker.ld
 
 CXX         := clang++
-CXX_FLAGS   := -std=c++20 -ffreestanding -nostdlib -nostdinc -nostdinc++ \
-               -fno-exceptions -fno-rtti -Wall -Wextra -Werror=pedantic -O2 \
+CXX_FLAGS   := -std=c++20 \
+	       -mkernel -ffreestanding -nostdlib -nostdinc -nostdinc++ \
+               -Wall -Wextra -Werror=pedantic -O2 \
 	       -Werror=date-time \
 	       -Werror=shadow-all \
-	       -Wnon-virtual-dtor \
 	       -Wold-style-cast -Wconversion \
 	       -Wconsumed
 CXX_INCLUDE := $(CURDIR)/libk $(CURDIR)/drivers
-- 
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