From a8db9b0b089ce245158400e64c4ba4247a009223 Mon Sep 17 00:00:00 2001
From: Dmitry Dubrovin <dmitry@dubrovin.dev>
Date: Tue, 24 Jan 2023 00:26:33 +0300
Subject: [PATCH 1/4] Add llvm build support

---
 Makefile  | 20 ++++++++++++++++++--
 script.ld | 24 ++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100644 script.ld

diff --git a/Makefile b/Makefile
index 4c8b27a..322c4e8 100644
--- a/Makefile
+++ b/Makefile
@@ -10,6 +10,16 @@ endif
 CFLAGS = -fno-pic -ffreestanding -static -fno-builtin -fno-strict-aliasing \
 		 -Wall -ggdb -m32 -Werror -fno-omit-frame-pointer
 CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
+ASMFLAGS = -m32 -ffreestanding -c -g
+
+ifeq ($(LLVM),on)
+#AS=llvm-as
+LD=ld.lld
+CC=clang
+CFLAGS += -target elf-i386
+ASMFLAGS = -target elf-i386 -ffreestanding -c -g
+LDKERNELFLAGS = --script=script.ld
+endif
 
 run: image.bin
 	qemu-system-i386 -drive format=raw,file=$< -serial mon:stdio
@@ -41,6 +51,12 @@ debug-boot: image.bin mbr.elf
 		-ex "break *0x7c00" \
 		-ex "continue"
 
+debug-server: image.bin
+	qemu-system-i386 -drive format=raw,file=$< -s -S
+
+debug-server-nox: image.bin
+	qemu-system-i386 -nographic -drive format=raw,file=$< -s -S
+
 debug: image.bin
 	qemu-system-i386 -drive format=raw,file=$< -s -S &
 	$(GDB) kernel.bin \
@@ -67,13 +83,13 @@ image.bin: mbr.bin fs.img
 	cat $^ >$@
 
 kernel.bin: kernel.o console.o drivers/vga.o drivers/uart.o
-	$(LD) $(LDFLAGS) -o $@ -Ttext 0x1000 $^
+	$(LD) $(LDFLAGS) $(LDKERNELFLAGS) -o $@ -Ttext 0x1000 $^
 
 %.o: %.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
 %.o: %.S
-	$(CC) -m32 -ffreestanding -c -g $^ -o $@
+	$(CC) $(ASMFLAGS) $^ -o $@
 
 mbr.bin: mbr.o
 	$(LD) -m elf_i386 -Ttext=0x7c00 --oformat=binary $^ -o $@
diff --git a/script.ld b/script.ld
new file mode 100644
index 0000000..e8c80c1
--- /dev/null
+++ b/script.ld
@@ -0,0 +1,24 @@
+SECTIONS
+{
+.text (0x1000) : {
+ startup.o( .text )
+}
+
+.data : ALIGN(CONSTANT(MAXPAGESIZE)) {
+_DATA_START_ = .;
+ *(.data)
+_DATA_END_ = .;
+}
+
+.rodata : ALIGN(CONSTANT(MAXPAGESIZE)) {
+_RODATA_START_ = .;
+ *(.rodata)
+_RODATA_START_ = .;
+}
+
+.bss : ALIGN(CONSTANT(MAXPAGESIZE)) {
+_BSS_START_ = .;
+ *(.bss)
+_BSS_END_ = .;
+}
+}
\ No newline at end of file

From 453cd6ce504e66e147d64b49f981faa83922bfe9 Mon Sep 17 00:00:00 2001
From: Dmitry Dubrovin <dmitry@dubrovin.dev>
Date: Tue, 24 Jan 2023 00:46:08 +0300
Subject: [PATCH 2/4] Improve Readme.md

---
 README.md | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 4422fad..c4998de 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,25 @@
-Yet Another BootLoader, OS Kernel and Other stuff
+# Yet Another BootLoader, OS Kernel and Other stuff
 
-Quickstart:
+## Quickstart:
 ```
 $ ./setup.sh
 $ make
 ```
+## How to run using llvm
 
-Includes code from:
+You can use this way even if you have windows. You need to install llvm and qemu. 
+Check that executables `clang`, `ld.lld`, `qemu-system-i386` available from your terminal/console.
+
+```
+make LLVM=on
+```
+
+## How to debug in my favorite IDE
+
+Start debug server using command `make debug-server` or `make debug-server-nox` if you don't want to see gui, and 
+then connect using remote gdb option to localhost:1234 (symbols file is kernel.bin)
+
+## Includes code from:
 * https://github.com/mit-pdos/xv6-public
 * https://github.com/FRosner/FrOS
 * https://github.com/dhavalhirdhav/LearnOS

From 93a30be4f5a1ac4d22d7b83e2959c3015eeaadeb Mon Sep 17 00:00:00 2001
From: Alexander Myltsev <a.myltsev@gmail.com>
Date: Tue, 24 Jan 2023 02:13:56 +0400
Subject: [PATCH 3/4] Create build.yml.

---
 .github/workflows/build.yml | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 .github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..e7779ef
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,17 @@
+name: CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: build disk image
+      run: make image.bin

From 976987e0755cddf56e207804e596427e28dbaa7b Mon Sep 17 00:00:00 2001
From: Dmitry Dubrovin <dmitry@dubrovin.dev>
Date: Tue, 24 Jan 2023 14:15:25 +0300
Subject: [PATCH 4/4] Fixes

---
 script.ld | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/script.ld b/script.ld
index e8c80c1..9147a8b 100644
--- a/script.ld
+++ b/script.ld
@@ -1,7 +1,13 @@
 SECTIONS
 {
 .text (0x1000) : {
- startup.o( .text )
+ *( .text )
+}
+
+.rodata : {
+_RODATA_START_ = .;
+ *(.rodata)
+_RODATA_START_ = .;
 }
 
 .data : ALIGN(CONSTANT(MAXPAGESIZE)) {
@@ -10,15 +16,10 @@ _DATA_START_ = .;
 _DATA_END_ = .;
 }
 
-.rodata : ALIGN(CONSTANT(MAXPAGESIZE)) {
-_RODATA_START_ = .;
- *(.rodata)
-_RODATA_START_ = .;
-}
 
 .bss : ALIGN(CONSTANT(MAXPAGESIZE)) {
 _BSS_START_ = .;
  *(.bss)
 _BSS_END_ = .;
 }
-}
\ No newline at end of file
+}