Make clangd work with toolchain's headers

.clangd.template

@@ -0,0 +1,9 @@
+CompileFlags:
+  Compiler: i686-elf-gcc
+  Add:
+    - "-target"
+    - "i686-elf"
+    - "-ffreestanding"
+    - "-nostdlibinc"
+    - "-isystem"
+    - "${env:I686_ELF_GCC_INCLUDE}"

.gitignore

@@ -139,4 +139,5 @@ dkms.conf
 
 build/
 nob
-nob.old
+nob.old
+.clangd

nob.c

@@ -1,9 +1,66 @@
 #define NOB_IMPLEMENTATION
 #include "nob.h"
+#include <stdbool.h>
 
 #define BUILD_FOLDER "build/"
 #define SRC_FOLDER "src/"
 
+bool render_clangd_config(void) {
+    Nob_String_Builder tmpl = {0};
+    if (!nob_read_entire_file(".clangd.template", &tmpl))
+        return false;
+    nob_sb_append_null(&tmpl);
+
+    const char *include_path = getenv("I686_ELF_GCC_INCLUDE");
+    if (include_path == NULL) {
+        nob_log(NOB_ERROR, "I686_ELF_GCC_INCLUDE not set");
+        nob_sb_free(tmpl);
+        return false;
+    }
+
+    const char *needle = "${env:I686_ELF_GCC_INCLUDE}";
+    Nob_String_Builder out = {0};
+
+    const char *cursor = tmpl.items;
+    const char *found;
+    while ((found = strstr(cursor, needle)) != NULL) {
+        nob_sb_append_buf(&out, cursor, found - cursor);
+        nob_sb_append_cstr(&out, include_path);
+        cursor = found + strlen(needle);
+    }
+    nob_sb_append_cstr(&out, cursor);
+
+    bool ok = nob_write_entire_file(".clangd", out.items, out.count);
+
+    nob_sb_free(tmpl);
+    nob_sb_free(out);
+    return ok;
+}
+
+bool build_assembly(Nob_Cmd *cmd) {
+    nob_cmd_append(cmd, "i686-elf-as", "-o", BUILD_FOLDER "boot.o", SRC_FOLDER "boot.s");
+    if (!nob_cmd_run(cmd))
+        return false;
+
+    return true;
+}
+
+bool build_c(Nob_Cmd *cmd) {
+    nob_cmd_append(cmd,
+                   "i686-elf-gcc",
+                   "-std=gnu99",
+                   "-ffreestanding",
+                   "-Wall",
+                   "-Wextra",
+                   "-O2",
+                   "-o", BUILD_FOLDER "kernel.o",
+                   "-c", SRC_FOLDER "kernel.c");
+    if (!nob_cmd_run(cmd))
+        return false;
+
+    return true;
+}
+
 int main(int argc, char **argv) {
     NOB_GO_REBUILD_URSELF(argc, argv);
 
@@ -12,12 +69,11 @@ int main(int argc, char **argv) {
 
     Nob_Cmd cmd = {0};
 
-    nob_cmd_append(&cmd, "i686-elf-as", "-o", BUILD_FOLDER "boot.o", SRC_FOLDER "boot.s");
-    if (!nob_cmd_run(&cmd))
+    if (!render_clangd_config())
         return 1;
-
-    nob_cmd_append(&cmd, "i686-elf-gcc", "-Wall", "-Wextra", "-o", BUILD_FOLDER "kernel", SRC_FOLDER "kernel.c");
-    if (!nob_cmd_run(&cmd))
+    if (!build_assembly(&cmd))
+        return 1;
+    if (!build_c(&cmd))
         return 1;
 
     return 0;

shell.nix

@@ -7,4 +7,8 @@ pkgs.mkShell {
       pkgsCross.i686-embedded.buildPackages.binutils
       gdb
     ];
+
+  shellHook = ''
+    export I686_ELF_GCC_INCLUDE="${pkgs.pkgsCross.i686-embedded.buildPackages.gcc.cc}/lib/gcc/i686-elf/${pkgs.pkgsCross.i686-embedded.buildPackages.gcc.version}/include"
+  '';
 }

src/kernel.c

@@ -1,6 +1,16 @@
-#include "stdio.h"
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#if defined(__linux__)
+#error "Not using a cross compiler"
+#endif
+
+#if !defined(__i386__)
+#error "Not using the right compiler"
+#endif
 
 int main() {
-    printf("Hello, world!\n");
-    return 0;
+    return 1;
+    return false;
 }