Minimize memory usage by having an arena per thread rather than an arena per file

src/array.cpp

@@ -89,7 +89,9 @@ template <typename T>
 void slice_init(Slice<T> *s, gbAllocator const &allocator, isize count) {
 	GB_ASSERT(count >= 0);
 	s->data = gb_alloc_array(allocator, T, count);
-	GB_ASSERT(s->data != nullptr);
+	if (count > 0) {
+		GB_ASSERT(s->data != nullptr);
+	}
 	s->count = count;
 }
 

src/checker.cpp

@@ -225,8 +225,8 @@ bool decl_info_has_init(DeclInfo *d) {
 Scope *create_scope(CheckerInfo *info, Scope *parent, isize init_elements_capacity=DEFAULT_SCOPE_CAPACITY) {
 	Scope *s = gb_alloc_item(permanent_allocator(), Scope);
 	s->parent = parent;
-	string_map_init(&s->elements, permanent_allocator(), init_elements_capacity);
-	ptr_set_init(&s->imported, permanent_allocator(), 0);
+	string_map_init(&s->elements, heap_allocator(), init_elements_capacity);
+	ptr_set_init(&s->imported, heap_allocator(), 0);
 	mutex_init(&s->mutex);
 
 	if (parent != nullptr && parent != builtin_pkg->scope) {

src/common.cpp

@@ -1021,7 +1021,7 @@ LoadedFileError load_file_32(char const *fullpath, LoadedFile *memory_mapped_fil
 	#endif
 	}
 	
-	gbFileContents fc = gb_file_read_contents(heap_allocator(), true, fullpath);
+	gbFileContents fc = gb_file_read_contents(permanent_allocator(), true, fullpath);
 
 	if (fc.size > I32_MAX) {
 		err = LoadedFile_FileTooLarge;

src/main.cpp

@@ -2577,7 +2577,7 @@ int main(int arg_count, char const **arg_ptr) {
 	// NOTE(bill): add 'shared' directory if it is not already set
 	if (!find_library_collection_path(str_lit("shared"), nullptr)) {
 		add_library_collection(str_lit("shared"),
-							   get_fullpath_relative(heap_allocator(), odin_root_dir(), str_lit("shared")));
+			get_fullpath_relative(heap_allocator(), odin_root_dir(), str_lit("shared")));
 	}
 
 

src/parser.cpp

@@ -57,6 +57,9 @@ isize ast_node_size(AstKind kind) {
 	return align_formula_isize(gb_size_of(AstCommonStuff) + ast_variant_sizes[kind], gb_align_of(void *));
 
 }
+
+gb_global std::atomic<isize> global_total_node_memory_allocated;
+
 // NOTE(bill): And this below is why is I/we need a new language! Discriminated unions are a pain in C/C++
 Ast *alloc_ast_node(AstFile *f, AstKind kind) {
 	gbAllocator a = ast_allocator(f);
@@ -66,6 +69,9 @@ Ast *alloc_ast_node(AstFile *f, AstKind kind) {
 	Ast *node = cast(Ast *)gb_alloc(a, size);
 	node->kind = kind;
 	node->file_id = f ? f->id : 0;
+
+	global_total_node_memory_allocated += size;
+
 	return node;
 }
 
@@ -4851,12 +4857,6 @@ ParseFileError init_ast_file(AstFile *f, String fullpath, TokenPos *err_pos) {
 	f->prev_token = f->tokens[f->prev_token_index];
 	f->curr_token = f->tokens[f->curr_token_index];
 
-	isize const page_size = 4*1024;
-	isize block_size = 2*f->tokens.count*gb_size_of(Ast);
-	block_size = ((block_size + page_size-1)/page_size) * page_size;
-	block_size = gb_clamp(block_size, page_size, DEFAULT_MINIMUM_BLOCK_SIZE);
-	f->arena.minimum_block_size = block_size;
-
 	array_init(&f->comments, heap_allocator(), 0, 0);
 	array_init(&f->imports,  heap_allocator(), 0, 0);
 

src/parser.hpp

@@ -97,8 +97,6 @@ struct AstFile {
 	AstPackage * pkg;
 	Scope *      scope;
 
-	Arena  arena;
-
 	Ast *        pkg_decl;
 	String       fullpath;
 	Tokenizer    tokenizer;
@@ -801,10 +799,10 @@ gb_inline bool is_ast_when_stmt(Ast *node) {
 	return node->kind == Ast_WhenStmt;
 }
 
-gb_global gb_thread_local Arena global_ast_arena = {};
+gb_global gb_thread_local Arena global_thread_local_ast_arena = {};
 
 gbAllocator ast_allocator(AstFile *f) {
-	Arena *arena = f ? &f->arena : &global_ast_arena;
+	Arena *arena = &global_thread_local_ast_arena;
 	return arena_allocator(arena);
 }