Add attribute @(no_sanitize_address)

The purposes of this attribute is to let procedures opt-out of being
instrumented with asan. Typically an allocator that includes 'in-band'
meta-data will be accessing poisoned values (such as tlsf).

Making asan work with these allocators becomes very challenging so
just being to ignore asan within specific allocator procedures
makes it easier to reason and removes the need to temporarily
poison and unpoison allocator data.

src/check_decl.cpp

@@ -1229,6 +1229,7 @@ gb_internal void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 
 	e->Procedure.has_instrumentation = has_instrumentation;
 
+	e->Procedure.no_sanitize_address = ac.no_sanitize_address;
 
 	e->deprecated_message = ac.deprecated_message;
 	e->warning_message = ac.warning_message;

src/checker.cpp

@@ -3711,6 +3711,12 @@ gb_internal DECL_ATTRIBUTE_PROC(proc_decl_attribute) {
 		}
 		ac->instrumentation_exit = true;
 		return true;
+	} else if (name == "no_sanitize_address") {
+		if (value != nullptr) {
+			error(value, "'%.*s' expects no parameter", LIT(name));
+		}
+		ac->no_sanitize_address = true;
+		return true;
 	}
 	return false;
 }

src/checker.hpp

@@ -139,6 +139,7 @@ struct AttributeContext {
 	bool    entry_point_only      : 1;
 	bool    instrumentation_enter : 1;
 	bool    instrumentation_exit  : 1;
+	bool    no_sanitize_address   : 1;
 	bool    rodata                : 1;
 	bool    ignore_duplicates     : 1;
 	u32 optimization_mode; // ProcedureOptimizationMode
@@ -629,4 +630,4 @@ gb_internal void add_untyped_expressions(CheckerInfo *cinfo, UntypedExprInfoMap
 gb_internal GenTypesData *ensure_polymorphic_record_entity_has_gen_types(CheckerContext *ctx, Type *original_type);
 
 
-gb_internal void init_map_internal_types(Type *type);
+gb_internal void init_map_internal_types(Type *type);

src/entity.cpp

@@ -258,6 +258,7 @@ struct Entity {
 			bool    is_memcpy_like             : 1;
 			bool    uses_branch_location       : 1;
 			bool    is_anonymous               : 1;
+			bool    no_sanitize_address        : 1;
 		} Procedure;
 		struct {
 			Array<Entity *> entities;

src/llvm_backend_proc.cpp

@@ -333,7 +333,7 @@ gb_internal lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool i
 	}
 
 	if (p->body && entity->pkg && ((entity->pkg->kind == Package_Normal) || (entity->pkg->kind == Package_Init))) {
-		if (build_context.sanitizer_flags & SanitizerFlag_Address) {
+		if (build_context.sanitizer_flags & SanitizerFlag_Address && !entity->Procedure.no_sanitize_address) {
 			lb_add_attribute_to_proc(m, p->value, "sanitize_address");
 		}
 		if (build_context.sanitizer_flags & SanitizerFlag_Memory) {