#include <stdlib.h>
#include <string.h>
+/* Some terminology used in function names:
+ * - initialize: These functions take a pointer and potentially some other arguments, and use those
+ * to initialize the value pointed to by self. Initialize functions DO NOT allocate the function,
+ * so they can be used to initialize stack-allocated variables.
+ * - construct: This allocates a value for a pointer, initializes it, and returns it. This is for
+ * heap-allocated values. It may be as simple as allocating the memory, calling an initialize, and
+ * returning it.
+ * - deinitialize: These functions dereference or free any objects pointed to by the self pointer's
+ * value, but they don't actually free the self pointer. This is useful for stack-allocated objects
+ * which point to heap-allocated objects.
+ * - destruct: This dereferences or frees memory pointed to by the self argument, and all the
+ * pointers on the self argument.
+ */
+
{% for standard_library in standard_libraries %}
#include <{{standard_library}}>
{% endfor %}
typedef struct EnvironmentNode EnvironmentNode;
struct Environment;
typedef struct Environment Environment;
+struct EnvironmentPool;
+typedef struct EnvironmentPool EnvironmentPool;
const char* const STRING_LITERAL_LIST[] = {
{% for string_literal in string_literal_list %}
STRING
};
+struct Closure;
+typedef struct Closure Closure;
+struct Closure
+{
+ Environment* closed;
+ Object (*call)(EnvironmentPool*, Environment*, size_t, Object*);
+};
+
union Instance
{
bool boolean;
- Object (*closure)(Environment*, size_t, Object*);
+ Closure closure;
int32_t integer;
const char* string;
};
struct Environment
{
- size_t referenceCount;
+ bool mark;
+ bool live;
+
Environment* parent;
EnvironmentNode* root;
};
-Environment* Environment_construct(Environment* parent)
+void Environment_initialize(Environment* self, Environment* parent)
{
- Environment* result = malloc(sizeof(Environment));
- result->referenceCount = 1;
- result->parent = parent;
- result->root = NULL;
- return result;
+ self->parent = parent;
+ self->root = NULL;
+
+ // We are currently only ever initializing environments at the beginning of running functions, so
+ // for now at least we can assume that we want it to be live immediately.
+ self->live = true;
}
-void Environment_destruct(Environment* self)
+void Environment_deinitialize(Environment* self)
{
- self->referenceCount--;
+ EnvironmentNode* next;
+ for(EnvironmentNode* node = self->root; node != NULL; node = next)
+ {
+ next = node->next;
+ free(node);
+ }
+}
- if(self->referenceCount == 0)
+void Environment_setLive(Environment* self, bool live)
+{
+ self->live = live;
+}
+
+void Environment_mark(Environment* self)
+{
+ if(self == NULL) return;
+ if(self->mark) return; // Prevents infinite recursion in the case of cycles
+
+ self->mark = true;
+
+ Environment_mark(self->parent);
+
+ for(EnvironmentNode* node = self->root; node != NULL; node = node->next)
{
- EnvironmentNode* next;
- for(EnvironmentNode* node = self->root; node != NULL; node = next)
+ switch(node->value.type)
{
- // No objects are allocated on the heap (yet!) so we don't need to free anything else
- next = node->next;
- free(node);
+ case BOOLEAN:
+ case INTEGER:
+ case STRING:
+ break;
+
+ case CLOSURE:
+ Environment_mark(node->value.instance.closure.closed);
+ break;
+
+ default:
+ assert(false);
}
- free(self);
}
}
assert(false);
}
+# define POOL_SIZE 64
+struct EnvironmentPool
+{
+ int8_t freeIndex;
+ bool allocatedFlags[POOL_SIZE];
+ Environment environments[POOL_SIZE];
+ EnvironmentPool* overflow;
+};
+
+EnvironmentPool* EnvironmentPool_construct();
+void EnvironmentPool_initialize(EnvironmentPool*);
+void EnvironmentPool_deinitialize(EnvironmentPool*);
+void EnvironmentPool_destruct(EnvironmentPool*);
+
+EnvironmentPool* EnvironmentPool_construct()
+{
+ EnvironmentPool* result = malloc(sizeof(EnvironmentPool));
+ EnvironmentPool_initialize(result);
+ return result;
+}
+
+void EnvironmentPool_initialize(EnvironmentPool* self)
+{
+ self->overflow = NULL;
+ self->freeIndex = 0;
+
+ for(size_t i = 0; i < POOL_SIZE; i++)
+ {
+ self->allocatedFlags[i] = false;
+ self->environments[i].live = false;
+ }
+}
+
+void EnvironmentPool_deinitialize(EnvironmentPool* self)
+{
+ // We can assume if this is being called, none of the Environments are live
+ for(int8_t i = 0; i < POOL_SIZE; i++)
+ {
+ if(self->allocatedFlags[i]) Environment_deinitialize(&(self->environments[i]));
+ }
+
+ EnvironmentPool_destruct(self->overflow);
+}
+
+void EnvironmentPool_destruct(EnvironmentPool* self)
+{
+ if(self == NULL) return;
+ EnvironmentPool_deinitialize(self);
+ free(self);
+}
+
+void EnvironmentPool_GC(EnvironmentPool* self)
+{
+ // Unmark all the environments
+ for(EnvironmentPool* current = self; current != NULL; current = current->overflow)
+ {
+ for(int8_t i = 0; i < POOL_SIZE; i++)
+ {
+ current->environments[i].mark = false;
+ }
+ }
+
+ // Mark live enviroments and environments referenced by live environments
+ for(EnvironmentPool* current = self; current != NULL; current = current->overflow)
+ {
+ for(int8_t i = 0; i < POOL_SIZE; i++)
+ {
+ if(current->environments[i].live)
+ {
+ Environment_mark(&(current->environments[i]));
+ }
+ }
+ }
+
+ // TODO We never free pools until the very end--we could free a pool if two pools are empty
+ for(EnvironmentPool* current = self; current != NULL; current = current->overflow)
+ {
+ for(int8_t i = POOL_SIZE - 1; i >= 0; i--)
+ {
+ if(!current->environments[i].mark && current->allocatedFlags[i])
+ {
+ Environment_deinitialize(&(current->environments[i]));
+ current->allocatedFlags[i] = false;
+ current->freeIndex = i;
+ }
+ }
+ }
+}
+
+Environment* EnvironmentPool_allocate(EnvironmentPool* self)
+{
+ for(EnvironmentPool* current = self; current != NULL; current = current->overflow)
+ {
+ for(; current->freeIndex < POOL_SIZE; current->freeIndex++)
+ {
+ if(!current->allocatedFlags[current->freeIndex])
+ {
+ current->allocatedFlags[current->freeIndex] = true;
+ return &(current->environments[current->freeIndex]);
+ }
+ }
+ }
+
+ EnvironmentPool_GC(self);
+
+ EnvironmentPool* previous;
+ for(EnvironmentPool* current = self; current != NULL; current = current->overflow)
+ {
+ for(; current->freeIndex < POOL_SIZE; current->freeIndex++)
+ {
+ if(!current->allocatedFlags[current->freeIndex])
+ {
+ current->allocatedFlags[current->freeIndex] = true;
+ return &(current->environments[current->freeIndex]);
+ }
+ else
+ {
+ previous = current;
+ }
+ }
+ }
+
+ previous->overflow = EnvironmentPool_construct();
+ return EnvironmentPool_allocate(previous->overflow);
+}
+
Object integerLiteral(int32_t literal)
{
Object result;
{% endfor %}
{% if 'pow' in builtins %}
-Object builtin$pow$implementation(Environment* parent, size_t argc, Object* args)
+Object builtin$pow$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Object* args)
{
assert(argc == 2);
return result;
}
-Object builtin$pow = { CLOSURE, (Instance)builtin$pow$implementation };
+Object builtin$pow = { CLOSURE, (Instance)(Closure){ NULL, builtin$pow$implementation } };
{% endif %}
{% if 'print' in builtins %}
-Object builtin$print$implementation(Environment* parent, size_t argc, Object* args)
+Object builtin$print$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Object* args)
{
for(size_t i = 0; i < argc; i++)
{
fputs(output.instance.boolean ? "true" : "false", stdout);
break;
+ case CLOSURE:
+ // TODO Print something better
+ printf("<Closure>");
+ break;
+
case INTEGER:
printf("%" PRId32, output.instance.integer);
break;
return FALSE;
}
-Object builtin$print = { CLOSURE, (Instance)builtin$print$implementation };
+Object builtin$print = { CLOSURE, (Instance)(Closure){ NULL, builtin$print$implementation } };
{% endif %}
{% for function_definition in function_definition_list %}
-Object user${{function_definition.name}}$implementation(Environment* parent, size_t argc, Object* args)
+Object user${{function_definition.name}}$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Object* args)
{
- Environment* environment = Environment_construct(parent);
+ assert(argc == {{ function_definition.argument_name_list|length }});
+
+ Environment* environment = EnvironmentPool_allocate(environmentPool);
+ Environment_initialize(environment, parent);
+
+ {% for argument_name in function_definition.argument_name_list %}
+ Environment_set(environment, "{{ argument_name }}", args[{{ loop.index0 }}]);
+ {% endfor %}
{% for statement in function_definition.statement_list[:-1] %}
{{ generate_statement(statement) }}
{% endfor %}
Object result = {{ generate_statement(function_definition.statement_list[-1]) }}
- Environment_destruct(environment);
+
+ Environment_setLive(environment, false);
return result;
}
-Object user${{function_definition.name}} = { CLOSURE, (Instance)user${{function_definition.name}}$implementation };
{% endfor %}
-
int main(int argc, char** argv)
{
- Environment* environment = Environment_construct(NULL);
+ EnvironmentPool* environmentPool = EnvironmentPool_construct();
+ Environment* environment = EnvironmentPool_allocate(environmentPool);
+ Environment_initialize(environment, NULL);
// TODO Use the symbol from SYMBOL_LIST
{% for builtin in builtins %}
{{ generate_statement(statement) }}
{% endfor %}
- Environment_destruct(environment);
-
+ Environment_setLive(environment, false);
+ EnvironmentPool_destruct(environmentPool);
return 0;
}
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