more work on local variables

3 files changed, 111 insertions, 16 deletions

diff --git a/ecomp-c/ec.c b/ecomp-c/ec.c
index c98c766..46ee4b4 100644
--- a/ecomp-c/ec.c
+++ b/ecomp-c/ec.c
@@ -692,6 +692,7 @@ typedef struct Scope {
 	int label_no;
 	struct Symbol *symbol;
 	struct Scope *parent;
+	int size_locals;
 } Scope;
 
 static Scope *global_scope;
@@ -1028,10 +1029,28 @@ static void emit_expression_code( ExpressionNode *node, Scope *scope )
 		case EXPRESSION_NODE_TYPE_VAR:
 			switch( get_size( node->symbol ) ) {
 				case 4:
-					Emit( "mov eax, [%s]\n", node->symbol->name );
+					/* TODO: cleanup local global variable access */
+					if( node->symbol->offset == 0 ) {
+						Emit( "mov eax, [%s]\n", node->symbol->name );
+					} else {
+						Emit( "push ebp\n" );
+						Emit( "pop ebx\n" );
+						Emit( "mov eax, %d\n", node->symbol->offset );
+						Emit( "sub ebx, eax\n" );
+						Emit( "mov eax, [ebx]\n" );
+					}
 					break;
 				case 1:
-					Emit( "mov al, [%s]\n", node->symbol->name );
+					/* TODO: cleanup local global variable access */
+					if( node->symbol->offset == 0 ) {
+						Emit( "mov al, [%s]\n", node->symbol->name );
+					} else {
+						Emit( "push ebp\n" );
+						Emit( "pop ebx\n" );
+						Emit( "mov eax, %d\n", node->symbol->offset );
+						Emit( "sub ebx, eax\n" );
+						Emit( "mov al, [ebx]\n" );
+					}
 					break;
 				default:
 					Abort( "Unhandled size %d when reading register from memory", node->symbol->size );
@@ -1355,14 +1374,35 @@ static void parseAssignment( Scope *scope )
 		Emit( "\n" );
 
 		emit_expression_code( node, scope );
-		Emit( "pop eax\n" );
 
 		switch( get_size( symbol ) ) {
 			case 4:
-				Emit( "mov [%s], eax\n", symbol->name );
+				/* TODO: cleanup local global variable access */
+				if( symbol->offset == 0 ) {
+					Emit( "pop eax\n" );
+					Emit( "mov [%s], eax\n", symbol->name );
+				} else {
+					Emit( "push ebp\n" );
+					Emit( "pop ebx\n" );
+					Emit( "mov eax, %d\n", symbol->offset );
+					Emit( "sub ebx, eax\n" );
+					Emit( "pop eax\n" );
+					Emit( "mov [ebx], eax\n" );
+				}
 				break;
 			case 1:
-				Emit( "mov [%s], al\n", symbol->name );
+				/* TODO: cleanup local global variable access */
+				if( symbol->offset == 0 ) {
+					Emit( "pop eax\n" );
+					Emit( "mov [%s], al\n", symbol->name );
+				} else {
+					Emit( "push ebp\n" );
+					Emit( "pop ebx\n" );
+					Emit( "mov eax, %d\n", symbol->offset );
+					Emit( "sub ebx, eax\n" );
+					Emit( "pop eax\n" );
+					Emit( "mov [ebx], al\n" );
+				}
 				break;
 			default:
 				Abort( "Unhandled size %d when storing register immediately to memory", symbol->size );
@@ -1962,7 +2002,7 @@ static void parseProcedureBlock( Scope *scope )
 	if( sym == S_const || sym == S_var || sym == S_begin ) {
 
 		Symbol *sym;
-		int size_locals;
+		int offset;
 
 		Emit( "; PROC %s\n", symbol->name );
 		
@@ -1982,30 +2022,75 @@ static void parseProcedureBlock( Scope *scope )
 
 		parseProcedureDeclarationBlock( symbol->scope );
 		
-		size_locals = 0;
+		/* compute sizes of all locals */
+		offset = 4;
+		scope->size_locals = 0;
 		sym = symbol->scope->symbol;
 		while( sym != NULL ) {
 			if( sym->class == SYMBOL_CLASS_VARIABLE ) {
-				size_locals += get_size( sym );
+				int size = get_size( sym );
+				scope->size_locals += size;
+				sym->offset = offset;
+				offset += size;
 			}
 			sym = sym->next;
 		}
 		
-		if( size_locals > 0 ) {
-			Emit( "mov eax, %d\n", size_locals );
+		/* reserve space on stack */
+		if( scope->size_locals > 0 ) {
+			Emit( "mov eax, %d\n", scope->size_locals );
 			Emit( "sub esp, eax\n" );
 		}
 		
+		/* initialize local variables (sort of reserve_initialize_local)
+		 * at runtime (every time the stack is created for that procedure) */
+		sym = symbol->scope->symbol;
+		while( sym != NULL ) {
+			if( sym->class == SYMBOL_CLASS_VARIABLE ) {
+				/* TODO: use type here! */
+				int size = get_size( sym );
+				switch( size ) {
+					case 4:
+						/* TODO: cleanup local global variable access */
+						Emit( "push ebp\n" );
+						Emit( "pop ebx\n" );
+						Emit( "mov eax, %d\n", sym->offset );
+						Emit( "sub ebx, eax\n" );
+						Emit( "mov eax, %d\n", sym->integer_value );
+						Emit( "mov [ebx], eax\n" );
+						break;
+					case 1:
+						/* TODO: cleanup local global variable access */
+						Emit( "push ebp\n" );
+						Emit( "pop ebx\n" );
+						Emit( "mov eax, %d\n", sym->offset );
+						Emit( "sub ebx, eax\n" );
+						Emit( "mov eax, %d\n", sym->boolean_value );
+						Emit( "mov [ebx], al\n" );
+						break;
+					default:
+						Abort( "Not handled case when initializing local variable '%s' on stack", symbol->name );
+				}
+			}
+			sym = sym->next;
+		}
+		
 		/* TODO: allocate space on stack for local variables (and
 		 * parameters) */
 		/* TODO: assign symbols to relative addresses (base pointer) */
 		/* TODO: initialize local variables */
 
 		parseStatementBlock( symbol->scope );
-		
-		free_scope( symbol->scope );
-		
+				
 		/* discard locals, reset base pointer */
+
+		if( scope->size_locals > 0 ) {
+			Emit( "mov eax, %d\n", scope->size_locals );
+			Emit( "add esp, eax\n" );
+		}
+
+		free_scope( symbol->scope );
+
 		Emit( "pop ebp\n" );
 		
 		Emit( "ret\n" );
diff --git a/ecomp-c/tests/procedure_local_variables.e b/ecomp-c/tests/procedure_local_variables.e
index 2838203..31373ea 100644
--- a/ecomp-c/tests/procedure_local_variables.e
+++ b/ecomp-c/tests/procedure_local_variables.e
@@ -5,18 +5,20 @@
 module procedure_call;
 
 var
-	i : integer := 0;
+	i : integer := 1;
 	
 procedure proc;
+
 const
 	C : integer = 42;
+	
 var
 	j : integer;
 	k : integer := C;
 	
 begin
 	j := i;
-	i := k;
+	i := j;
 end
 
 begin
diff --git a/ecomp-c/tests/procedure_scoping.easm b/ecomp-c/tests/procedure_scoping.easm
index 72a9dfb..8f6dc6f 100644
--- a/ecomp-c/tests/procedure_scoping.easm
+++ b/ecomp-c/tests/procedure_scoping.easm
@@ -15,6 +15,8 @@ pop ebp
 ; DECL x -> array 2 of integer, array 2 of integer = { ... }
 ; DECL y -> array 3 of integer, array 3 of integer = { ... }
 ; DECL z -> integer, 0
+mov eax, 4
+sub esp, eax
 ; LET x[2 ] <- 3 
 mov eax, 2
 push eax
@@ -34,8 +36,14 @@ mov [ebx], eax
 ; LET z <- 4 
 mov eax, 4
 push eax
+push ebp
+pop ebx
+mov eax, 4
+sub ebx, eax
 pop eax
-mov [z], eax
+mov [ebx], eax
+mov eax, 4
+add esp, eax
 pop ebp
 ret
 ; PROC B