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analyze.c
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analyze.c
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/****************************************************/
/* File: analyze.c */
/* Semantic analyzer implementation */
/* for the TINY compiler */
/* Compiler Construction: Principles and Practice */
/* Kenneth C. Louden */
/****************************************************/
#include "globals.h"
#include "symtab.h"
#include "analyze.h"
#include "util.h"
/* counter for variable memory locations */
static int location = 0;
static char * scope = "~";
char * getNewScope(TreeNode * t)
{ char *result = NULL;
if (t->nodekind == StmtK)
{ if (t->kind.stmt == FunctionK)
{ result = (char *)malloc(sizeof(char) * (strlen(scope) + strlen(t->attr.name) + 3));
sprintf(result, "%s:%s", scope, t->attr.name);
}
else if (t->kind.stmt == CompoundK)
{ result = (char *)malloc(sizeof(char) * (strlen(scope) + 12));
sprintf(result, "%s:%d\0", scope, t->lineno);
}
}
if (result == NULL)
{ result = (char *)malloc(sizeof(char) * (strlen(scope) + 2));
strcpy(result, scope);
}
return result;
}
/* Procedure traverse is a generic recursive
* syntax tree traversal routine:
* it applies preProc in preorder and postProc
* in postorder to tree pointed to by t
*/
static void traverse( TreeNode * t,
void (* preProc) (TreeNode *),
void (* postProc) (TreeNode *) )
{ if (t != NULL)
{
preProc(t);
{ int i;
char * scopeBackup = scope;
int locationBackup = location;
scope = getNewScope(t);
location = 0;
for (i=0; i < MAXCHILDREN; i++)
traverse(t->child[i],preProc,postProc);
free(scope);
scope = scopeBackup;
location = locationBackup;
}
postProc(t);
traverse(t->sibling,preProc,postProc);
}
}
/* nullProc is a do-nothing procedure to
* generate preorder-only or postorder-only
* traversals from traverse
*/
static void nullProc(TreeNode * t)
{ if (t==NULL) return;
else return;
}
/* Procedure insertNode inserts
* identifiers stored in t into
* the symbol table
*/
static void insertNode( TreeNode * t)
{ int isArray = 0;
switch (t->nodekind)
{ case StmtK:
switch (t->kind.stmt)
{ case FunctionK:
if (st_lookup(scope,t->attr.name) == NULL)
/* not yet in table, so treat as new definition */
st_insert(scope,t->attr.name,t->type,t->lineno,location++, isArray);
else
/* already in table, so ignore location,
add line number of use only */
//st_insert(t->attr.name,t->lineno,0);
fprintf(listing, "error:%d: %s is already declared\n", t->lineno, t->attr.name);
break;
default:
break;
}
break;
case ExpK:
switch (t->kind.exp)
{ case VarArrayK:
isArray = 1;
case VarK:
case SingleParamK:
case ArrayParamK:
if (t->attr.name != NULL && st_lookup_excluding_parent(scope,t->attr.name) == NULL)
{
/* not yet in table, so treat as new definition */
st_insert(scope,t->attr.name,t->type,t->lineno,location++, isArray);
if(t->kind.exp == VarArrayK)
location += t->child[0]->attr.val - 1;
}
else if(t->attr.name != NULL)
/* already in table, so ignore location,
add line number of use only */
//st_insert(t->attr.name,t->lineno,0);
fprintf(listing, "error:%d: %s is already declared\n", t->lineno, t->attr.name);
break;
case IdK:
case IdArrayK:
case CallK:
if (st_lookup(scope,t->attr.name) == NULL)
fprintf(listing, "error:%d: %s is not declared\n", t->lineno, t->attr.name);
else
{
if(checkArray(scope, t->attr.name) == 1)
t->kind.exp = IdArrayK;
addline(scope,t->attr.name,t->lineno,0);
}
break;
default:
break;
}
break;
default:
break;
}
}
void insertBuiltinFunctions(TreeNode ** syntaxTree)
{ TreeNode *input = newStmtNode(FunctionK);
input->sibling = *syntaxTree;
*syntaxTree = input;
input->lineno = 0;
input->attr.name = malloc(sizeof(char) * (strlen("input") + 1));
strcpy(input->attr.name, "input");
input->type = Integer;
TreeNode *output = newStmtNode(FunctionK);
output->sibling = *syntaxTree;
*syntaxTree = output;
output->lineno = 0;
output->attr.name = malloc(sizeof(char) * (strlen("output") + 1));
strcpy(output->attr.name, "output");
output->type = Void;
TreeNode *param = newExpNode(SingleParamK);
param->type = Integer;
param->attr.name = malloc(sizeof(char) * (strlen("arg") + 1));
strcpy(param->attr.name, "arg");
param->lineno = 0;
output->child[0] = param;
}
/* Function buildSymtab constructs the symbol
* table by preorder traversal of the syntax tree
*/
TreeNode* buildSymtab(TreeNode * syntaxTree)
{ insertBuiltinFunctions(&syntaxTree);
traverse(syntaxTree,insertNode,nullProc);
if (TraceAnalyze)
{ fprintf(listing,"\nSymbol table:\n\n");
printSymTab(listing);
}
if (st_lookup("~", "main") == NULL)
{ fprintf(listing, "There is no main function");
Error = TRUE;
}
return syntaxTree;
}
static void typeError(TreeNode * t, char * message)
{ fprintf(listing,"Type error at line %d: %s\n",t->lineno,message);
Error = TRUE;
}
/* Procedure checkNode performs
* type checking at a single tree node
*/
static void checkNode(TreeNode * t)
{ switch (t->nodekind)
{ case ExpK:
switch (t->kind.exp)
{ BucketList bucket;
case OpK:
break;
case VarK:
case VarArrayK:
if (t->type == Void)
typeError(t, "variable can not be void type");
break;
case ConstK:
break;
case IdK:
break;
case IdArrayK:
break;
case CallK:
break;
case AssignK:
if (t->child[1]->kind.exp == IdK || t->child[1]->kind.exp == CallK || t->child[1]->kind.exp == IdArrayK)
{ bucket = st_lookup(scope, t->child[1]->attr.name);
if (bucket->type != Integer)
typeError(t->child[1], "rvalue must be instger type");
}
else if (t->child[1]->type != Integer)
typeError(t->child[1], "rvalue must be instger type");
break;
case SingleParamK:
break;
case ArrayParamK:
break;
}
break;
case StmtK:
switch (t->kind.stmt)
{ char *tmp;
BucketList l;
case IfK:
break;
case FunctionK:
break;
case CompoundK:
break;
case WhileK:
break;
case ReturnK:
tmp = (char *)malloc(sizeof(char) * (strlen(scope) + 1));
strcpy(tmp, scope);
strtok(tmp, ":");
char *functionName = strtok(NULL, ":");
l = st_lookup("~", functionName);
if (l == NULL)
{ char *tmp;
tmp = (char *)malloc(sizeof(char) * (strlen(functionName) + strlen("there is no ") + 1));
sprintf(tmp, "%s%s", "there is no %s", functionName);
typeError(t, tmp);
free(tmp);
}
else if (l->type != Integer)
typeError(t, "Void function can not return a value");
free(tmp);
break;
}
break;
default:
break;
}
}
/* Procedure typeCheck performs type checking
* by a postorder syntax tree traversal
*/
void typeCheck(TreeNode * syntaxTree)
{ traverse(syntaxTree,nullProc,checkNode);
}