scc

Simple C99 Compiler
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commit 3eb5942278feaee4a0644ac7fed545ba19c052e6
parent 2149f9e083fe7d75fa41e011ba8923b5c8a7da2e
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Mon, 21 Apr 2014 09:13:24 +0200

Use a pointer function in assign()

Instead of using a big switch with the semantic actions of
each operator is better use a pointer function.

Diffstat:
code.c | 2+-
expr.c | 62++++++++++++++++++++++++++++----------------------------------
2 files changed, 29 insertions(+), 35 deletions(-)

diff --git a/code.c b/code.c @@ -248,7 +248,7 @@ symcode(Symbol *sym) { Node *np; - np = node(emitsym, inttype, SYM(sym), 0); + np = node(emitsym, sym->type, SYM(sym), 0); np->b.symbol = 1; np->b.constant = 1; return np; diff --git a/expr.c b/expr.c @@ -284,27 +284,9 @@ eval(Node *np) static Node * assignop(char op, Node *np1, Node *np2) { - char *err; - - if (!np1->b.lvalue) - goto nolvalue; - if (isconst(np1->type->op)) - goto const_mod; - np2 = eval(np2); if ((np2 = convert(np2, np1->type, 0)) == NULL) - goto incompatibles; + error("incompatible types when assigning"); return bincode(op, np1->type, np1, np2); - -const_mod: - err = "const value modified"; - goto error; -nolvalue: - err = "lvalue required as left operand of assignment"; - goto error; -incompatibles: - err = "incompatible types when assigning"; -error: - error(err); } static Node * @@ -691,29 +673,41 @@ ternary(void) static Node * assign(void) { - register Node *np; + register Node *np, *(*fun)(char , Node *, Node *); + register char op; + char *err; np = ternary(); for (;;) { - register char op; - switch (yytoken) { - case '=': op = OASSIGN; break; - case MUL_EQ: op = OA_MUL; break; - case DIV_EQ: op = OA_DIV; break; - case MOD_EQ: op = OA_MOD; break; - case ADD_EQ: op = OA_ADD; break; - case SUB_EQ: op = OA_SUB; break; - case SHL_EQ: op = OA_SHL; break; - case SHR_EQ: op = OA_SHR; break; - case AND_EQ: op = OA_AND; break; - case XOR_EQ: op = OA_XOR; break; - case OR_EQ: op = OA_OR; break; + case '=': op = OASSIGN; fun = assignop; break; + case MUL_EQ: op = OA_MUL; fun = arithmetic; break; + case DIV_EQ: op = OA_DIV; fun = arithmetic; break; + case MOD_EQ: op = OA_MOD; fun = bitlogic; break; + case ADD_EQ: op = OA_ADD; fun = arithmetic; break; + case SUB_EQ: op = OA_SUB; fun = arithmetic; break; + case SHL_EQ: op = OA_SHL; fun = bitlogic; break; + case SHR_EQ: op = OA_SHR; fun = bitlogic; break; + case AND_EQ: op = OA_AND; fun = bitlogic; break; + case XOR_EQ: op = OA_XOR; fun = bitlogic; break; + case OR_EQ: op = OA_OR; fun = bitlogic; break; default: return np; } + if (!np->b.lvalue) + goto nolvalue; + if (isconst(np->type->op)) + goto const_mod; next(); - np = assignop(op, np, assign()); + np = (fun)(op, np, eval(assign())); } +const_mod: + err = "const value modified"; + goto error; +nolvalue: + err = "lvalue required as left operand of assignment"; + goto error; +error: + error(err); } Node *