scc

Simple C99 Compiler
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commit cae714c448ebdea4a6de048b012927b96be9b628
parent c1768b2e370906fc8418bc26cd69d88529c8c96b
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Mon, 14 Apr 2014 10:38:09 +0200

Check against assigns to const variables

It is implementation defined what happens in that cases, and
I choose report an error.

Diffstat:
expr.c | 8+++++++-
types.c | 2+-
2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/expr.c b/expr.c @@ -511,9 +511,10 @@ ternary(void) static Node * assign(void) { - register Node *np1 = ternary(), *np2; + register Node *np1, *np2; char *err; + np1 = ternary(); for (;;) { register char op; @@ -535,6 +536,8 @@ assign(void) np2 = assign(); if (!np1->b.lvalue) goto nolvalue; + if (isconst(np1->type->op)) + goto const_mod; /* TODO: if it necessary a 0 comparision? */ if ((np2 = convert(np2, np1->type)) == NULL) goto incompatibles; @@ -543,6 +546,9 @@ assign(void) return_np: return np1; +const_mod: + err = "const value modified"; + goto error; nolvalue: err = "lvalue required as left operand of assignment"; goto error; diff --git a/types.c b/types.c @@ -144,7 +144,7 @@ mktype(Type *tp, uint8_t op, case ARY: letter = 'V'; break; case ENUM: letter = 'E'; break; case STRUCT: letter = 'S'; break; - default: abort(); + default: letter = tp->letter; } bp = xmalloc(sizeof(*bp)); bp->next = *tbl;