isl_basic_set_opt: avoid invalid access on error path

[platform/upstream/isl.git] / isl_blk.c

diff --git a/isl_blk.c b/isl_blk.c
index d581f2d..29844d5 100644 (file)
--- a/isl_blk.c
+++ b/isl_blk.c
@@ -1,7 +1,7 @@
 /*
  * Copyright 2008-2009 Katholieke Universiteit Leuven
  *
- * Use of this software is governed by the GNU LGPLv2.1 license
+ * Use of this software is governed by the MIT license
  *
  * Written by Sven Verdoolaege, K.U.Leuven, Departement
  * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
@@ -10,6 +10,9 @@
 #include <isl/blk.h>
 #include <isl_ctx_private.h>
 
+/* The maximal number of cache misses before first element is evicted */
+#define ISL_BLK_MAX_MISS       100
+
 struct isl_blk isl_blk_empty()
 {
        struct isl_blk block;
@@ -36,31 +39,7 @@ int isl_blk_is_error(struct isl_blk block)
        return block.size == -1 && block.data == NULL;
 }
 
-struct isl_blk isl_blk_alloc(struct isl_ctx *ctx, size_t n)
-{
-       int i;
-       struct isl_blk block;
-
-       if (ctx->n_cached) {
-               int best = 0;
-               for (i = 1; ctx->cache[best].size != n && i < ctx->n_cached; ++i) {
-                       if (ctx->cache[best].size < n) {
-                               if (ctx->cache[i].size > ctx->cache[best].size)
-                                       best = i;
-                       } else if (ctx->cache[i].size >= n &&
-                                  ctx->cache[i].size < ctx->cache[best].size)
-                                       best = i;
-               }
-               block = ctx->cache[best];
-               if (--ctx->n_cached != best)
-                       ctx->cache[best] = ctx->cache[ctx->n_cached];
-       } else
-               block = isl_blk_empty();
-
-       return isl_blk_extend(ctx, block, n);
-}
-
-struct isl_blk isl_blk_extend(struct isl_ctx *ctx, struct isl_blk block,
+static struct isl_blk extend(struct isl_ctx *ctx, struct isl_blk block,
                                size_t new_n)
 {
        int i;
@@ -92,6 +71,48 @@ static void isl_blk_free_force(struct isl_ctx *ctx, struct isl_blk block)
        free(block.data);
 }
 
+struct isl_blk isl_blk_alloc(struct isl_ctx *ctx, size_t n)
+{
+       int i;
+       struct isl_blk block;
+
+       block = isl_blk_empty();
+       if (n && ctx->n_cached) {
+               int best = 0;
+               for (i = 1; ctx->cache[best].size != n && i < ctx->n_cached; ++i) {
+                       if (ctx->cache[best].size < n) {
+                               if (ctx->cache[i].size > ctx->cache[best].size)
+                                       best = i;
+                       } else if (ctx->cache[i].size >= n &&
+                                  ctx->cache[i].size < ctx->cache[best].size)
+                                       best = i;
+               }
+               if (ctx->cache[best].size < 2 * n + 100) {
+                       block = ctx->cache[best];
+                       if (--ctx->n_cached != best)
+                               ctx->cache[best] = ctx->cache[ctx->n_cached];
+                       if (best == 0)
+                               ctx->n_miss = 0;
+               } else if (ctx->n_miss++ >= ISL_BLK_MAX_MISS) {
+                       isl_blk_free_force(ctx, ctx->cache[0]);
+                       if (--ctx->n_cached != 0)
+                               ctx->cache[0] = ctx->cache[ctx->n_cached];
+                       ctx->n_miss = 0;
+               }
+       }
+
+       return extend(ctx, block, n);
+}
+
+struct isl_blk isl_blk_extend(struct isl_ctx *ctx, struct isl_blk block,
+                               size_t new_n)
+{
+       if (isl_blk_is_empty(block))
+               return isl_blk_alloc(ctx, new_n);
+
+       return extend(ctx, block, new_n);
+}
+
 void isl_blk_free(struct isl_ctx *ctx, struct isl_blk block)
 {
        if (isl_blk_is_empty(block) || isl_blk_is_error(block))