changed SwitchJmp emitter (but still broken in some cases)

[libfirm] / ir / be / ia32 / ia32_emitter.c

diff --git a/ir/be/ia32/ia32_emitter.c b/ir/be/ia32/ia32_emitter.c
index 6841c90..a86a40f 100644 (file)
--- a/ir/be/ia32/ia32_emitter.c
+++ b/ir/be/ia32/ia32_emitter.c
@@ -873,7 +873,7 @@ static int ia32_cmp_branch_t(const void *a, const void *b) {
 static void emit_ia32_SwitchJmp(const ir_node *irn, ia32_emit_env_t *emit_env) {
        unsigned long       interval;
        char                buf[SNPRINTF_BUF_LEN];
-       int                 last_value, i, pn, do_jmp_tbl = 1;
+       int                 last_value, i, pn;
        jmp_tbl_t           tbl;
        ir_node            *proj;
        const ir_edge_t    *edge;
@@ -920,83 +920,59 @@ static void emit_ia32_SwitchJmp(const ir_node *irn, ia32_emit_env_t *emit_env) {
        /* two-complement's magic make this work without overflow */
        interval = tbl.max_value - tbl.min_value;
 
-       /* check value interval */
-       if (interval > 16 * 1024) {
-               do_jmp_tbl = 0;
-       }
+       /* emit the table */
+       if (tbl.min_value != 0) {
+               lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "sub [%1S-%d], %u", irn, tbl.min_value * 4, interval);
+               lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmp DWORD PTR [%1S-%d], %u", irn, tbl.min_value * 4, interval);
+               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* first switch value is not 0 */");
 
-       /* check ratio of value interval to number of branches */
-       if ((float)(interval + 1) / (float)tbl.num_branches > 8.0) {
-               do_jmp_tbl = 0;
+               IA32_DO_EMIT(irn);
        }
+       else {
+               lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmp %1S, %u", irn, interval);
+               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* compare for switch */");
 
-       if (do_jmp_tbl) {
-               /* emit the table */
-               if (tbl.min_value != 0) {
-                       lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmpl %lu, -%d(%1S)",
-                               interval, tbl.min_value, irn);
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* first switch value is not 0 */");
+               IA32_DO_EMIT(irn);
+       }
 
-                       IA32_DO_EMIT(irn);
-               }
-               else {
-                       lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmpl %lu, %1S", interval, irn);
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* compare for switch */");
+       snprintf(cmd_buf, SNPRINTF_BUF_LEN, "ja %s", get_cfop_target(tbl.defProj, buf));
+       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default jump if out of range  */");
+       IA32_DO_EMIT(irn);
 
-                       IA32_DO_EMIT(irn);
-               }
+       if (tbl.num_branches > 1) {
+               /* create table */
 
-               snprintf(cmd_buf, SNPRINTF_BUF_LEN, "ja %s", get_cfop_target(tbl.defProj, buf));
-               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default jump if out of range  */");
+               lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "jmp %s[%1S*4]", tbl.label, irn);
+               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* get jump table entry as target */");
                IA32_DO_EMIT(irn);
 
-               if (tbl.num_branches > 1) {
-                       /* create table */
-
-                       lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "jmp [%1S*4+%s]", irn, tbl.label);
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* get jump table entry as target */");
-                       IA32_DO_EMIT(irn);
+               fprintf(F, "\t.section\t.rodata\n");
+               fprintf(F, "\t.align 4\n");
 
-                       fprintf(F, "\t.section\t.rodata\n");
-                       fprintf(F, "\t.align 4\n");
+               fprintf(F, "%s:\n", tbl.label);
 
-                       fprintf(F, "%s:\n", tbl.label);
-
-                       snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.branches[0].target, buf));
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */\n",  tbl.branches[0].value);
-                       IA32_DO_EMIT(irn);
+               snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.branches[0].target, buf));
+               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */\n",  tbl.branches[0].value);
+               IA32_DO_EMIT(irn);
 
-                       last_value = tbl.branches[0].value;
-                       for (i = 1; i < tbl.num_branches; ++i) {
-                               while (++last_value < tbl.branches[i].value) {
-                                       snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.defProj, buf));
-                                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default case */");
-                                       IA32_DO_EMIT(irn);
-                               }
-                               snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.branches[i].target, buf));
-                               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */", last_value);
+               last_value = tbl.branches[0].value;
+               for (i = 1; i < tbl.num_branches; ++i) {
+                       while (++last_value < tbl.branches[i].value) {
+                               snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.defProj, buf));
+                               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default case */");
                                IA32_DO_EMIT(irn);
                        }
-
-                       fprintf(F, "\t.text");
-               }
-               else {
-                       /* one jump is enough */
-                       snprintf(cmd_buf, SNPRINTF_BUF_LEN, "jmp %s", get_cfop_target(tbl.branches[0].target, buf));
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* only one case given */");
-                       IA32_DO_EMIT(irn);
-               }
-       }
-       else { // no jump table
-               for (i = 0; i < tbl.num_branches; ++i) {
-                       lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmpl %d, %1S", tbl.branches[i].value, irn);
-                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */", i);
+                       snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.branches[i].target, buf));
+                       snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */", last_value);
                        IA32_DO_EMIT(irn);
-                       fprintf(F, "\tje %s\n", get_cfop_target(tbl.branches[i].target, buf));
                }
 
-               snprintf(cmd_buf, SNPRINTF_BUF_LEN, "jmp %s", get_cfop_target(tbl.defProj, buf));
-               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default case */");
+               fprintf(F, "\t.text");
+       }
+       else {
+               /* one jump is enough */
+               snprintf(cmd_buf, SNPRINTF_BUF_LEN, "jmp %s", get_cfop_target(tbl.branches[0].target, buf));
+               snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* only one case given */");
                IA32_DO_EMIT(irn);
        }