Implement semi-binary emitter for SwitchJmp.

[r26657]

diff --git a/ir/be/ia32/ia32_emitter.c b/ir/be/ia32/ia32_emitter.c
index 818d8ba..2982a56 100644 (file)
--- a/ir/be/ia32/ia32_emitter.c
+++ b/ir/be/ia32/ia32_emitter.c
@@ -1213,28 +1213,21 @@ static int ia32_cmp_branch_t(const void *a, const void *b)
                return 1;
 }
 
-/**
- * Emits code for a SwitchJmp (creates a jump table if
- * possible otherwise a cmp-jmp cascade). Port from
- * cggg ia32 backend
- */
-static void emit_ia32_SwitchJmp(const ir_node *node)
+static void generate_jump_table(jmp_tbl_t *tbl, const ir_node *node)
 {
-       unsigned long       interval;
-       int                 last_value, i;
+       int                 i;
        long                pnc;
        long                default_pn;
-       jmp_tbl_t           tbl;
        ir_node            *proj;
        const ir_edge_t    *edge;
 
        /* fill the table structure */
-       get_unique_label(tbl.label, SNPRINTF_BUF_LEN, ".TBL_");
-       tbl.defProj      = NULL;
-       tbl.num_branches = get_irn_n_edges(node) - 1;
-       tbl.branches     = XMALLOCNZ(branch_t, tbl.num_branches);
-       tbl.min_value    = INT_MAX;
-       tbl.max_value    = INT_MIN;
+       get_unique_label(tbl->label, SNPRINTF_BUF_LEN, ".TBL_");
+       tbl->defProj      = NULL;
+       tbl->num_branches = get_irn_n_edges(node) - 1;
+       tbl->branches     = XMALLOCNZ(branch_t, tbl->num_branches);
+       tbl->min_value    = INT_MAX;
+       tbl->max_value    = INT_MIN;
 
        default_pn = get_ia32_condcode(node);
        i = 0;
@@ -1247,23 +1240,38 @@ static void emit_ia32_SwitchJmp(const ir_node *node)
 
                /* check for default proj */
                if (pnc == default_pn) {
-                       assert(tbl.defProj == NULL && "found two default Projs at SwitchJmp");
-                       tbl.defProj = proj;
+                       assert(tbl->defProj == NULL && "found two default Projs at SwitchJmp");
+                       tbl->defProj = proj;
                } else {
-                       tbl.min_value = pnc < tbl.min_value ? pnc : tbl.min_value;
-                       tbl.max_value = pnc > tbl.max_value ? pnc : tbl.max_value;
+                       tbl->min_value = pnc < tbl->min_value ? pnc : tbl->min_value;
+                       tbl->max_value = pnc > tbl->max_value ? pnc : tbl->max_value;
 
                        /* create branch entry */
-                       tbl.branches[i].target = proj;
-                       tbl.branches[i].value  = pnc;
+                       tbl->branches[i].target = proj;
+                       tbl->branches[i].value  = pnc;
                        ++i;
                }
 
        }
-       assert(i == tbl.num_branches);
+       assert(i == tbl->num_branches);
 
        /* sort the branches by their number */
-       qsort(tbl.branches, tbl.num_branches, sizeof(tbl.branches[0]), ia32_cmp_branch_t);
+       qsort(tbl->branches, tbl->num_branches, sizeof(tbl->branches[0]), ia32_cmp_branch_t);
+}
+
+/**
+ * Emits code for a SwitchJmp (creates a jump table if
+ * possible otherwise a cmp-jmp cascade). Port from
+ * cggg ia32 backend
+ */
+static void emit_ia32_SwitchJmp(const ir_node *node)
+{
+       unsigned long       interval;
+       int                 last_value, i;
+       jmp_tbl_t           tbl;
+
+       /* fill the table structure */
+       generate_jump_table(&tbl, node);
 
        /* two-complement's magic make this work without overflow */
        interval = tbl.max_value - tbl.min_value;
@@ -3398,6 +3406,67 @@ emit_jcc:
        }
 }
 
+static void bemit_switchjmp(const ir_node *node)
+{
+       unsigned long          interval;
+       int                    last_value;
+       int                    i;
+       jmp_tbl_t              tbl;
+       const arch_register_t *in;
+
+       /* fill the table structure */
+       generate_jump_table(&tbl, node);
+
+       /* two-complement's magic make this work without overflow */
+       interval = tbl.max_value - tbl.min_value;
+
+       in = get_in_reg(node, 0);
+       /* emit the table */
+       if (get_signed_imm_size(interval) == 1) {
+               bemit8(0x83); // cmpl $imm8, %in
+               bemit_modru(in, 7);
+               bemit8(interval);
+       } else {
+               bemit8(0x81); // cmpl $imm32, %in
+               bemit_modru(in, 7);
+               bemit32(interval);
+       }
+       bemit8(0x0F); // ja tbl.defProj
+       bemit8(0x87);
+       ia32_emitf(tbl.defProj, ".long %L - . - 4\n");
+
+       if (tbl.num_branches > 1) {
+               /* create table */
+               bemit8(0xFF); // jmp *tbl.label(,%in,4)
+               bemit8(MOD_IND | ENC_REG(4) | ENC_RM(0x04));
+               bemit8(ENC_SIB(2, reg_gp_map[in->index], 0x05));
+               be_emit_irprintf("\t.long %s\n", tbl.label);
+
+               be_gas_emit_switch_section(GAS_SECTION_RODATA);
+               be_emit_cstring(".align 4\n");
+               be_emit_irprintf("%s:\n", tbl.label);
+
+               last_value = tbl.branches[0].value;
+               for (i = 0; i != tbl.num_branches; ++i) {
+                       while (last_value != tbl.branches[i].value) {
+                               ia32_emitf(tbl.defProj, ".long %L\n");
+                               ++last_value;
+                       }
+                       ia32_emitf(tbl.branches[i].target, ".long %L\n");
+                       ++last_value;
+               }
+               be_gas_emit_switch_section(GAS_SECTION_TEXT);
+       } else {
+               /* one jump is enough */
+               panic("switch only has one case");
+               //ia32_emitf(tbl.branches[0].target, "\tjmp %L\n");
+       }
+
+       be_emit_write_line();
+
+       free(tbl.branches);
+}
+
 /**
  * Emits a return.
  */
@@ -3922,6 +3991,7 @@ static void ia32_register_binary_emitters(void)
        register_emitter(op_ia32_SubMem,        bemit_submem);
        register_emitter(op_ia32_SubMem8Bit,    bemit_submem8bit);
        register_emitter(op_ia32_SubSP,         bemit_subsp);
+       register_emitter(op_ia32_SwitchJmp,     bemit_switchjmp);
        register_emitter(op_ia32_Test,          bemit_test);
        register_emitter(op_ia32_Test8Bit,      bemit_test8bit);
        register_emitter(op_ia32_Xor,           bemit_xor);