value position allocation, fixing a possible endless loop in ir_values_overlap

[xonotic/gmqcc.git] / ast.c

diff --git a/ast.c b/ast.c
index c96594752168de3399d7987a5909f1c652ab95b6..49446a111d7035085c90981018c91b02e48f5e06 100644 (file)
--- a/ast.c
+++ b/ast.c
@@ -36,7 +36,7 @@
     ( (ast_node*)self )->node.destroy = (ast_node_delete*)destroyfn
 
 /* It must not be possible to get here. */
-static void _ast_node_destroy(ast_node *self)
+static GMQCC_NORETURN void _ast_node_destroy(ast_node *self)
 {
     fprintf(stderr, "ast node missing destroy()\n");
     abort();
@@ -772,7 +772,7 @@ bool ast_ifthen_codegen(ast_ifthen *self, ast_function *func, bool lvalue, ir_va
             return false;
     } else
         ontrue = NULL;
-    
+
     /* on-false path */
     if (self->on_false) {
         /* create on-false block */
@@ -793,7 +793,7 @@ bool ast_ifthen_codegen(ast_ifthen *self, ast_function *func, bool lvalue, ir_va
     /* Merge block were they all merge in to */
     merge = ir_function_create_block(func->ir_func, ast_function_label(func, "endif"));
     if (!merge)
-        return NULL;
+        return false;
 
     /* add jumps ot the merge block */
     if (ontrue && !ir_block_create_jump(ontrue, merge))
@@ -844,7 +844,7 @@ bool ast_ternary_codegen(ast_ternary *self, ast_function *func, bool lvalue, ir_
         return false;
 
     /* In the following, contraty to ast_ifthen, we assume both paths exist. */
-    
+
     /* generate the condition */
     func->curblock = cond;
     cgen = self->cond->expression.codegen;
@@ -865,7 +865,7 @@ bool ast_ternary_codegen(ast_ternary *self, ast_function *func, bool lvalue, ir_
         if (!(*cgen)((ast_expression*)(self->on_true), func, false, &trueval))
             return false;
     }
-    
+
     /* create on-false block */
     onfalse = ir_function_create_block(func->ir_func, ast_function_label(func, "tern_F"));
     if (!onfalse)
@@ -884,7 +884,7 @@ bool ast_ternary_codegen(ast_ternary *self, ast_function *func, bool lvalue, ir_
     /* create merge block */
     merge = ir_function_create_block(func->ir_func, ast_function_label(func, "tern_out"));
     if (!merge)
-        return NULL;
+        return false;
     /* jump to merge block */
     if (!ir_block_create_jump(ontrue, merge))
         return false;
@@ -925,26 +925,31 @@ bool ast_loop_codegen(ast_loop *self, ast_function *func, bool lvalue, ir_value
 {
     ast_expression_codegen *cgen;
 
-    ir_value *dummy;
-    ir_value *precond;
-    ir_value *postcond;
+    ir_value *dummy      = NULL;
+    ir_value *precond    = NULL;
+    ir_value *postcond   = NULL;
 
     /* Since we insert some jumps "late" so we have blocks
      * ordered "nicely", we need to keep track of the actual end-blocks
      * of expressions to add the jumps to.
      */
-    ir_block *bbody,      *end_bbody;
-    ir_block *bprecond,   *end_bprecond;
-    ir_block *bpostcond,  *end_bpostcond;
-    ir_block *bincrement, *end_bincrement;
-    ir_block *bout, *bin;
+    ir_block *bbody      = NULL, *end_bbody      = NULL;
+    ir_block *bprecond   = NULL, *end_bprecond   = NULL;
+    ir_block *bpostcond  = NULL, *end_bpostcond  = NULL;
+    ir_block *bincrement = NULL, *end_bincrement = NULL;
+    ir_block *bout       = NULL, *bin            = NULL;
+
+    /* let's at least move the outgoing block to the end */
+    size_t    bout_id;
 
     /* 'break' and 'continue' need to be able to find the right blocks */
-    ir_block *bcontinue = NULL;
-    ir_block *bbreak    = NULL;
+    ir_block *bcontinue     = NULL;
+    ir_block *bbreak        = NULL;
 
-    ir_block *old_bcontinue;
-    ir_block *old_bbreak;
+    ir_block *old_bcontinue = NULL;
+    ir_block *old_bbreak    = NULL;
+
+    ir_block *tmpblock      = NULL;
 
     (void)lvalue;
     (void)out;
@@ -1014,6 +1019,7 @@ bool ast_loop_codegen(ast_loop *self, ast_function *func, bool lvalue, ir_value
         bpostcond = end_bpostcond = NULL;
     }
 
+    bout_id = func->ir_func->blocks_count;
     bout = ir_function_create_block(func->ir_func, ast_function_label(func, "after_loop"));
     if (!bout)
         return false;
@@ -1072,15 +1078,16 @@ bool ast_loop_codegen(ast_loop *self, ast_function *func, bool lvalue, ir_value
         end_bincrement = func->curblock;
     }
 
+    /* In any case now, we continue from the outgoing block */
+    func->curblock = bout;
+
     /* Now all blocks are in place */
     /* From 'bin' we jump to whatever comes first */
-    if (bprecond       && !ir_block_create_jump(bin, bprecond))
-        return false;
-    else if (bbody     && !ir_block_create_jump(bin, bbody))
-        return false;
-    else if (bpostcond && !ir_block_create_jump(bin, bpostcond))
-        return false;
-    else if (             !ir_block_create_jump(bin, bout))
+    if      (bprecond)   tmpblock = bprecond;
+    else if (bbody)      tmpblock = bbody;
+    else if (bpostcond)  tmpblock = bpostcond;
+    else                 tmpblock = bout;
+    if (!ir_block_create_jump(bin, tmpblock))
         return false;
 
     /* From precond */
@@ -1099,26 +1106,22 @@ bool ast_loop_codegen(ast_loop *self, ast_function *func, bool lvalue, ir_value
     /* from body */
     if (bbody)
     {
-        if (bincrement     && !ir_block_create_jump(end_bbody, bincrement))
-            return false;
-        else if (bpostcond && !ir_block_create_jump(end_bbody, bpostcond))
-            return false;
-        else if (bprecond  && !ir_block_create_jump(end_bbody, bprecond))
-            return false;
-        else if              (!ir_block_create_jump(end_bbody, bout))
+        if      (bincrement) tmpblock = bincrement;
+        else if (bpostcond)  tmpblock = bpostcond;
+        else if (bprecond)   tmpblock = bprecond;
+        else                 tmpblock = bout;
+        if (!ir_block_create_jump(end_bbody, tmpblock))
             return false;
     }
 
     /* from increment */
     if (bincrement)
     {
-        if (bpostcond      && !ir_block_create_jump(end_bincrement, bpostcond))
-            return false;
-        else if (bprecond  && !ir_block_create_jump(end_bincrement, bprecond))
-            return false;
-        else if (bbody     && !ir_block_create_jump(end_bincrement, bbody))
-            return false;
-        else if              (!ir_block_create_jump(end_bincrement, bout))
+        if      (bpostcond)  tmpblock = bpostcond;
+        else if (bprecond)   tmpblock = bprecond;
+        else if (bbody)      tmpblock = bbody;
+        else                 tmpblock = bout;
+        if (!ir_block_create_jump(end_bincrement, tmpblock))
             return false;
     }
 
@@ -1135,5 +1138,13 @@ bool ast_loop_codegen(ast_loop *self, ast_function *func, bool lvalue, ir_value
             return false;
     }
 
+    /* Move 'bout' to the end */
+    if (!ir_function_blocks_remove(func->ir_func, bout_id) ||
+        !ir_function_blocks_add(func->ir_func, bout))
+    {
+        ir_block_delete(bout);
+        return false;
+    }
+
     return true;
 }