ir: sort insertions, add file for register-allocation

Author: bvdberg

ir/context.c2

@@ -741,6 +741,12 @@ fn void Context.finalizeFunction(Context* c, SymbolId id) {
 
     t.removeNone(fi2);
     if (print) c.print_function(symbol, fi2, "after remove none");
+
+    t.allocateRegisters(fi2);
+
+    // leave SSA (eliminate Phis)
+    // generate Instruction
+    // ..
 }
 
 fn bool empty_block(const Block* b, const InstrList* instructions) {

ir/instr_inserter.c2

@@ -63,9 +63,15 @@ public fn void InstrInserter.free(InstrInserter* ii) {
 public fn void InstrInserter.add(InstrInserter* ii, u32 location, u32 instr_idx) {
     if (ii.count == ii.capacity) ii.resize(ii.capacity * 2);
 
-    InstrInsertion* ins = &ii.ins[ii.count++];
-    ins.location = location;
-    ins.instr_idx = instr_idx;
+    u32 idx = ii.count;
+    while (idx > 0) {
+        if (ii.ins[idx-1].location <= location) break;
+        ii.ins[idx] = ii.ins[idx-1];
+        idx--;
+    }
+    ii.ins[idx].location = location;
+    ii.ins[idx].instr_idx = instr_idx;
+    ii.count++;
 }
 
 public fn void InstrInserter.start(InstrInserter* ii) {
@@ -87,7 +93,7 @@ public fn bool InstrInserter.needsFixup(const InstrInserter* ii) {
     return ii.count != 0;
 }
 
-fn void InstrInserter.dump(const InstrInserter* ii) @(unused) {
+public fn void InstrInserter.dump(const InstrInserter* ii) @(unused) {
     printf("Insertions:\n");
     for (u32 i=0; i<ii.count; i++) {
         const InstrInsertion* ins = &ii.ins[i];

ir/print.c2

@@ -31,7 +31,8 @@ const char* col_Symbol = color.Bblue;
 const char* col_Attr = color.Bmagenta;
 const char* col_Unknown = color.Yellow;
 const char* col_Value = color.Magenta;
-const char* col_Data = color.Bcyan;
+const char* col_Register = color.Cyan;
+const char* col_Data = color.Bgreen;
 const char* col_Slot = color.Bcyan;
 const char* col_Temp = color.Bgreen;
 const char* col_Param = color.Cyan;
@@ -512,9 +513,12 @@ fn void PrintHelper.printRef(PrintHelper* ph, Ref r, bool print_type) {
         out.color(col_Block);
         out.add(ph.c.pool.idx2str(r.value));
         break;
+    case Register:
+        out.color(col_Register);
+        out.print("R%d", r.value);
+        break;
     }
     out.color(color.Normal);
-
 }
 
 

ir/ref.c2

@@ -30,6 +30,7 @@ public type RefKind enum u8 {
     Float,     // constant_idx
     Double,    // constant_idx
     Text,      // idx into string pool, for comment
+    Register,  // nr (0,1,..)
 }
 
 fn const char* RefKind.str(RefKind k) {
@@ -46,6 +47,7 @@ fn const char* RefKind.str(RefKind k) {
     case Float:     return "float";
     case Double:    return "double";
     case Text:      return "text";
+    case Register:  return "register";
     }
     return nil;
 }

ir/register_alloc.c2

@@ -0,0 +1,29 @@
+/* Copyright 2022-2025 Bas van den Berg
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+module ir;
+
+//import stdlib;
+//import string;
+//import stdio local;
+
+fn void Tools.allocateRegisters(Tools* t, FunctionInfo* fi) {
+    // Need to know:
+    // how many registers available
+    // locations of params (%1, %2, etc)
+    // or just assign virtual regs: R0, R1?
+    // also need to know return register?
+}
+

ir_examples/bitfield_init.c2

@@ -11,7 +11,6 @@ const Design[] Designs = {
     { .stackable=1, .rarity=5, .bla=12345 },
     { .rarity=5, .stackable=1, .bla=12345 },
     { .bla=12345, .rarity=5, .stackable=1 },
-    { 12345, 1, 6, 5, },    // error
 }
 
 public fn i32 main() {

recipe.txt

@@ -285,6 +285,7 @@ executable c2c
     ir/instr.c2
     ir/instr_inserter.c2
     ir/instr_kind.c2
+    ir/register_alloc.c2
     ir/slot_collector.c2
     ir/ssa.c2
     ir/symbol_list.c2