Starting compiler work. Adding pass TODOs.

src/alloy/hir/instr.cc

@@ -9,5 +9,41 @@
 
 #include <alloy/hir/instr.h>
 
+#include <alloy/hir/block.h>
+
 using namespace alloy;
 using namespace alloy::hir;
+
+
+void Instr::set_src1(Value* value) {
+  if (src1.value == value) {
+    return;
+  }
+  if (src1.value) {
+    src1.value->RemoveUse(src1_use);
+  }
+  src1.value = value;
+  src1_use = value ? value->AddUse(block->arena, this) : NULL;
+}
+
+void Instr::set_src2(Value* value) {
+  if (src2.value == value) {
+    return;
+  }
+  if (src2.value) {
+    src2.value->RemoveUse(src2_use);
+  }
+  src2.value = value;
+  src2_use = value ? value->AddUse(block->arena, this) : NULL;
+}
+
+void Instr::set_src3(Value* value) {
+  if (src3.value == value) {
+    return;
+  }
+  if (src3.value) {
+    src3.value->RemoveUse(src3_use);
+  }
+  src3.value = value;
+  src3_use = value ? value->AddUse(block->arena, this) : NULL;
+}