add relocation support

2 files changed, 31 insertions, 2 deletions

diff --git a/src/s2wasm.h b/src/s2wasm.h
index a1805e659..45f12fdb7 100644
--- a/src/s2wasm.h
+++ b/src/s2wasm.h
@@ -34,9 +34,13 @@ private:
 
   size_t nextStatic = 1; // location of next static allocation, i.e., the data segment
   std::map<Name, int32_t> staticAddresses; // name => address
+
   typedef std::pair<Const*, Name> Addressing;
   std::vector<Addressing> addressings; // we fix these up
 
+  typedef std::pair<std::vector<char>*, Name> Relocation; // the data, and the name whose address we should place there
+  std::vector<Relocation> relocations;
+
   // utilities
 
   void skipWhitespace() {
@@ -771,7 +775,12 @@ private:
       }
     } else if (match(".int32")) {
       raw->resize(4);
-      (*(int32_t*)(&(*raw)[0])) = getInt();
+      if (isdigit(*s)) {
+        (*(int32_t*)(&(*raw)[0])) = getInt();
+      } else {
+        // relocation, the address of something
+        relocations.emplace_back(raw, getStr());
+      }
     } else if (match(".int64")) {
       raw->resize(8);
       (*(int64_t*)(&(*raw)[0])) = getInt();
@@ -808,8 +817,12 @@ private:
       assert(curr->value.i32 > 0);
       curr->type = i32;
     }
+    for (auto& pair : relocations) {
+      auto raw = pair.first;
+      auto name = pair.second;
+      (*(int32_t*)(&(*raw)[0])) = staticAddresses[name];
+    }
   }
-
 };
 
 } // namespace wasm
diff --git a/test/dot_s/relocation.wast b/test/dot_s/relocation.wast
new file mode 100644
index 000000000..8949247bc
--- /dev/null
+++ b/test/dot_s/relocation.wast
@@ -0,0 +1,16 @@
+(module
+  (memory 0 4294967295 (segment 2 "\06\00\00\00") (segment 6 "\02\00\00\00"))
+  (export "main" $main)
+  (func $main (result i32)
+    (local $$0 i32)
+    (block $fake_return_waka123
+      (block
+        (br $fake_return_waka123
+          (i32.load align=4
+            (i32.const 0)
+          )
+        )
+      )
+    )
+  )
+)