Fully handle EM_ASM in s2wasm (#910)

* Fully handle EM_ASM in s2wasm

* Iterate with size_ts, remember to erase from importsMap as well

* Fix dot_s test EM_ASM signatures

* Move Name out to its own file, support/name.h

* Move removeImportsWithSubstring out of Module class

5 files changed, 83 insertions, 29 deletions

diff --git a/src/shell-interface.h b/src/shell-interface.h
index ee7ba4d9c..26e0c1742 100644
--- a/src/shell-interface.h
+++ b/src/shell-interface.h
@@ -23,6 +23,7 @@
 
 #include "shared-constants.h"
 #include "asmjs/shared-constants.h"
+#include "support/name.h"
 #include "wasm.h"
 #include "wasm-interpreter.h"
 
diff --git a/src/support/name.h b/src/support/name.h
new file mode 100644
index 000000000..9853f5462
--- /dev/null
+++ b/src/support/name.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * 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.
+ */
+
+#ifndef wasm_support_string_h
+#define wasm_support_string_h
+
+#include <cstring>
+
+#include "emscripten-optimizer/istring.h"
+
+namespace wasm {
+
+// We use a Name for all of the identifiers. These are IStrings, so they are
+// all interned - comparisons etc are just pointer comparisons, so there is no
+// perf loss. Having names everywhere makes using the AST much nicer (for
+// example, block names are strings and not offsets, which makes composition
+// - adding blocks, removing blocks - easy). One exception is local variables,
+// where we do use indices, as they are a large proportion of the AST,
+// perf matters a lot there, and compositionality is not a problem.
+// TODO: as an optimization, IString values < some threshold could be considered
+//       numerical indices directly.
+
+struct Name : public cashew::IString {
+  Name() : cashew::IString() {}
+  Name(const char* str) : cashew::IString(str, false) {}
+  Name(cashew::IString str) : cashew::IString(str) {}
+  Name(const std::string& str) : cashew::IString(str.c_str(), false) {}
+
+  friend std::ostream& operator<<(std::ostream& o, Name name) {
+    assert(name.str);
+    return o << '$' << name.str; // reference interpreter requires we prefix all names
+  }
+
+  static Name fromInt(size_t i) {
+    return cashew::IString(std::to_string(i).c_str(), false);
+  }
+
+  bool hasSubstring(cashew::IString substring) {
+    return strstr(c_str(), substring.c_str()) != nullptr;
+  }
+};
+
+} // namespace wasm
+
+#endif // wasm_support_string_h
diff --git a/src/wasm-emscripten.cpp b/src/wasm-emscripten.cpp
index e8f0194d3..99115fae9 100644
--- a/src/wasm-emscripten.cpp
+++ b/src/wasm-emscripten.cpp
@@ -57,8 +57,20 @@ static bool hasI64ResultOrParam(FunctionType* ft) {
   return false;
 }
 
+void removeImportsWithSubstring(Module& module, Name name) {
+  std::vector<Name> toRemove;
+  for (auto& import : module.imports) {
+    if (import->name.hasSubstring(name)) {
+      toRemove.push_back(import->name);
+    }
+  }
+  for (auto importName : toRemove) {
+    module.removeImport(importName);
+  }
+}
+
 std::vector<Function*> makeDynCallThunks(Module& wasm, std::vector<Name> const& tableSegmentData) {
-  wasm.removeImport(EMSCRIPTEN_ASM_CONST); // we create _sig versions
+  removeImportsWithSubstring(wasm, EMSCRIPTEN_ASM_CONST); // we create _sig versions
 
   std::vector<Function*> generatedFunctions;
   std::unordered_set<std::string> sigs;
@@ -103,7 +115,7 @@ struct AsmConstWalker : public PostWalker<AsmConstWalker, Visitor<AsmConstWalker
 };
 
 void AsmConstWalker::visitCallImport(CallImport* curr) {
-  if (curr->target == EMSCRIPTEN_ASM_CONST) {
+  if (curr->target.hasSubstring(EMSCRIPTEN_ASM_CONST)) {
     auto arg = curr->operands[0]->cast<Const>();
     auto address = arg->value.geti32();
     auto segmentIterator = segmentsByAddress.find(address);
@@ -122,7 +134,14 @@ void AsmConstWalker::visitCallImport(CallImport* curr) {
     } else {
       id = ids[code];
     }
-    std::string sig = getSig(curr);
+    std::string baseSig = getSig(curr);
+    std::string sig = "";
+    for (size_t i = 0; i < baseSig.size(); ++i) {
+      // Omit the signature of the "code" parameter, taken as a string, as the first argument
+      if (i != 1) {
+        sig += baseSig[i];
+      }
+    }
     sigsForCode[code].insert(sig);
     std::string fixedTarget = EMSCRIPTEN_ASM_CONST.str + std::string("_") + sig;
     curr->target = cashew::IString(fixedTarget.c_str(), false);
diff --git a/src/wasm-linker.h b/src/wasm-linker.h
index 608576190..663bb9e78 100644
--- a/src/wasm-linker.h
+++ b/src/wasm-linker.h
@@ -25,6 +25,7 @@
 #define WASM_WASM_LINK_H
 
 #include "support/archive.h"
+#include "support/name.h"
 #include "support/utilities.h"
 #include "wasm.h"
 
diff --git a/src/wasm.h b/src/wasm.h
index 4ad0870cc..21f7b420e 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -58,36 +58,11 @@
 #include "mixed_arena.h"
 #include "pretty_printing.h"
 #include "support/bits.h"
+#include "support/name.h"
 #include "support/utilities.h"
 
 namespace wasm {
 
-// We use a Name for all of the identifiers. These are IStrings, so they are
-// all interned - comparisons etc are just pointer comparisons, so there is no
-// perf loss. Having names everywhere makes using the AST much nicer (for
-// example, block names are strings and not offsets, which makes composition
-// - adding blocks, removing blocks - easy). One exception is local variables,
-// where we do use indices, as they are a large proportion of the AST,
-// perf matters a lot there, and compositionality is not a problem.
-// TODO: as an optimization, IString values < some threshold could be considered
-//       numerical indices directly.
-
-struct Name : public cashew::IString {
-  Name() : cashew::IString() {}
-  Name(const char* str) : cashew::IString(str, false) {}
-  Name(cashew::IString str) : cashew::IString(str) {}
-  Name(const std::string& str) : cashew::IString(str.c_str(), false) {}
-
-  friend std::ostream& operator<<(std::ostream& o, Name name) {
-    assert(name.str);
-    return o << '$' << name.str; // reference interpreter requires we prefix all names
-  }
-
-  static Name fromInt(size_t i) {
-    return cashew::IString(std::to_string(i).c_str(), false);
-  }
-};
-
 // An index in a wasm module
 typedef uint32_t Index;