From 57a9e77add02dc1d874fdbfee2c61cae8c0eefa1 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Wed, 9 Dec 2020 20:54:18 -0800
Subject: Read and write data segments names in names section (#3435)

---
 src/wasm/wasm-binary.cpp | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

(limited to 'src/wasm/wasm-binary.cpp')

diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 314364f38..6d4689056 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -690,7 +690,31 @@ void WasmBinaryWriter::writeNames() {
     }
   }
 
-  // TODO: label, type, element and data names
+  // memory names
+  if (wasm->memory.exists) {
+    Index count = 0;
+    for (auto& seg : wasm->memory.segments) {
+      if (seg.name.is()) {
+        count++;
+      }
+    }
+
+    if (count) {
+      auto substart =
+        startSubsection(BinaryConsts::UserSections::Subsection::NameData);
+      o << U32LEB(count);
+      for (Index i = 0; i < wasm->memory.segments.size(); i++) {
+        auto& seg = wasm->memory.segments[i];
+        if (seg.name.is()) {
+          o << U32LEB(i);
+          writeEscapedName(seg.name.str);
+        }
+      }
+      finishSubsection(substart);
+    }
+  }
+
+  // TODO: label, type, and element names
   // see: https://github.com/WebAssembly/extended-name-section
 
   finishSection(start);
@@ -2566,6 +2590,20 @@ void WasmBinaryBuilder::readNames(size_t payloadLen) {
                     << std::to_string(index) << std::endl;
         }
       }
+    } else if (nameType == BinaryConsts::UserSections::Subsection::NameData) {
+      auto num = getU32LEB();
+      for (size_t i = 0; i < num; i++) {
+        auto index = getU32LEB();
+        auto rawName = getInlineString();
+        if (index < wasm.memory.segments.size()) {
+          wasm.memory.segments[i].name = rawName;
+        } else {
+          std::cerr << "warning: memory index out of bounds in name section, "
+                       "memory subsection: "
+                    << std::string(rawName.str) << " at index "
+                    << std::to_string(index) << std::endl;
+        }
+      }
     } else if (nameType == BinaryConsts::UserSections::Subsection::NameGlobal) {
       auto num = getU32LEB();
       std::set<Name> usedNames;
-- 
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