[Object][Wasm] Use offset instead of index for Global address and store size

llvm/include/llvm/BinaryFormat/Wasm.h

@@ -350,6 +350,8 @@ struct WasmGlobal {
   WasmGlobalType Type;
   WasmInitExpr InitExpr;
   StringRef SymbolName; // from the "linking" section
+  uint32_t Offset; // Offset of the definition in the binary's Global section
+  uint32_t Size;   // Size of the definition in the binary's Global section
 };
 
 struct WasmTag {

llvm/include/llvm/Object/Wasm.h

@@ -239,7 +239,7 @@ class WasmObjectFile : public ObjectFile {
   bool isValidSectionSymbol(uint32_t Index) const;
   wasm::WasmFunction &getDefinedFunction(uint32_t Index);
   const wasm::WasmFunction &getDefinedFunction(uint32_t Index) const;
-  wasm::WasmGlobal &getDefinedGlobal(uint32_t Index);
+  const wasm::WasmGlobal &getDefinedGlobal(uint32_t Index) const;
   wasm::WasmTag &getDefinedTag(uint32_t Index);
 
   const WasmSection &getWasmSection(DataRefImpl Ref) const;

llvm/lib/Object/WasmObjectFile.cpp

@@ -1400,18 +1400,20 @@ Error WasmObjectFile::parseTagSection(ReadContext &Ctx) {
 
 Error WasmObjectFile::parseGlobalSection(ReadContext &Ctx) {
   GlobalSection = Sections.size();
+  const uint8_t *SectionStart = Ctx.Ptr;
   uint32_t Count = readVaruint32(Ctx);
   Globals.reserve(Count);
   while (Count--) {
     wasm::WasmGlobal Global;
     Global.Index = NumImportedGlobals + Globals.size();
+    const uint8_t *GlobalStart = Ctx.Ptr;
+    Global.Offset = static_cast<uint32_t>(GlobalStart - SectionStart);
     auto GlobalOpcode = readVaruint32(Ctx);
-    auto GlobalType = parseValType(Ctx, GlobalOpcode);
-    // assert(GlobalType <= std::numeric_limits<wasm::ValType>::max());
-    Global.Type.Type = (uint8_t)GlobalType;
+    Global.Type.Type = (uint8_t)parseValType(Ctx, GlobalOpcode);
     Global.Type.Mutable = readVaruint1(Ctx);
     if (Error Err = readInitExpr(Global.InitExpr, Ctx))
       return Err;
+    Global.Size = static_cast<uint32_t>(Ctx.Ptr - GlobalStart);
     Globals.push_back(Global);
   }
   if (Ctx.Ptr != Ctx.End)
@@ -1564,7 +1566,7 @@ WasmObjectFile::getDefinedFunction(uint32_t Index) const {
   return Functions[Index - NumImportedFunctions];
 }
 
-wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
+const wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) const {
   assert(isDefinedGlobalIndex(Index));
   return Globals[Index - NumImportedGlobals];
 }
@@ -1815,18 +1817,22 @@ Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
 
 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
   auto &Sym = getWasmSymbol(Symb);
+  if (!Sym.isDefined())
+    return 0;
+  Expected<section_iterator> Sec = getSymbolSection(Symb);
+  if (!Sec)
+    return Sec.takeError();
+  uint32_t SectionAddress = getSectionAddress(Sec.get()->getRawDataRefImpl());
   if (Sym.Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION &&
       isDefinedFunctionIndex(Sym.Info.ElementIndex)) {
-    // For object files, use the section offset. The linker relies on this.
-    // For linked files, use the file offset. This behavior matches the way
-    // browsers print stack traces and is useful for binary size analysis.
-    // (see https://webassembly.github.io/spec/web-api/index.html#conventions)
-    uint32_t Adjustment = isRelocatableObject() || isSharedObject()
-                              ? 0
-                              : Sections[CodeSection].Offset;
     return getDefinedFunction(Sym.Info.ElementIndex).CodeSectionOffset +
-           Adjustment;
+           SectionAddress;
   }
+  if (Sym.Info.Kind == wasm::WASM_SYMBOL_TYPE_GLOBAL &&
+      isDefinedGlobalIndex(Sym.Info.ElementIndex)) {
+    return getDefinedGlobal(Sym.Info.ElementIndex).Offset + SectionAddress;
+  }
+
   return getSymbolValue(Symb);
 }
 
@@ -1936,6 +1942,8 @@ uint32_t WasmObjectFile::getSymbolSize(SymbolRef Symb) const {
   const WasmSymbol &Sym = getWasmSymbol(Symb);
   if (!Sym.isDefined())
     return 0;
+  if (Sym.isTypeGlobal())
+    return getDefinedGlobal(Sym.Info.ElementIndex).Size;
   if (Sym.isTypeData())
     return Sym.Info.DataRef.Size;
   if (Sym.isTypeFunction())

llvm/test/tools/llvm-nm/wasm/exports.yaml

@@ -64,4 +64,4 @@ Sections:
 
 # CHECK:      00000000 D dexport
 # CHECK-NEXT: 00000001 T fexport
-# CHECK-NEXT: 00000000 D gexport
+# CHECK-NEXT: 00000001 D gexport

llvm/test/tools/llvm-nm/wasm/weak-symbols.yaml

@@ -80,6 +80,6 @@ Sections:
 
 # CHECK:      00000000 W weak_defined_data
 # CHECK-NEXT: 00000001 W weak_defined_func
-# CHECK-NEXT: 00000000 W weak_defined_global
+# CHECK-NEXT: 00000001 W weak_defined_global
 # CHECK-NEXT:          w weak_import_data
 # CHECK-NEXT:          w weak_import_func

llvm/test/tools/llvm-objdump/wasm/linked-symbol-table-namesec.yaml

@@ -3,10 +3,11 @@
 #
 # CHECK:      SYMBOL TABLE:
 # CHECK-NEXT: 00000000   F *UND* 00000000 my_func_import_name
-# CHECK-NEXT: 00000083 g F CODE 00000003 my_func_export_name
-# CHECK-NEXT: 00000086 l F CODE 00000003 my_func_local_name
+# CHECK-NEXT: 0000008c g F CODE 00000003 my_func_export_name
+# CHECK-NEXT: 0000008f l F CODE 00000003 my_func_local_name
 # CHECK-NEXT: 00000000    *UND* 00000000 my_global_import_name
-# CHECK-NEXT: 00000001 g  GLOBAL 00000000 my_global_export_name
+# CHECK-NEXT: 0000004c g  GLOBAL 00000005 my_global_export_name
+# CHECK-NEXT: 00000051 g  GLOBAL 00000009 my_global_local_name
 # CHECK-NEXT: 00000000 l O DATA 00000004 my_datasegment_name
 
 --- !WASM
@@ -44,6 +45,12 @@ Sections:
         InitExpr:
           Opcode:          I32_CONST
           Value:           42
+      - Index:           2
+        Mutable:         true
+        Type:            I64
+        InitExpr:
+          Opcode:          I64_CONST
+          Value:           5000000000
   - Type:            EXPORT
     Exports:
       - Name:            my_func_export
@@ -82,6 +89,8 @@ Sections:
        Name:         my_global_import_name
      - Index:        1
        Name:         my_global_export_name
+     - Index:        2
+       Name:         my_global_local_name
     DataSegmentNames:
      - Index:        0
        Name:         my_datasegment_name