[WebAssembly] Remove DataSize from linking metadata

This means we don't need to write the linking metadata section
at all for executable (non-relocatable) output.

Differential Revision: https://reviews.llvm.org/D42869

llvm-svn: 326268

1 files changed, 9 insertions, 16 deletions

diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 2d9a9d95fa2..90252b71fe0 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -117,7 +117,6 @@ private:
   void writeSections();
 
   uint64_t FileSize = 0;
-  uint32_t DataSize = 0;
   uint32_t NumMemoryPages = 0;
 
   std::vector<const WasmSignature *> Types;
@@ -386,11 +385,6 @@ void Writer::createLinkingSection() {
       createSyntheticSection(WASM_SEC_CUSTOM, "linking");
   raw_ostream &OS = Section->getStream();
 
-  SubSection DataSizeSubSection(WASM_DATA_SIZE);
-  writeUleb128(DataSizeSubSection.getStream(), DataSize, "data size");
-  DataSizeSubSection.finalizeContents();
-  DataSizeSubSection.writeToStream(OS);
-
   if (!Config->Relocatable)
     return;
 
@@ -550,10 +544,8 @@ void Writer::writeSections() {
 //  - heap start / unallocated
 void Writer::layoutMemory() {
   uint32_t MemoryPtr = 0;
-  if (!Config->Relocatable) {
-    MemoryPtr = Config->GlobalBase;
-    debugPrint("mem: global base = %d\n", Config->GlobalBase);
-  }
+  MemoryPtr = Config->GlobalBase;
+  debugPrint("mem: global base = %d\n", Config->GlobalBase);
 
   createOutputSegments();
 
@@ -574,10 +566,7 @@ void Writer::layoutMemory() {
   if (WasmSym::DataEnd)
     WasmSym::DataEnd->setVirtualAddress(MemoryPtr);
 
-  DataSize = MemoryPtr;
-  if (!Config->Relocatable)
-    DataSize -= Config->GlobalBase;
-  debugPrint("mem: static data = %d\n", DataSize);
+  debugPrint("mem: static data = %d\n", MemoryPtr - Config->GlobalBase);
 
   // Stack comes after static data and bss
   if (!Config->Relocatable) {
@@ -624,9 +613,10 @@ void Writer::createSections() {
   createDataSection();
 
   // Custom sections
-  if (Config->Relocatable)
+  if (Config->Relocatable) {
     createRelocSections();
-  createLinkingSection();
+    createLinkingSection();
+  }
   if (!Config->StripDebug && !Config->StripAll)
     createNameSection();
 
@@ -919,6 +909,9 @@ void Writer::calculateInitFunctions() {
 }
 
 void Writer::run() {
+  if (Config->Relocatable)
+    Config->GlobalBase = 0;
+
   log("-- calculateImports");
   calculateImports();
   log("-- assignIndexes");