[WebAssembly] Remove WASM_STACK_POINTER.

WASM_STACK_POINTER and the .stack_pointer directive are no longer needed
now that the stack pointer global is an import.

llvm-svn: 319956

1 files changed, 4 insertions, 35 deletions

diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 0e93eb835c0..351927d628a 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -287,8 +287,7 @@ private:
   void writeDataRelocSection();
   void writeLinkingMetaDataSection(
       ArrayRef<WasmDataSegment> Segments, uint32_t DataSize,
-      SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags,
-      Optional<uint32_t> StackPointerGlobal);
+      SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags);
 
   uint32_t getProvisionalValue(const WasmRelocationEntry &RelEntry);
   void applyRelocations(ArrayRef<WasmRelocationEntry> Relocations,
@@ -929,18 +928,11 @@ void WasmObjectWriter::writeDataRelocSection() {
 
 void WasmObjectWriter::writeLinkingMetaDataSection(
     ArrayRef<WasmDataSegment> Segments, uint32_t DataSize,
-    SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags,
-    Optional<uint32_t> StackPointerGlobal) {
+    SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags) {
   SectionBookkeeping Section;
   startSection(Section, wasm::WASM_SEC_CUSTOM, "linking");
   SectionBookkeeping SubSection;
 
-  if (StackPointerGlobal.hasValue()) {
-    startSection(SubSection, wasm::WASM_STACK_POINTER);
-    encodeULEB128(StackPointerGlobal.getValue(), getStream()); // id
-    endSection(SubSection);
-  }
-
   if (SymbolFlags.size() != 0) {
     startSection(SubSection, wasm::WASM_SYMBOL_INFO);
     encodeULEB128(SymbolFlags.size(), getStream());
@@ -1011,8 +1003,6 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
   SmallPtrSet<const MCSymbolWasm *, 4> IsAddressTaken;
   unsigned NumFuncImports = 0;
   SmallVector<WasmDataSegment, 4> DataSegments;
-  Optional<StringRef> StackPointerGlobalName;
-  Optional<uint32_t> StackPointerGlobal;
   uint32_t DataSize = 0;
 
   // Populate the IsAddressTaken set.
@@ -1095,23 +1085,6 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
     }
   }
 
-  // In the special .stack_pointer section, we've encoded the stack pointer
-  // index.
-  MCSectionWasm *StackPtr =
-      Ctx.getWasmSection(".stack_pointer", SectionKind::getMetadata());
-  if (!StackPtr->getFragmentList().empty()) {
-    if (StackPtr->getFragmentList().size() != 1)
-      report_fatal_error("only one .stack_pointer fragment supported");
-    const MCFragment &Frag = *StackPtr->begin();
-    if (Frag.hasInstructions() || Frag.getKind() != MCFragment::FT_Data)
-      report_fatal_error("only data supported in .stack_pointer");
-    const auto &DataFrag = cast<MCDataFragment>(Frag);
-    if (!DataFrag.getFixups().empty())
-      report_fatal_error("fixups not supported in .stack_pointer");
-    const SmallVectorImpl<char> &Contents = DataFrag.getContents();
-    StackPointerGlobalName = StringRef(Contents.data(), Contents.size());
-  }
-
   // Populate FunctionTypeIndices and Imports.
   for (const MCSymbol &S : Asm.symbols()) {
     const auto &WS = static_cast<const MCSymbolWasm &>(S);
@@ -1144,11 +1117,8 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
 
         // If this global is the stack pointer, make it mutable and remember it
         // so that we can emit metadata for it.
-        if (StackPointerGlobalName.hasValue() &&
-            WS.getName() == StackPointerGlobalName.getValue()) {
+        if (WS.getName() == "__stack_pointer")
           Import.IsMutable = true;
-          StackPointerGlobal = NumGlobalImports;
-        }
 
         ++NumGlobalImports;
       }
@@ -1338,8 +1308,7 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
   writeNameSection(Functions, Imports, NumFuncImports);
   writeCodeRelocSection();
   writeDataRelocSection();
-  writeLinkingMetaDataSection(DataSegments, DataSize, SymbolFlags,
-                              StackPointerGlobal);
+  writeLinkingMetaDataSection(DataSegments, DataSize, SymbolFlags);
 
   // TODO: Translate the .comment section to the output.
   // TODO: Translate debug sections to the output.