commit da84b688f9160bcd00ef46932e752aa33af94bc7
author Dan Gohman <dan433584@gmail.com> Thu Aug 29 22:40:00 2019 +0000
committer Dan Gohman <dan433584@gmail.com> Thu Aug 29 22:40:00 2019 +0000
tree 0b4589181fa40626e1847fbd32a29e1c174dd182
parent 452e5647a5862599a679cf892777ff1ea45a6462

[WebAssembly] Make __attribute__((used)) not imply export.

Add an WASM_SYMBOL_NO_STRIP flag, so that __attribute__((used)) doesn't
need to imply exporting. When targeting Emscripten, have
WASM_SYMBOL_NO_STRIP imply exporting.

Differential Revision: https://reviews.llvm.org/D62542

llvm-svn: 370415

llvm/lib/MC/MCWasmObjectTargetWriter.cpp

diff --git a/llvm/lib/MC/MCWasmObjectTargetWriter.cpp b/llvm/lib/MC/MCWasmObjectTargetWriter.cpp
index e462578..1ccb3a5 100644
--- a/llvm/lib/MC/MCWasmObjectTargetWriter.cpp
+++ b/llvm/lib/MC/MCWasmObjectTargetWriter.cpp
@@ -10,8 +10,9 @@
 
 using namespace llvm;
 
-MCWasmObjectTargetWriter::MCWasmObjectTargetWriter(bool Is64Bit)
-    : Is64Bit(Is64Bit) {}
+MCWasmObjectTargetWriter::MCWasmObjectTargetWriter(bool Is64Bit,
+                                                   bool IsEmscripten)
+    : Is64Bit(Is64Bit), IsEmscripten(IsEmscripten) {}
 
 // Pin the vtable to this object file
 MCWasmObjectTargetWriter::~MCWasmObjectTargetWriter() = default;

llvm/lib/MC/MCWasmStreamer.cpp

diff --git a/llvm/lib/MC/MCWasmStreamer.cpp b/llvm/lib/MC/MCWasmStreamer.cpp
index 86fa721..e7e96ec 100644
--- a/llvm/lib/MC/MCWasmStreamer.cpp
+++ b/llvm/lib/MC/MCWasmStreamer.cpp
@@ -122,7 +122,7 @@
     break;
 
   case MCSA_NoDeadStrip:
-    Symbol->setExported();
+    Symbol->setNoStrip();
     break;
 
   default:

llvm/lib/MC/WasmObjectWriter.cpp

diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index cb00241..5361888 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -258,6 +258,7 @@
 
   // TargetObjectWriter wrappers.
   bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
+  bool isEmscripten() const { return TargetObjectWriter->isEmscripten(); }
 
   void startSection(SectionBookkeeping &Section, unsigned SectionId);
   void startCustomSection(SectionBookkeeping &Section, StringRef Name);
@@ -1443,8 +1444,12 @@
       Flags |= wasm::WASM_SYMBOL_BINDING_LOCAL;
     if (WS.isUndefined())
       Flags |= wasm::WASM_SYMBOL_UNDEFINED;
-    if (WS.isExported())
-      Flags |= wasm::WASM_SYMBOL_EXPORTED;
+    if (WS.isNoStrip()) {
+      Flags |= wasm::WASM_SYMBOL_NO_STRIP;
+      if (isEmscripten()) {
+        Flags |= wasm::WASM_SYMBOL_EXPORTED;
+      }
+    }
     if (WS.getName() != WS.getImportName())
       Flags |= wasm::WASM_SYMBOL_EXPLICIT_NAME;