[llvm] r353360 - [WebAssembly] Add symbol flag to the binary format llvm.used

Sam Clegg via llvm-commits llvm-commits at lists.llvm.org
Wed Feb 6 17:24:44 PST 2019


Author: sbc
Date: Wed Feb  6 17:24:44 2019
New Revision: 353360

URL: http://llvm.org/viewvc/llvm-project?rev=353360&view=rev
Log:
[WebAssembly] Add symbol flag to the binary format llvm.used

Summary:
Rather than add a new attribute
See https://github.com/WebAssembly/tool-conventions/issues/64

Subscribers: dschuff, jgravelle-google, aheejin, sunfish, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57864

Added:
    llvm/trunk/test/MC/WebAssembly/no-dead-strip.ll
Modified:
    llvm/trunk/include/llvm/BinaryFormat/Wasm.h
    llvm/trunk/include/llvm/MC/MCSymbolWasm.h
    llvm/trunk/lib/MC/MCAsmInfoWasm.cpp
    llvm/trunk/lib/MC/MCWasmStreamer.cpp
    llvm/trunk/lib/MC/WasmObjectWriter.cpp
    llvm/trunk/lib/ObjectYAML/WasmYAML.cpp
    llvm/trunk/tools/llvm-readobj/WasmDumper.cpp

Modified: llvm/trunk/include/llvm/BinaryFormat/Wasm.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/BinaryFormat/Wasm.h?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/include/llvm/BinaryFormat/Wasm.h (original)
+++ llvm/trunk/include/llvm/BinaryFormat/Wasm.h Wed Feb  6 17:24:44 2019
@@ -289,6 +289,7 @@ const unsigned WASM_SYMBOL_BINDING_LOCAL
 const unsigned WASM_SYMBOL_VISIBILITY_DEFAULT = 0x0;
 const unsigned WASM_SYMBOL_VISIBILITY_HIDDEN = 0x4;
 const unsigned WASM_SYMBOL_UNDEFINED = 0x10;
+const unsigned WASM_SYMBOL_EXPORTED = 0x20;
 
 #define WASM_RELOC(name, value) name = value,
 

Modified: llvm/trunk/include/llvm/MC/MCSymbolWasm.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCSymbolWasm.h?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCSymbolWasm.h (original)
+++ llvm/trunk/include/llvm/MC/MCSymbolWasm.h Wed Feb  6 17:24:44 2019
@@ -46,6 +46,13 @@ public:
   wasm::WasmSymbolType getType() const { return Type; }
   void setType(wasm::WasmSymbolType type) { Type = type; }
 
+  bool isExported() const {
+    return getFlags() & wasm::WASM_SYMBOL_EXPORTED;
+  }
+  void setExported() const {
+    modifyFlags(wasm::WASM_SYMBOL_EXPORTED, wasm::WASM_SYMBOL_EXPORTED);
+  }
+
   bool isWeak() const { return IsWeak; }
   void setWeak(bool isWeak) { IsWeak = isWeak; }
 

Modified: llvm/trunk/lib/MC/MCAsmInfoWasm.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmInfoWasm.cpp?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAsmInfoWasm.cpp (original)
+++ llvm/trunk/lib/MC/MCAsmInfoWasm.cpp Wed Feb  6 17:24:44 2019
@@ -18,6 +18,7 @@ void MCAsmInfoWasm::anchor() {}
 
 MCAsmInfoWasm::MCAsmInfoWasm() {
   HasIdentDirective = true;
+  HasNoDeadStrip = true;
   WeakRefDirective = "\t.weak\t";
   PrivateGlobalPrefix = ".L";
   PrivateLabelPrefix = ".L";

Modified: llvm/trunk/lib/MC/MCWasmStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCWasmStreamer.cpp?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCWasmStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCWasmStreamer.cpp Wed Feb  6 17:24:44 2019
@@ -121,6 +121,10 @@ bool MCWasmStreamer::EmitSymbolAttribute
   case MCSA_Cold:
     break;
 
+  case MCSA_NoDeadStrip:
+    Symbol->setExported();
+    break;
+
   default:
     // unrecognized directive
     llvm_unreachable("unexpected MCSymbolAttr");

Modified: llvm/trunk/lib/MC/WasmObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WasmObjectWriter.cpp?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WasmObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WasmObjectWriter.cpp Wed Feb  6 17:24:44 2019
@@ -1454,6 +1454,8 @@ uint64_t WasmObjectWriter::writeObject(M
       Flags |= wasm::WASM_SYMBOL_BINDING_LOCAL;
     if (WS.isUndefined())
       Flags |= wasm::WASM_SYMBOL_UNDEFINED;
+    if (WS.isExported())
+      Flags |= wasm::WASM_SYMBOL_EXPORTED;
 
     wasm::WasmSymbolInfo Info;
     Info.Name = WS.getName();

Modified: llvm/trunk/lib/ObjectYAML/WasmYAML.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ObjectYAML/WasmYAML.cpp?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/lib/ObjectYAML/WasmYAML.cpp (original)
+++ llvm/trunk/lib/ObjectYAML/WasmYAML.cpp Wed Feb  6 17:24:44 2019
@@ -486,6 +486,7 @@ void ScalarBitSetTraits<WasmYAML::Symbol
   // BCaseMask(VISIBILITY_MASK, VISIBILITY_DEFAULT);
   BCaseMask(VISIBILITY_MASK, VISIBILITY_HIDDEN);
   BCaseMask(UNDEFINED, UNDEFINED);
+  BCaseMask(EXPORTED, EXPORTED);
 #undef BCaseMask
 }
 

Added: llvm/trunk/test/MC/WebAssembly/no-dead-strip.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/no-dead-strip.ll?rev=353360&view=auto
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/no-dead-strip.ll (added)
+++ llvm/trunk/test/MC/WebAssembly/no-dead-strip.ll Wed Feb  6 17:24:44 2019
@@ -0,0 +1,21 @@
+; RUN: llc -filetype=obj -wasm-keep-registers %s -o - | llvm-readobj --symbols | FileCheck %s
+
+target triple = "wasm32-unknown-unknown"
+
+ at llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @foo to i8*)], section "llvm.metadata"
+
+define i32 @foo() {
+entry:
+    ret i32 0
+}
+
+; CHECK:      Symbols [
+; CHECK-NEXT:   Symbol {
+; CHECK-NEXT:     Name: foo
+; CHECK-NEXT:     Type: FUNCTION (0x0)
+; CHECK-NEXT:     Flags [ (0x20)
+; CHECK-NEXT:       EXPORTED (0x20)
+; CHECK-NEXT:     ]
+; CHECK-NEXT:     ElementIndex: 0x0
+; CHECK-NEXT:   }
+; CHECK-NEXT: ]

Modified: llvm/trunk/tools/llvm-readobj/WasmDumper.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/WasmDumper.cpp?rev=353360&r1=353359&r2=353360&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-readobj/WasmDumper.cpp (original)
+++ llvm/trunk/tools/llvm-readobj/WasmDumper.cpp Wed Feb  6 17:24:44 2019
@@ -49,6 +49,7 @@ static const EnumEntry<unsigned> WasmSym
   ENUM_ENTRY(VISIBILITY_DEFAULT),
   ENUM_ENTRY(VISIBILITY_HIDDEN),
   ENUM_ENTRY(UNDEFINED),
+  ENUM_ENTRY(EXPORTED),
 #undef ENUM_ENTRY
 };
 




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