[WebAssembly] Added visibility and ident directives to WasmAsmParser.

[aardappel]

Summary

These are output by clang -S, so can now be roundtripped thru clang.

(partially) fixes: https://bugs.llvm.org/show_bug.cgi?id=34544

[aardappel]

Reviewers: the code parsing these directives is from ELFAsmParser. We decided in the past that WASM should have its own container format parser, since it is a very different format from ELF, but copying code is never fun. Any suggestions here? Inherit from ELFAsmParser or take it as a member (may have unintended consequences). Pull into new base class for both (ELF people may not be happy with that). Or just ignore it?

[dschuff]

lib/MC/MCParser/WasmAsmParser.cpp

231

@sbc100 do we support exactly the same set of visibility types as ELF? I think the answer is no, right? In that case it probably also answers the question of whether we can share code with ELF too.

[sbc100]

I'm sad to see more code duplication but OK with adding along with the TODO to find a better way.

lib/MC/MCParser/WasmAsmParser.cpp

231

Technically we don't support "protected" yet, but there is no reason why we shouldn't in the future. Even though we don't support it its not clear to me if we should generate an error here, or perhaps in EmitSymbolAttribute?

[sbc100]

test/MC/WebAssembly/basic-assembly.s

91

Align second column with line above?

178

Indentation looks great than directives below?

[aardappel]

lib/MC/MCParser/WasmAsmParser.cpp

231

I will comment out "protected" for now, which will make it error.

test/MC/WebAssembly/basic-assembly.s

91

File had mixed tabs and spaces, which makes it look different in code review.. removing tabs.

178

I'll make indentation in this file more consistent..

[aardappel]

Removed "protected" and fixed indentation in tests.

lib/MC/MCParser/WasmAsmParser.cpp

void Initialize(MCAsmParser &P) override {
     Lexer = &Parser->getLexer();
     // Call the base implementation.
     this->MCAsmParserExtension::Initialize(*Parser);
 
     addDirectiveHandler<&WasmAsmParser::parseSectionDirectiveText>(".text");
     addDirectiveHandler<&WasmAsmParser::parseSectionDirective>(".section");
     addDirectiveHandler<&WasmAsmParser::parseDirectiveSize>(".size");
     addDirectiveHandler<&WasmAsmParser::parseDirectiveType>(".type");
+    addDirectiveHandler<&WasmAsmParser::ParseDirectiveIdent>(".ident");
+    addDirectiveHandler<
+      &WasmAsmParser::ParseDirectiveSymbolAttribute>(".weak");
+    addDirectiveHandler<
+      &WasmAsmParser::ParseDirectiveSymbolAttribute>(".local");
+    addDirectiveHandler<
+      &WasmAsmParser::ParseDirectiveSymbolAttribute>(".internal");
+    addDirectiveHandler<
+      &WasmAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
   }
 
   bool error(const StringRef &Msg, const AsmToken &Tok) {
     return Parser->Error(Tok.getLoc(), Msg + Tok.getString());
   }
 
   bool isNext(AsmToken::TokenKind Kind) {
     auto Ok = Lexer->is(Kind);
if (TypeName == "function")
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
     else if (TypeName == "global")
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
     else
       return error("Unknown WASM symbol type: ", Lexer->getTok());
     Lex();
     return expect(AsmToken::EndOfStatement, "EOL");
   }
+
+  // FIXME: Shared with ELF.
+  /// ParseDirectiveIdent
+  ///  ::= .ident string
+  bool ParseDirectiveIdent(StringRef, SMLoc) {
+    if (getLexer().isNot(AsmToken::String))
+      return TokError("unexpected token in '.ident' directive");
+    StringRef Data = getTok().getIdentifier();
+    Lex();
+    if (getLexer().isNot(AsmToken::EndOfStatement))
+      return TokError("unexpected token in '.ident' directive");
+    Lex();
+    getStreamer().EmitIdent(Data);
+    return false;
+  }
+
+  // FIXME: Shared with ELF.
+  /// ParseDirectiveSymbolAttribute
+  ///  ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
+  bool ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
+    MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
+      .Case(".weak", MCSA_Weak)
+      .Case(".local", MCSA_Local)
+      .Case(".hidden", MCSA_Hidden)
+      .Case(".internal", MCSA_Internal)
+      .Case(".protected", MCSA_Protected)
+      .Default(MCSA_Invalid);
+    assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
+    if (getLexer().isNot(AsmToken::EndOfStatement)) {
+      while (true) {
+        StringRef Name;
+        if (getParser().parseIdentifier(Name))
+          return TokError("expected identifier in directive");
+        MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
+        getStreamer().EmitSymbolAttribute(Sym, Attr);
+        if (getLexer().is(AsmToken::EndOfStatement))
+          break;
+        if (getLexer().isNot(AsmToken::Comma))
+          return TokError("unexpected token in directive");
+        Lex();
+      }
+    }
+    Lex();
+    return false;
+  }
 };
 
 } // end anonymous namespace
 
 namespace llvm {
 
 MCAsmParserExtension *createWasmAsmParser() {
   return new WasmAsmParser;
 }
 
 } // end namespace llvm

test/MC/WebAssembly/basic-assembly.s

.LBB0_2:
     local.get   5
     block       void
     block       i64
     block       f32
     block       f64
     br_table {0, 1, 2}   # 2 entries, default
     end_block            # first entry jumps here.
     i32.const   1
-    br 2
+    br          2
     end_block            # second entry jumps here.
     i32.const   2
-    br 1
+    br          1
     end_block            # default jumps here.
     i32.const   3
     end_block            # "switch" exit.
-    if          # void
+    if                   # void
     if          i32
     end_if
     else
     end_if
     f32x4.add
     # Test correct parsing of instructions with / and : in them:
     # TODO: enable once instruction has been added.
     #i32x4.trunc_sat_f32x4_s
     i32.trunc_f32_s
     try         except_ref
     i32.atomic.load 0
     atomic.notify 0
 .LBB0_3:
     catch
-    local.set 0
+    local.set   0
     block       i32
-    local.get 0
-    br_on_exn 0, __cpp_exception
+    local.get   0
+    br_on_exn   0, __cpp_exception
     rethrow
 .LBB0_4:
     end_block
     end_try
-    i32.const .L.str
+    i32.const   .L.str
     throw 0
 .LBB0_5:
     #i32.trunc_sat_f32_s
     global.get  __stack_pointer
     end_function
 
-    .section  .rodata..L.str,"",@
+    .section    .rodata..L.str,"",@
+    .hidden     .L.str
 .L.str:
-    .int8 'H'
-    .asciz  "ello, World!"
-    .size .L.str, 14
+    .int8       'H'
+    .asciz      "ello, World!"
+    .size       .L.str, 14
 
-    .globaltype __stack_pointer, i32
+    .ident      "clang version 9.0.0 (trunk 364502) (llvm/trunk 364571)"
+    .globaltype __stack_pointer, i32
 
 # CHECK:           .text
 # CHECK-LABEL: test0:
-# CHECK-NEXT:      .functype test0 (i32, i64) -> (i32)
+# CHECK-NEXT:      .functype   test0 (i32, i64) -> (i32)
 # CHECK-NEXT:      .eventtype  __cpp_exception i32
 # CHECK-NEXT:      .local      f32, f64
 # CHECK-NEXT:      local.get   2
 # CHECK-NEXT:      local.set   2
 # CHECK-NEXT:      i32.const   -1
 # CHECK-NEXT:      f64.const   0x1.999999999999ap1
 # CHECK-NEXT:      v128.const  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
 # CHECK-NEXT:      v128.const  0, 1, 2, 3, 4, 5, 6, 7
 # CHECK-NEXT:      local.get   0
 # CHECK-NEXT:      f64.store   1234:p2align=4
 # CHECK-NEXT:      f64.store   1234
 # CHECK-NEXT:      block       i32
 # CHECK-NEXT:      i32.const   1
 # CHECK-NEXT:      local.get   0
 # CHECK-NEXT:      i32.ge_s
-# CHECK-NEXT:      br_if 0            # 0: down to label0
+# CHECK-NEXT:      br_if       0       # 0: down to label0
 # CHECK-NEXT:  .LBB0_1:
-# CHECK-NEXT:      loop        i32         # label1:
+# CHECK-NEXT:      loop        i32     # label1:
 # CHECK-NEXT:      call        something1
 # CHECK-NEXT:      i64.const   1234
 # CHECK-NEXT:      i32.call    something2
 # CHECK-NEXT:      i32.const   0
 # CHECK-NEXT:      call_indirect 0
 # CHECK-NEXT:      i32.const   1
 # CHECK-NEXT:      i32.add
 # CHECK-NEXT:      local.tee   0
 # CHECK-NEXT:      local.get   0
 # CHECK-NEXT:      i32.lt_s
-# CHECK-NEXT:      br_if 0            # 0: up to label1
+# CHECK-NEXT:      br_if       0       # 0: up to label1
 # CHECK-NEXT:  .LBB0_2:
 # CHECK-NEXT:      end_loop
-# CHECK-NEXT:      end_block                       # label0:
+# CHECK-NEXT:      end_block           # label0:
 # CHECK-NEXT:      local.get   4
 # CHECK-NEXT:      local.get   5
 # CHECK-NEXT:      block
 # CHECK-NEXT:      block       i64
 # CHECK-NEXT:      block       f32
 # CHECK-NEXT:      block       f64
 # CHECK-NEXT:      br_table {0, 1, 2}  # 1: down to label4
 # CHECK-NEXT:                          # 2: down to label3
 # CHECK-NEXT:      end_block           # label5:
-# CHECK-NEXT:      i32.const 1
-# CHECK-NEXT:      br 2                # 2: down to label2
+# CHECK-NEXT:      i32.const   1
+# CHECK-NEXT:      br          2       # 2: down to label2
 # CHECK-NEXT:      end_block           # label4:
-# CHECK-NEXT:      i32.const 2
-# CHECK-NEXT:      br 1                # 1: down to label2
+# CHECK-NEXT:      i32.const   2
+# CHECK-NEXT:      br          1       # 1: down to label2
 # CHECK-NEXT:      end_block           # label3:
-# CHECK-NEXT:      i32.const 3
+# CHECK-NEXT:      i32.const   3
 # CHECK-NEXT:      end_block           # label2:
 # CHECK-NEXT:      if
 # CHECK-NEXT:      if          i32
 # CHECK-NEXT:      end_if
 # CHECK-NEXT:      else
 # CHECK-NEXT:      end_if
 # CHECK-NEXT:      f32x4.add
 # CHECK-NEXT:      i32.trunc_f32_s
 # CHECK-NEXT:      try         except_ref
 # CHECK-NEXT:      i32.atomic.load 0
 # CHECK-NEXT:      atomic.notify 0
 # CHECK-NEXT:  .LBB0_3:
 # CHECK-NEXT:      catch
-# CHECK-NEXT:      local.set 0
+# CHECK-NEXT:      local.set   0
 # CHECK-NEXT:      block       i32
-# CHECK-NEXT:      local.get 0
-# CHECK-NEXT:      br_on_exn 0, __cpp_exception
+# CHECK-NEXT:      local.get   0
+# CHECK-NEXT:      br_on_exn   0, __cpp_exception
 # CHECK-NEXT:      rethrow
 # CHECK-NEXT:  .LBB0_4:
 # CHECK-NEXT:      end_block
 # CHECK-NEXT:      end_try
-# CHECK-NEXT:      i32.const .L.str
-# CHECK-NEXT:      throw 0
+# CHECK-NEXT:      i32.const   .L.str
+# CHECK-NEXT:      throw       0
 # CHECK-NEXT:  .LBB0_5:
 # CHECK-NEXT:      global.get  __stack_pointer
 # CHECK-NEXT:      end_function
 
-# CHECK:      .section  .rodata..L.str,"",@
-# CHECK-NEXT:.L.str:
-# CHECK-NEXT: .int8 72
-# CHECK-NEXT: .asciz  "ello, World!"
+# CHECK:           .section    .rodata..L.str,"",@
+# CHECK-NEXT:      .hidden     .L.str
+# CHECK-NEXT:  .L.str:
+# CHECK-NEXT:      .int8       72
+# CHECK-NEXT:      .asciz      "ello, World!"
 
-# CHECK:           .globaltype  __stack_pointer, i32
+# CHECK:           .globaltype __stack_pointer, i32