[lld][WebAssembly] Add test for TLS BSS data. NFC.

[sbc100]

• update expectation

lld/test/wasm/tls.s

 .globl tls2_addr
 tls2_addr:
   .functype tls2_addr () -> (i32)
   global.get __tls_base
   i32.const tls2
   i32.add
   end_function
 
+.globl tls3_addr
+tls3_addr:
+  .functype tls3_addr () -> (i32)
+  global.get __tls_base
+  i32.const tls3
+  i32.add
+  end_function
+
 .globl tls_align
 tls_align:
   .functype tls_align () -> (i32)
   global.get __tls_align
   end_function
 
 .section  .bss.no_tls,"",@
 .globl  no_tls

 
 .section  .tdata.tls2,"",@
 .globl  tls2
 .p2align  2
 tls2:
   .int32  1
   .size tls2, 4
 
+.section  .tbss.tls3,"",@
+.globl  tls3
+.p2align  2
+tls3:
+  .int32  0
+  .size tls3, 4
+
 .section  .custom_section.target_features,"",@
   .int8 2
   .int8 43
   .int8 7
   .ascii  "atomics"
   .int8 43
   .int8 11
   .ascii  "bulk-memory"
 
 # RUN: wasm-ld -no-gc-sections --shared-memory --max-memory=131072 --no-entry -o %t.wasm %t.o
 # RUN: obj2yaml %t.wasm | FileCheck %s
 
 # RUN: wasm-ld -no-gc-sections --shared-memory --max-memory=131072 --no-merge-data-segments --no-entry -o %t.wasm %t.o
 # RUN: obj2yaml %t.wasm | FileCheck %s
 
 # CHECK:      - Type:            GLOBAL
 # CHECK-NEXT:   Globals:
 # CHECK-NEXT:     - Index:           0
 # CHECK-NEXT:       Type:            I32
 # CHECK-NEXT:       Mutable:         true
 # CHECK-NEXT:       InitExpr:
 # CHECK-NEXT:         Opcode:          I32_CONST
-# CHECK-NEXT:         Value:           66576
+# CHECK-NEXT:         Value:           66592
 
 # __tls_base
 # CHECK-NEXT:     - Index:           1
 # CHECK-NEXT:       Type:            I32
 # CHECK-NEXT:       Mutable:         true
 # CHECK-NEXT:       InitExpr:
 # CHECK-NEXT:         Opcode:          I32_CONST
 # CHECK-NEXT:         Value:           0
 
 # __tls_size
 # CHECK-NEXT:     - Index:           2
 # CHECK-NEXT:       Type:            I32
 # CHECK-NEXT:       Mutable:         false
 # CHECK-NEXT:       InitExpr:
 # CHECK-NEXT:         Opcode:          I32_CONST
-# CHECK-NEXT:         Value:           8
+# CHECK-NEXT:         Value:           12
 
 # __tls_align
 # CHECK-NEXT:     - Index:           3
 # CHECK-NEXT:       Type:            I32
 # CHECK-NEXT:       Mutable:         false
 # CHECK-NEXT:       InitExpr:
 # CHECK-NEXT:         Opcode:          I32_CONST
 # CHECK-NEXT:         Value:           4
 
 
 # CHECK:      - Type:            CODE
 # CHECK-NEXT:   Functions:
 # Skip __wasm_call_ctors and __wasm_init_memory
 # CHECK:          - Index:           2
 # CHECK-NEXT:       Locals:          []
-# CHECK-NEXT:       Body:            20002401200041004108FC0800000B
+# CHECK-NEXT:       Body:            2000240120004100410CFC0800000B
 
 # Expected body of __wasm_init_tls:
 #   local.get 0
 #   global.set  1
 #   local.get 0
 #   i32.const 0
-#   i32.const 8
+#   i32.const 12
 #   memory.init 1, 0
 #   end
 
 # CHECK-NEXT:     - Index:           3
 # CHECK-NEXT:       Locals:          []
 # CHECK-NEXT:       Body:            2381808080004180808080006A0B
 
 # Expected body of tls1_addr:
 #   global.get 1
 #   i32.const 0
 #   i32.add
 #   end
 
 # CHECK-NEXT:     - Index:           4
 # CHECK-NEXT:       Locals:          []
 # CHECK-NEXT:       Body:            2381808080004184808080006A0B
 
-# Expected body of tls1_addr:
+# Expected body of tls2_addr:
 #   global.get 1
 #   i32.const 4
 #   i32.add
 #   end
 
 # CHECK-NEXT:     - Index:           5
 # CHECK-NEXT:       Locals:          []
+# CHECK-NEXT:       Body:            2381808080004188808080006A0B
+
+# Expected body of tls3_addr:
+#   global.get 1
+#   i32.const 4
+#   i32.add
+#   end
+
+# CHECK-NEXT:     - Index:           6
+# CHECK-NEXT:       Locals:          []
 # CHECK-NEXT:       Body:            2383808080000B
 
-# Expected body of tls1_addr:
+# Expected body of tls_align:
 #   global.get 3
 #   end

llvm/lib/MC/MCParser/WasmAsmParser.cpp

if (expect(AsmToken::Comma, ","))
       return true;
 
     if (Lexer->isNot(AsmToken::String))
       return error("expected string in directive, instead got: ", Lexer->getTok());
 
     auto Kind = StringSwitch<Optional<SectionKind>>(Name)
                     .StartsWith(".data", SectionKind::getData())
                     .StartsWith(".tdata", SectionKind::getThreadData())
+                    .StartsWith(".tbss", SectionKind::getThreadBSS())
                     .StartsWith(".rodata", SectionKind::getReadOnly())
                     .StartsWith(".text", SectionKind::getText())
                     .StartsWith(".custom_section", SectionKind::getMetadata())
                     .StartsWith(".bss", SectionKind::getBSS())
                     // See use of .init_array in WasmObjectWriter and
                     // TargetLoweringObjectFileWasm
                     .StartsWith(".init_array", SectionKind::getData())
                     .StartsWith(".debug_", SectionKind::getMetadata())