[WebAssembly] Include function in wasm table when used in R_WASM_TABLE_INDEX_REL_SLEB

[sbc100]

Summary

This should have been part of rL357710 but was overlooked because
in our test code the function in question was also used in other
relocations that caused it to be added to the table anyway.

[ruiu]

LGTM

lld/test/wasm/shared.ll

entry:
   ret i32* @data_external
 }
 
 define default i8* @get_func_address() {
 entry:
   ret i8* bitcast (void ()* @func_external to i8*)
 }
 
+define default i8* @get_local_func_address() {
+entry:
+  ; Verify that a function which is otherwise not address taken *is* added to
+  ; the wasm table with referenced via R_WASM_TABLE_INDEX_REL_SLEB
+  ret i8* bitcast (i8* ()* @get_func_address to i8*)
+}
+
 declare void @func_external()
 
 ; check for dylink section at start
 
 ; CHECK:      Sections:
 ; CHECK-NEXT:   - Type:            CUSTOM
 ; CHECK-NEXT:     Name:            dylink
 ; CHECK-NEXT:     MemorySize:      20
 ; CHECK-NEXT:     MemoryAlignment: 2
-; CHECK-NEXT:     TableSize:       2
+; CHECK-NEXT:     TableSize:       3
 ; CHECK-NEXT:     TableAlignment:  0
 ; CHECK-NEXT:     Needed:          []
 ; CHECK-NEXT:   - Type:            TYPE
 
 ; check for import of __table_base and __memory_base globals
 
 ; CHECK:        - Type:            IMPORT
 ; CHECK-NEXT:     Imports:
 ; CHECK-NEXT:       - Module:          env
 ; CHECK-NEXT:         Field:           memory
 ; CHECK-NEXT:         Kind:            MEMORY
 ; CHECK-NEXT:         Memory:
 ; CHECK-NEXT:           Initial:       0x0000000
 ; CHECK-NEXT:       - Module:          env
 ; CHECK-NEXT:         Field:           __indirect_function_table
 ; CHECK-NEXT:         Kind:            TABLE
 ; CHECK-NEXT:         Table:
 ; CHECK-NEXT:           ElemType:        FUNCREF
 ; CHECK-NEXT:           Limits:
-; CHECK-NEXT:             Initial:         0x00000002
+; CHECK-NEXT:             Initial:         0x00000003
 ; CHECK-NEXT:       - Module:          env
 ; CHECK-NEXT:         Field:           __stack_pointer
 ; CHECK-NEXT:         Kind:            GLOBAL
 ; CHECK-NEXT:         GlobalType:      I32
 ; CHECK-NEXT:         GlobalMutable:   true
 ; CHECK-NEXT:       - Module:          env
 ; CHECK-NEXT:         Field:           __memory_base
 ; CHECK-NEXT:         Kind:            GLOBAL

 
 ; check for elem segment initialized with __table_base global as offset
 
 ; CHECK:        - Type:            ELEM
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - Offset:
 ; CHECK-NEXT:           Opcode:          GLOBAL_GET
 ; CHECK-NEXT:           Index:           2
-; CHECK-NEXT:         Functions:       [ 3, 0 ]
+; CHECK-NEXT:         Functions:       [ 5, 3, 0 ]
 
 ; check the generated code in __wasm_call_ctors and __wasm_apply_relocs functions
 ; TODO(sbc): Disassemble and verify instructions.
 
 ; CHECK:        - Type:            CODE
 ; CHECK-NEXT:     Functions:
 ; CHECK-NEXT:       - Index:           1
 ; CHECK-NEXT:         Locals:          []
 ; CHECK-NEXT:         Body:            10020B
 ; CHECK-NEXT:       - Index:           2
 ; CHECK-NEXT:         Locals:          []
-; CHECK-NEXT:         Body:            230141046A230241006A360200230141086A230241016A3602002301410C6A230141006A360200230141106A23033602000B
+; CHECK-NEXT:         Body:            230141046A230241016A360200230141086A230241026A3602002301410C6A230141006A360200230141106A23033602000B
 
 ; check the data segment initialized with __memory_base global as offset
 
 ; CHECK:        - Type:            DATA
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - SectionOffset:   6
 ; CHECK-NEXT:         InitFlags:       0
 ; CHECK-NEXT:         Offset:
 ; CHECK-NEXT:           Opcode:          GLOBAL_GET
 ; CHECK-NEXT:           Index:           1
-; CHECK-NEXT:         Content:         '0200000000000000010000000000000000000000'
+; CHECK-NEXT:         Content:         '0200000001000000020000000000000000000000'

lld/wasm/Writer.cpp

 void Writer::processRelocations(InputChunk *Chunk) {
   if (!Chunk->Live)
     return;
   ObjFile *File = Chunk->File;
   ArrayRef<WasmSignature> Types = File->getWasmObj()->types();
   for (const WasmRelocation &Reloc : Chunk->getRelocations()) {
     switch (Reloc.Type) {
     case R_WASM_TABLE_INDEX_I32:
-    case R_WASM_TABLE_INDEX_SLEB: {
+    case R_WASM_TABLE_INDEX_SLEB:
+    case R_WASM_TABLE_INDEX_REL_SLEB: {
       FunctionSymbol *Sym = File->getFunctionSymbol(Reloc.Index);
       if (Sym->hasTableIndex() || !Sym->hasFunctionIndex())
         continue;
       Sym->setTableIndex(TableBase + IndirectFunctions.size());
       IndirectFunctions.emplace_back(Sym);
       break;
     }
     case R_WASM_TYPE_INDEX_LEB: