[WebAssembly] Fix list of relocations with addends in lld

Summary:
The list of relocations with addend in lld was missing `R_WASM_MEMORY_ADDR_REL_SLEB`,
causing `wasm-ld` to generate corrupted output. This fixes that problem and while
we're at it pulls the list of such relocations into the Wasm.h header, to avoid
duplicating it in multiple places.

Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63696

llvm-svn: 364367

Author: Keno

lld/test/wasm/emit-relocs-fpic.s

@@ -0,0 +1,20 @@
+# RUN: llvm-mc -triple=wasm32-unknown-unknown -filetype=obj -o %t.o < %s
+# RUN: llc --relocation-model=pic -filetype=obj %p/Inputs/ret32.ll -o %t.ret32.o
+# RUN: wasm-ld -pie --export-all --no-gc-sections --no-entry --emit-relocs -o %t.wasm %t.o %t.ret32.o
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+load_hidden_data:
+    .functype   load_hidden_data () -> (i32)
+    i32.const   .L.hidden_data@MBREL
+    end_function
+
+.section .rodata.hidden_data,"",@
+.L.hidden_data:
+    .int8 100
+    .size .L.hidden_data, 1
+
+# We just want to make sure that processing this relocation doesn't
+# cause corrupt output. We get most of the way there, by just checking
+# that obj2yaml doesn't fail. Here we just make sure that the relocation
+# survived the trip.
+# CHECK: R_WASM_MEMORY_ADDR_REL_SLEB

lld/test/wasm/lit.local.cfg

@@ -1,4 +1,4 @@
 if 'wasm' not in config.available_features:
   config.unsupported = True
 
-config.suffixes = ['.test', '.yaml', '.ll']
+config.suffixes = ['.test', '.yaml', '.ll', '.s']

lld/wasm/InputChunks.cpp

@@ -154,15 +154,8 @@ void InputChunk::writeRelocations(raw_ostream &OS) const {
     writeUleb128(OS, Rel.Offset + Off, "reloc offset");
     writeUleb128(OS, File->calcNewIndex(Rel), "reloc index");
 
-    switch (Rel.Type) {
-    case R_WASM_MEMORY_ADDR_LEB:
-    case R_WASM_MEMORY_ADDR_SLEB:
-    case R_WASM_MEMORY_ADDR_I32:
-    case R_WASM_FUNCTION_OFFSET_I32:
-    case R_WASM_SECTION_OFFSET_I32:
+    if (relocTypeHasAddend(Rel.Type))
       writeSleb128(OS, File->calcNewAddend(Rel), "reloc addend");
-      break;
-    }
   }
 }
 

llvm/include/llvm/BinaryFormat/Wasm.h

@@ -364,6 +364,7 @@ inline bool operator!=(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
 
 std::string toString(WasmSymbolType type);
 std::string relocTypetoString(uint32_t type);
+bool relocTypeHasAddend(uint32_t type);
 
 } // end namespace wasm
 } // end namespace llvm

llvm/lib/BinaryFormat/Wasm.cpp

@@ -35,3 +35,17 @@ std::string llvm::wasm::relocTypetoString(uint32_t Type) {
     llvm_unreachable("unknown reloc type");
   }
 }
+
+bool llvm::wasm::relocTypeHasAddend(uint32_t Type) {
+  switch (Type) {
+  case R_WASM_MEMORY_ADDR_LEB:
+  case R_WASM_MEMORY_ADDR_SLEB:
+  case R_WASM_MEMORY_ADDR_REL_SLEB:
+  case R_WASM_MEMORY_ADDR_I32:
+  case R_WASM_FUNCTION_OFFSET_I32:
+  case R_WASM_SECTION_OFFSET_I32:
+    return true;
+  default:
+    return false;
+  }
+}

llvm/lib/MC/WasmObjectWriter.cpp

@@ -147,19 +147,7 @@ struct WasmRelocationEntry {
       : Offset(Offset), Symbol(Symbol), Addend(Addend), Type(Type),
         FixupSection(FixupSection) {}
 
-  bool hasAddend() const {
-    switch (Type) {
-    case wasm::R_WASM_MEMORY_ADDR_LEB:
-    case wasm::R_WASM_MEMORY_ADDR_SLEB:
-    case wasm::R_WASM_MEMORY_ADDR_REL_SLEB:
-    case wasm::R_WASM_MEMORY_ADDR_I32:
-    case wasm::R_WASM_FUNCTION_OFFSET_I32:
-    case wasm::R_WASM_SECTION_OFFSET_I32:
-      return true;
-    default:
-      return false;
-    }
-  }
+  bool hasAddend() const { return wasm::relocTypeHasAddend(Type); }
 
   void print(raw_ostream &Out) const {
     Out << wasm::relocTypetoString(Type) << " Off=" << Offset