[PATCH] D59860: [WebAssembly] Improve invalid relocation error message

[Sam Clegg via Phabricator via llvm-commits]

sbc100 created this revision.
Herald added subscribers: llvm-commits, jdoerfert, sunfish, aheejin, jgravelle-google, dschuff.
Herald added a project: LLVM.
sbc100 added a reviewer: ruiu.

This message now matches the equivalent message in the ELF linker.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D59860

Files:
  lld/test/wasm/undefined-data.ll
  lld/wasm/InputChunks.cpp
  lld/wasm/InputChunks.h
  lld/wasm/Writer.cpp


Index: lld/wasm/Writer.cpp
===================================================================
--- lld/wasm/Writer.cpp
+++ lld/wasm/Writer.cpp
@@ -1124,6 +1124,7 @@
   if (!Chunk->Live)
     return;
   ObjFile *File = Chunk->File;
+
   ArrayRef<WasmSignature> Types = File->getWasmObj()->types();
   for (const WasmRelocation &Reloc : Chunk->getRelocations()) {
     switch (Reloc.Type) {
@@ -1141,18 +1142,6 @@
       File->TypeMap[Reloc.Index] = registerType(Types[Reloc.Index]);
       File->TypeIsUsed[Reloc.Index] = true;
       break;
-    case R_WASM_MEMORY_ADDR_SLEB:
-    case R_WASM_MEMORY_ADDR_I32:
-    case R_WASM_MEMORY_ADDR_LEB: {
-      DataSymbol *DataSym = File->getDataSymbol(Reloc.Index);
-      if (!Config->Relocatable && !isa<DefinedData>(DataSym) &&
-          !DataSym->isWeak())
-        error(File->getName() +
-              ": relocation of type R_WASM_MEMORY_ADDR_* "
-              "against undefined data symbol: " +
-              DataSym->getName());
-      break;
-    }
     case R_WASM_GLOBAL_INDEX_LEB: {
       auto* Sym = File->getSymbols()[Reloc.Index];
       if (!isa<GlobalSymbol>(Sym) && !Sym->isInGOT()) {
@@ -1161,7 +1150,24 @@
       }
     }
     }
+
+    if (!Config->Relocatable) {
+      switch (Reloc.Type) {
+      // These relocations types appear the code section.
+      // They should never appear in code compiled with -fPIC.
+      case R_WASM_TABLE_INDEX_SLEB:
+      case R_WASM_MEMORY_ADDR_SLEB:
+      case R_WASM_MEMORY_ADDR_LEB: {
+        auto *Sym = File->getSymbols()[Reloc.Index];
+        if (!Config->Relocatable && Sym->isUndefined() && !Sym->isWeak())
+          error(File->getName() + ": relocation " + reloctTypeToString(Reloc.Type) +
+                " cannot be used againt symbol " + Sym->getName() +
+              "; recompile with -fPIC");
+      }
+      }
+    }
   }
+
 }
 
 void Writer::assignIndexes() {
Index: lld/wasm/InputChunks.h
===================================================================
--- lld/wasm/InputChunks.h
+++ lld/wasm/InputChunks.h
@@ -218,6 +218,8 @@
 } // namespace wasm
 
 std::string toString(const wasm::InputChunk *);
+StringRef reloctTypeToString(uint8_t RelocType);
+
 } // namespace lld
 
 #endif // LLD_WASM_INPUT_CHUNKS_H
Index: lld/wasm/InputChunks.cpp
===================================================================
--- lld/wasm/InputChunks.cpp
+++ lld/wasm/InputChunks.cpp
@@ -22,7 +22,7 @@
 using namespace lld;
 using namespace lld::wasm;
 
-static StringRef reloctTypeToString(uint8_t RelocType) {
+StringRef lld::reloctTypeToString(uint8_t RelocType) {
   switch (RelocType) {
 #define WASM_RELOC(NAME, REL)                                                  \
   case REL:                                                                    \
Index: lld/test/wasm/undefined-data.ll
===================================================================
--- lld/test/wasm/undefined-data.ll
+++ lld/test/wasm/undefined-data.ll
@@ -13,4 +13,4 @@
 }
 
 ; UNDEF: undefined symbol: data_external
-; BADRELOC: undefined-data.ll.tmp.o: relocation of type R_WASM_MEMORY_ADDR_* against undefined data symbol: data_external
+; BADRELOC: relocation R_WASM_MEMORY_ADDR_LEB cannot be used againt symbol data_external; recompile with -fPIC


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