[PATCH] D85567: [lld][WebAssembly] Handle weakly referenced symbols when lazy (archive) version is see first

[Sam Clegg via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGb34ec5969f1a: [lld][WebAssembly] Handle weakly referenced symbols when lazy (archive) version… (authored by sbc100).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85567/new/

https://reviews.llvm.org/D85567

Files:
  lld/test/wasm/archive-weak-undefined.ll
  lld/wasm/SymbolTable.cpp
  lld/wasm/Symbols.cpp
  lld/wasm/Symbols.h


Index: lld/wasm/Symbols.h
===================================================================
--- lld/wasm/Symbols.h
+++ lld/wasm/Symbols.h
@@ -411,6 +411,7 @@
 
   static bool classof(const Symbol *s) { return s->kind() == LazyKind; }
   void fetch();
+  void setWeak();
   MemoryBufferRef getMemberBuffer();
 
   // Lazy symbols can have a signature because they can replace an
Index: lld/wasm/Symbols.cpp
===================================================================
--- lld/wasm/Symbols.cpp
+++ lld/wasm/Symbols.cpp
@@ -339,6 +339,10 @@
 
 void LazySymbol::fetch() { cast<ArchiveFile>(file)->addMember(&archiveSymbol); }
 
+void LazySymbol::setWeak() {
+  flags |= (flags & ~WASM_SYMBOL_BINDING_MASK) | WASM_SYMBOL_BINDING_WEAK;
+}
+
 MemoryBufferRef LazySymbol::getMemberBuffer() {
   Archive::Child c =
       CHECK(archiveSymbol.getMember(),
Index: lld/wasm/SymbolTable.cpp
===================================================================
--- lld/wasm/SymbolTable.cpp
+++ lld/wasm/SymbolTable.cpp
@@ -458,11 +458,16 @@
                                      file, sig, isCalledDirectly);
   };
 
-  if (wasInserted)
+  if (wasInserted) {
     replaceSym();
-  else if (auto *lazy = dyn_cast<LazySymbol>(s))
-    lazy->fetch();
-  else {
+  } else if (auto *lazy = dyn_cast<LazySymbol>(s)) {
+    if ((flags & WASM_SYMBOL_BINDING_MASK) == WASM_SYMBOL_BINDING_WEAK) {
+      lazy->setWeak();
+      lazy->signature = sig;
+    } else {
+      lazy->fetch();
+    }
+  } else {
     auto existingFunction = dyn_cast<FunctionSymbol>(s);
     if (!existingFunction) {
       reportTypeError(s, file, WASM_SYMBOL_TYPE_FUNCTION);
@@ -499,12 +504,16 @@
   if (s->traced)
     printTraceSymbolUndefined(name, file);
 
-  if (wasInserted)
+  if (wasInserted) {
     replaceSymbol<UndefinedData>(s, name, flags, file);
-  else if (auto *lazy = dyn_cast<LazySymbol>(s))
-    lazy->fetch();
-  else if (s->isDefined())
+  } else if (auto *lazy = dyn_cast<LazySymbol>(s)) {
+    if ((flags & WASM_SYMBOL_BINDING_MASK) == WASM_SYMBOL_BINDING_WEAK)
+      lazy->setWeak();
+    else
+      lazy->fetch();
+  } else if (s->isDefined()) {
     checkDataType(s, file);
+  }
   return s;
 }
 
Index: lld/test/wasm/archive-weak-undefined.ll
===================================================================
--- lld/test/wasm/archive-weak-undefined.ll
+++ lld/test/wasm/archive-weak-undefined.ll
@@ -1,4 +1,4 @@
-; Test that weak undefined symbols do not fetch members from archive files.
+;; Test that weak undefined symbols do not fetch members from archive files.
 ; RUN: llc -filetype=obj %s -o %t.o
 ; RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/ret32.s -o %t.ret32.o
 ; RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/hello.s -o %t.hello.o
@@ -8,6 +8,10 @@
 ; RUN: wasm-ld %t.o %t.a -o %t.wasm
 ; RUN: obj2yaml %t.wasm | FileCheck %s
 
+;; Also test with the library symbols being read first
+; RUN: wasm-ld %t.a %t.o -o %t2.wasm
+; RUN: obj2yaml %t2.wasm | FileCheck %s
+
 ; RUN: wasm-ld -u hello_str %t.o %t.a -o %t2.wasm
 ; RUN: obj2yaml %t2.wasm | FileCheck %s -check-prefix=CHECK-DATA
 


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