[PATCH] D40725: Wasm entrypoint changes #3 (add --no-entry argument to LLD) APPLY AFTER D40559

[Nicholas Wilson via Phabricator via llvm-commits]

ncw updated this revision to Diff 125701.
ncw marked an inline comment as done.
ncw added a comment.

Updated with changes as requested (and rebased)


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D40725

Files:
  test/wasm/data-layout.ll
  wasm/Driver.cpp
  wasm/Options.td
  wasm/Writer.cpp


Index: wasm/Writer.cpp
===================================================================
--- wasm/Writer.cpp
+++ wasm/Writer.cpp
@@ -265,7 +265,7 @@
   bool ExportMemory = !Config->Relocatable && !Config->ImportMemory;
   bool ExportOther = true; // ??? TODO Config->Relocatable;
   bool ExportHidden = Config->Relocatable;
-  Symbol *EntrySym = Symtab->find(Config->Entry);
+  Symbol *EntrySym = !Config->Entry.empty() ? Symtab->find(Config->Entry) : nullptr;
   bool ExportEntry = !Config->Relocatable && EntrySym && EntrySym->isDefined();
 
   uint32_t NumExports = 0;
Index: wasm/Options.td
===================================================================
--- wasm/Options.td
+++ wasm/Options.td
@@ -66,6 +66,9 @@
 def entry: S<"entry">, MetaVarName<"<entry>">,
   HelpText<"Name of entry point symbol">;
 
+def no_entry: F<"no-entry">,
+  HelpText<"Do not output any entry point">;
+
 def error_limit: J<"error-limit=">,
   HelpText<"Maximum number of errors to emit before stopping (0 = no limit)">;
 
Index: wasm/Driver.cpp
===================================================================
--- wasm/Driver.cpp
+++ wasm/Driver.cpp
@@ -215,6 +215,18 @@
     error("no input files");
 }
 
+static StringRef getEntry(opt::InputArgList &Args, StringRef def) {
+  auto *Arg = Args.getLastArg(OPT_entry, OPT_no_entry);
+  if (!Arg)
+    return def;
+  if (Arg->getOption().getID() == OPT_no_entry)
+    return StringRef();
+  StringRef Entry(Arg->getValue());
+  if (Entry.empty())
+    error("empty string invalid for entry point");
+  return Entry;
+}
+
 void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
   WasmOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
@@ -244,8 +256,8 @@
       Args.hasFlag(OPT_check_signatures, OPT_no_check_signatures, false);
   Config->EmitRelocs = Args.hasArg(OPT_emit_relocs);
   Config->Relocatable = Args.hasArg(OPT_relocatable);
-  Config->Entry = Args.getLastArgValue(OPT_entry,
-                                       Config->Relocatable ? "" : "_start");
+  Config->Entry = getEntry(Args, Config->Relocatable ? StringRef()
+                                                     : StringRef("_start"));
   Config->ImportMemory = Args.hasArg(OPT_import_memory);
   Config->OutputFile = Args.getLastArgValue(OPT_o);
   Config->SearchPaths = args::getStrings(Args, OPT_L);
@@ -285,8 +297,11 @@
     }
 
     // Handle the `--undefined <sym>` options.
-    for (StringRef S : args::getStrings(Args, OPT_undefined))
+    for (StringRef S : args::getStrings(Args, OPT_undefined)) {
+      if (S.empty())
+        error("empty string invalid for undefined symbol");
       addSyntheticUndefinedFunction(S, nullptr);
+    }
 
     Config->StackPointerSymbol = addSyntheticGlobal("__stack_pointer", 0);
   }
@@ -309,8 +324,8 @@
 
   if (!Config->Entry.empty()) {
     Symbol *Sym = Symtab->find(Config->Entry);
-    if (!Sym->isFunction())
-      fatal("entry point is not a function: " + Sym->getName());
+    if (!Sym->isDefined())
+      error("entry point not found: " + Config->Entry);
   }
   for (StringRef S : args::getStrings(Args, OPT_undefined)) {
     Symbol *Sym = Symtab->find(S);
Index: test/wasm/data-layout.ll
===================================================================
--- test/wasm/data-layout.ll
+++ test/wasm/data-layout.ll
@@ -1,6 +1,6 @@
 ; RUN: llc -filetype=obj %p/Inputs/hello.ll -o %t.hello.o
 ; RUN: llc -filetype=obj %s -o %t.o
-; RUN: lld -flavor wasm --emit-relocs --allow-undefined --entry '' -o %t.wasm %t.o %t.hello.o
+; RUN: lld -flavor wasm --emit-relocs --allow-undefined --no-entry -o %t.wasm %t.o %t.hello.o
 ; RUN: obj2yaml %t.wasm | FileCheck %s
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"


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