[PATCH] D63342: lld/elf: Extract undefined symbol diagnostic emission into its own function

[Nico Weber via Phabricator via llvm-commits]

thakis created this revision.
thakis added a reviewer: ruiu.
Herald added subscribers: MaskRay, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.
thakis added a child revision: D63343: lld/elf: Serialize undefined symbol diagnostics, emit them in one go later.

Part of PR42260.


https://reviews.llvm.org/D63342

Files:
  lld/ELF/Relocations.cpp


Index: lld/ELF/Relocations.cpp
===================================================================
--- lld/ELF/Relocations.cpp
+++ lld/ELF/Relocations.cpp
@@ -705,27 +705,18 @@
   return Msg;
 }
 
-// Report an undefined symbol if necessary.
-// Returns true if this function printed out an error message.
-template <class ELFT>
-static bool maybeReportUndefined(Symbol &Sym, InputSectionBase &Sec,
-                                 uint64_t Offset) {
-  if (!Sym.isUndefined() || Sym.isWeak())
-    return false;
-
-  bool CanBeExternal = !Sym.isLocal() && Sym.computeBinding() != STB_LOCAL &&
-                       Sym.Visibility == STV_DEFAULT;
-  if (Config->UnresolvedSymbols == UnresolvedPolicy::Ignore && CanBeExternal)
-    return false;
+struct UndefinedDiag {
+  Symbol *Sym;
+  InputSectionBase *Sec;
+  uint64_t Offset;
+  bool IsWarning;
+};
 
-  // clang (as of 2019-06-12) / gcc (as of 8.2.1) PPC64 may emit a .rela.toc
-  // which references a switch table in a discarded .rodata/.text section. The
-  // .toc and the .rela.toc are incorrectly not placed in the comdat. The ELF
-  // spec says references from outside the group to a STB_LOCAL symbol are not
-  // allowed. Work around the bug.
-  if (Config->EMachine == EM_PPC64 &&
-      cast<Undefined>(Sym).DiscardedSecIdx != 0 && Sec.Name == ".toc")
-    return false;
+template <class ELFT>
+static void reportUndefinedSymbol(const UndefinedDiag &Undef) {
+  Symbol &Sym = *Undef.Sym;
+  InputSectionBase &Sec = *Undef.Sec;
+  uint64_t Offset = Undef.Offset;
 
   auto Visibility = [&]() -> std::string {
     switch (Sym.Visibility) {
@@ -754,14 +745,41 @@
     Msg += "\nthe vtable symbol may be undefined because the class is missing "
            "its key function (see https://lld.llvm.org/missingkeyfunction)";
 
-  if ((Config->UnresolvedSymbols == UnresolvedPolicy::Warn && CanBeExternal) ||
-      Config->NoinhibitExec) {
+  if (Undef.IsWarning)
     warn(Msg);
+  else
+    error(Msg);
+}
+
+// Report an undefined symbol if necessary.
+// Returns true if this function printed out an error message.
+template <class ELFT>
+static bool maybeReportUndefined(Symbol &Sym, InputSectionBase &Sec,
+                                 uint64_t Offset) {
+  if (!Sym.isUndefined() || Sym.isWeak())
     return false;
-  }
 
-  error(Msg);
-  return true;
+  bool CanBeExternal = !Sym.isLocal() && Sym.computeBinding() != STB_LOCAL &&
+                       Sym.Visibility == STV_DEFAULT;
+  if (Config->UnresolvedSymbols == UnresolvedPolicy::Ignore && CanBeExternal)
+    return false;
+
+  // clang (as of 2019-06-12) / gcc (as of 8.2.1) PPC64 may emit a .rela.toc
+  // which references a switch table in a discarded .rodata/.text section. The
+  // .toc and the .rela.toc are incorrectly not placed in the comdat. The ELF
+  // spec says references from outside the group to a STB_LOCAL symbol are not
+  // allowed. Work around the bug.
+  if (Config->EMachine == EM_PPC64 &&
+      cast<Undefined>(Sym).DiscardedSecIdx != 0 && Sec.Name == ".toc")
+    return false;
+
+
+  UndefinedDiag Undef = { &Sym, &Sec, Offset, /*IsWarning=*/false };
+  if ((Config->UnresolvedSymbols == UnresolvedPolicy::Warn && CanBeExternal) ||
+      Config->NoinhibitExec)
+    Undef.IsWarning = true;
+  reportUndefinedSymbol<ELFT>(Undef);
+  return !Undef.IsWarning;
 }
 
 // MIPS N32 ABI treats series of successive relocations with the same offset


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