From 3d9f1c032addbff1c38e56c83b01c3b43c36af6e Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 13 Sep 2017 20:43:04 +0000
Subject: [PATCH] Add a helper for checking for weak undef. NFC.

llvm-svn: 313188
---
 lld/ELF/Arch/ARM.cpp     |  3 +--
 lld/ELF/InputSection.cpp |  4 ++--
 lld/ELF/Relocations.cpp  |  6 +++---
 lld/ELF/Symbols.cpp      | 12 ++++++++++--
 lld/ELF/Symbols.h        |  5 +++++
 5 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/lld/ELF/Arch/ARM.cpp b/lld/ELF/Arch/ARM.cpp
index 37f4eae91cfa..8b4044d51998 100644
--- a/lld/ELF/Arch/ARM.cpp
+++ b/lld/ELF/Arch/ARM.cpp
@@ -194,8 +194,7 @@ bool ARM::needsThunk(RelExpr Expr, uint32_t RelocType, const InputFile *File,
   // If S is an undefined weak symbol in an executable we don't need a Thunk.
   // In a DSO calls to undefined symbols, including weak ones get PLT entries
   // which may need a thunk.
-  if (S.isUndefined() && !S.isLocal() && S.symbol()->isWeak() &&
-      !Config->Shared)
+  if (S.isUndefWeak() && !Config->Shared)
     return false;
   // A state change from ARM to Thumb and vice versa must go through an
   // interworking thunk if the relocation type is not R_ARM_CALL or
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 9e50d970729e..7183df80c67a 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -560,7 +560,7 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P,
   case R_PAGE_PC:
   case R_PLT_PAGE_PC: {
     uint64_t Dest;
-    if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak())
+    if (Body.isUndefWeak())
       Dest = getAArch64Page(A);
     else
       Dest = getAArch64Page(Body.getVA(A));
@@ -568,7 +568,7 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P,
   }
   case R_PC: {
     uint64_t Dest;
-    if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak()) {
+    if (Body.isUndefWeak()) {
       // On ARM and AArch64 a branch to an undefined weak resolves to the
       // next instruction, otherwise the place.
       if (Config->EMachine == EM_ARM)
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index a8d4a5403848..20b506d20d83 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -319,8 +319,8 @@ static uint32_t getMipsPairType(uint32_t Type, const SymbolBody &Sym) {
 // True if non-preemptable symbol always has the same value regardless of where
 // the DSO is loaded.
 static bool isAbsolute(const SymbolBody &Body) {
-  if (Body.isUndefined())
-    return !Body.isLocal() && Body.symbol()->isWeak();
+  if (Body.isUndefWeak())
+    return true;
   if (const auto *DR = dyn_cast<DefinedRegular>(&Body))
     return DR->Section == nullptr; // Absolute symbol.
   return false;
@@ -402,7 +402,7 @@ static bool isStaticLinkTimeConstant(RelExpr E, uint32_t Type,
   // between start of a function and '_gp' value and defined as absolute just
   // to simplify the code.
   assert(AbsVal && RelE);
-  if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak())
+  if (Body.isUndefWeak())
     return true;
 
   error("relocation " + toString(Type) + " cannot refer to absolute symbol: " +
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index 906d32589cd2..e11d39b4c2ee 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -132,6 +132,12 @@ SymbolBody::SymbolBody(Kind K, StringRefZ Name, bool IsLocal, uint8_t StOther,
       IsInIgot(false), IsPreemptible(false), Type(Type), StOther(StOther),
       Name(Name) {}
 
+bool SymbolBody::isUndefWeak() const {
+  if (isLocal())
+    return false;
+  return symbol()->isWeak() && (isUndefined() || isLazy());
+}
+
 InputFile *SymbolBody::getFile() const {
   if (isLocal()) {
     const SectionBase *Sec = cast<DefinedRegular>(this)->Section;
@@ -340,8 +346,10 @@ uint8_t Symbol::computeBinding() const {
 bool Symbol::includeInDynsym() const {
   if (computeBinding() == STB_LOCAL)
     return false;
-  if (body()->isUndefined() || body()->isLazy())
-    return Config->Shared || !body()->symbol()->isWeak();
+  if (body()->isUndefWeak())
+    return Config->Shared;
+  if (!body()->isInCurrentDSO())
+    return true;
   return ExportDynamic || body()->isShared();
 }
 
diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
index 11364807874b..fe9457fa56cb 100644
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -70,6 +70,11 @@ public:
     return !isUndefined() && !isShared() && !isLazy();
   }
   bool isLocal() const { return IsLocal; }
+
+  // True is this is an undefined weak symbol. This only works once
+  // all input files have been added.
+  bool isUndefWeak() const;
+
   InputFile *getFile() const;
   bool isPreemptible() const { return IsPreemptible; }
   StringRef getName() const { return Name; }