From: Vitaly Buka <vitalybuka@google.com>
Date: Tue, 15 Nov 2016 07:32:51 +0000 (+0000)
Subject: Avoid creating reference from nullptr.
X-Git-Tag: llvmorg-4.0.0-rc1~4567
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=029d730bade89fa97b0c4f910975f91f16682283;p=platform%2Fupstream%2Fllvm.git

Avoid creating reference from nullptr.

Summary:
getFile() can return nullptr. This usually happens when Rels is empty so
the reference is never used. Still UBSAN complains.

Reviewers: rafael

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D26662

llvm-svn: 286937
---

diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index 55665dea..302dc5a 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -615,7 +615,7 @@ static void scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
     Out<ELFT>::RelaDyn->addReloc(Reloc);
   };
 
-  const elf::ObjectFile<ELFT> &File = *C.getFile();
+  const elf::ObjectFile<ELFT> *File = C.getFile();
   ArrayRef<uint8_t> SectionData = C.Data;
   const uint8_t *Buf = SectionData.begin();
 
@@ -628,7 +628,7 @@ static void scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
 
   for (auto I = Rels.begin(), E = Rels.end(); I != E; ++I) {
     const RelTy &RI = *I;
-    SymbolBody &Body = File.getRelocTargetSym(RI);
+    SymbolBody &Body = File->getRelocTargetSym(RI);
     uint32_t Type = RI.getType(Config->Mips64EL);
 
     if (Config->MipsN32Abi) {
@@ -645,7 +645,7 @@ static void scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
 
     RelExpr Expr = Target->getRelExpr(Type, Body);
     bool Preemptible = isPreemptible(Body, Type);
-    Expr = adjustExpr(File, Body, IsWrite, Expr, Type, Buf + RI.r_offset);
+    Expr = adjustExpr(*File, Body, IsWrite, Expr, Type, Buf + RI.r_offset);
     if (HasError)
       continue;
 
@@ -673,7 +673,7 @@ static void scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
         Expr == R_GOTREL || Expr == R_GOTREL_FROM_END || Expr == R_PPC_TOC)
       In<ELFT>::Got->HasGotOffRel = true;
 
-    uintX_t Addend = computeAddend(File, Buf, E, RI, Expr, Body);
+    uintX_t Addend = computeAddend(*File, Buf, E, RI, Expr, Body);
 
     if (unsigned Processed =
             handleTlsRelocation<ELFT>(Type, Body, C, Offset, Addend, Expr)) {
@@ -796,14 +796,14 @@ template <class ELFT> void scanRelocations(InputSectionBase<ELFT> &S) {
 
 template <class ELFT, class RelTy>
 static void createThunks(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
-  const elf::ObjectFile<ELFT> &File = *C.getFile();
+  const elf::ObjectFile<ELFT> *File = C.getFile();
   for (const RelTy &Rel : Rels) {
-    SymbolBody &Body = File.getRelocTargetSym(Rel);
+    SymbolBody &Body = File->getRelocTargetSym(Rel);
     uint32_t Type = Rel.getType(Config->Mips64EL);
     RelExpr Expr = Target->getRelExpr(Type, Body);
     if (!isPreemptible(Body, Type) && needsPlt(Expr))
       Expr = fromPlt(Expr);
-    Expr = Target->getThunkExpr(Expr, Type, File, Body);
+    Expr = Target->getThunkExpr(Expr, Type, *File, Body);
     // Some targets might require creation of thunks for relocations.
     // Now we support only MIPS which requires LA25 thunk to call PIC
     // code from non-PIC one, and ARM which requires interworking.