1 files changed, 41 insertions, 22 deletions

diff --git a/ELF/Writer.cpp b/ELF/Writer.cpp
index 154de8cf6d18..bddc42e1acf9 100644
--- a/ELF/Writer.cpp
+++ b/ELF/Writer.cpp
@@ -250,6 +250,8 @@ template <class ELFT> void Writer<ELFT>::createSyntheticSections() {
   // Create singleton output sections.
   Out<ELFT>::Bss =
       make<OutputSection<ELFT>>(".bss", SHT_NOBITS, SHF_ALLOC | SHF_WRITE);
+  Out<ELFT>::BssRelRo = make<OutputSection<ELFT>>(".bss.rel.ro", SHT_NOBITS,
+                                                  SHF_ALLOC | SHF_WRITE);
   In<ELFT>::DynStrTab = make<StringTableSection<ELFT>>(".dynstr", true);
   In<ELFT>::Dynamic = make<DynamicSection<ELFT>>();
   Out<ELFT>::EhFrame = make<EhOutputSection<ELFT>>();
@@ -498,6 +500,8 @@ template <class ELFT> bool elf::isRelroSection(const OutputSectionBase *Sec) {
     return true;
   if (In<ELFT>::MipsGot && Sec == In<ELFT>::MipsGot->OutSec)
     return true;
+  if (Sec == Out<ELFT>::BssRelRo)
+    return true;
   StringRef S = Sec->getName();
   return S == ".data.rel.ro" || S == ".ctors" || S == ".dtors" || S == ".jcr" ||
          S == ".eh_frame" || S == ".openbsd.randomdata";
@@ -557,30 +561,38 @@ static bool compareSectionsNonScript(const OutputSectionBase *A,
 
   // If we got here we know that both A and B are in the same PT_LOAD.
 
-  // The TLS initialization block needs to be a single contiguous block in a R/W
-  // PT_LOAD, so stick TLS sections directly before R/W sections. The TLS NOBITS
-  // sections are placed here as they don't take up virtual address space in the
-  // PT_LOAD.
   bool AIsTls = A->Flags & SHF_TLS;
   bool BIsTls = B->Flags & SHF_TLS;
-  if (AIsTls != BIsTls)
-    return AIsTls;
-
-  // The next requirement we have is to put nobits sections last. The
-  // reason is that the only thing the dynamic linker will see about
-  // them is a p_memsz that is larger than p_filesz. Seeing that it
-  // zeros the end of the PT_LOAD, so that has to correspond to the
-  // nobits sections.
   bool AIsNoBits = A->Type == SHT_NOBITS;
   bool BIsNoBits = B->Type == SHT_NOBITS;
-  if (AIsNoBits != BIsNoBits)
-    return BIsNoBits;
 
-  // We place RelRo section before plain r/w ones.
+  // The first requirement we have is to put (non-TLS) nobits sections last. The
+  // reason is that the only thing the dynamic linker will see about them is a
+  // p_memsz that is larger than p_filesz. Seeing that it zeros the end of the
+  // PT_LOAD, so that has to correspond to the nobits sections.
+  bool AIsNonTlsNoBits = AIsNoBits && !AIsTls;
+  bool BIsNonTlsNoBits = BIsNoBits && !BIsTls;
+  if (AIsNonTlsNoBits != BIsNonTlsNoBits)
+    return BIsNonTlsNoBits;
+
+  // We place nobits RelRo sections before plain r/w ones, and non-nobits RelRo
+  // sections after r/w ones, so that the RelRo sections are contiguous.
   bool AIsRelRo = isRelroSection<ELFT>(A);
   bool BIsRelRo = isRelroSection<ELFT>(B);
   if (AIsRelRo != BIsRelRo)
-    return AIsRelRo;
+    return AIsNonTlsNoBits ? AIsRelRo : BIsRelRo;
+
+  // The TLS initialization block needs to be a single contiguous block in a R/W
+  // PT_LOAD, so stick TLS sections directly before the other RelRo R/W
+  // sections. The TLS NOBITS sections are placed here as they don't take up
+  // virtual address space in the PT_LOAD.
+  if (AIsTls != BIsTls)
+    return AIsTls;
+
+  // Within the TLS initialization block, the non-nobits sections need to appear
+  // first.
+  if (AIsNoBits != BIsNoBits)
+    return BIsNoBits;
 
   // Some architectures have additional ordering restrictions for sections
   // within the same PT_LOAD.
@@ -1071,6 +1083,8 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
 template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
   if (Out<ELFT>::Bss->Size > 0)
     OutputSections.push_back(Out<ELFT>::Bss);
+  if (Out<ELFT>::BssRelRo->Size > 0)
+    OutputSections.push_back(Out<ELFT>::BssRelRo);
 
   auto OS = dyn_cast_or_null<OutputSection<ELFT>>(findSection(".ARM.exidx"));
   if (OS && !OS->Sections.empty() && !Config->Relocatable)
@@ -1272,8 +1286,9 @@ void Writer<ELFT>::addPtArmExid(std::vector<PhdrEntry> &Phdrs) {
   Phdrs.push_back(ARMExidx);
 }
 
-// The first section of each PT_LOAD and the first section after PT_GNU_RELRO
-// have to be page aligned so that the dynamic linker can set the permissions.
+// The first section of each PT_LOAD, the first section in PT_GNU_RELRO and the
+// first section after PT_GNU_RELRO have to be page aligned so that the dynamic
+// linker can set the permissions.
 template <class ELFT> void Writer<ELFT>::fixSectionAlignments() {
   for (const PhdrEntry &P : Phdrs)
     if (P.p_type == PT_LOAD && P.First)
@@ -1282,6 +1297,8 @@ template <class ELFT> void Writer<ELFT>::fixSectionAlignments() {
   for (const PhdrEntry &P : Phdrs) {
     if (P.p_type != PT_GNU_RELRO)
       continue;
+    if (P.First)
+      P.First->PageAlign = true;
     // Find the first section after PT_GNU_RELRO. If it is in a PT_LOAD we
     // have to align it to a page.
     auto End = OutputSections.end();
@@ -1635,10 +1652,12 @@ static void unlinkAsync(StringRef Path) {
   // Path as a new file. If we do that in a different thread, the new
   // thread can remove the new file.
   SmallString<128> TempPath;
-  if (auto EC = sys::fs::createUniqueFile(Path + "tmp%%%%%%%%", TempPath))
-    fatal(EC, "createUniqueFile failed");
-  if (auto EC = sys::fs::rename(Path, TempPath))
-    fatal(EC, "rename failed");
+  if (sys::fs::createUniqueFile(Path + "tmp%%%%%%%%", TempPath))
+    return;
+  if (sys::fs::rename(Path, TempPath)) {
+    sys::fs::remove(TempPath);
+    return;
+  }
 
   // Remove TempPath in background.
   std::thread([=] { ::remove(TempPath.str().str().c_str()); }).detach();