1 files changed, 61 insertions, 9 deletions

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 6eed99db3d7..492b81c1fa7 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -20,6 +20,8 @@
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
+#include "Target.h"
+#include "Threads.h"
 #include "Writer.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
@@ -198,6 +200,15 @@ bool OutputSectionCommand::classof(const BaseCommand *C) {
   return C->Kind == OutputSectionKind;
 }
 
+// Fill [Buf, Buf + Size) with Filler.
+// This is used for linker script "=fillexp" command.
+static void fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
+  size_t I = 0;
+  for (; I + 4 < Size; I += 4)
+    memcpy(Buf + I, &Filler, 4);
+  memcpy(Buf + I, &Filler, Size - I);
+}
+
 bool InputSectionDescription::classof(const BaseCommand *C) {
   return C->Kind == InputSectionKind;
 }
@@ -1032,10 +1043,12 @@ OutputSectionCommand *LinkerScript::getCmd(OutputSection *Sec) const {
   return I->second;
 }
 
-Optional<uint32_t> LinkerScript::getFiller(OutputSection *Sec) {
-  if (OutputSectionCommand *Cmd = getCmd(Sec))
-    return Cmd->Filler;
-  return None;
+uint32_t OutputSectionCommand::getFiller() {
+  if (Filler)
+    return *Filler;
+  if (Sec->Flags & SHF_EXECINSTR)
+    return Target->TrapInstr;
+  return 0;
 }
 
 static void writeInt(uint8_t *Buf, uint64_t Data, uint64_t Size) {
@@ -1051,11 +1064,45 @@ static void writeInt(uint8_t *Buf, uint64_t Data, uint64_t Size) {
     llvm_unreachable("unsupported Size argument");
 }
 
-void LinkerScript::writeDataBytes(OutputSection *Sec, uint8_t *Buf) {
-  if (OutputSectionCommand *Cmd = getCmd(Sec))
-    for (BaseCommand *Base : Cmd->Commands)
-      if (auto *Data = dyn_cast<BytesDataCommand>(Base))
-        writeInt(Buf + Data->Offset, Data->Expression().getValue(), Data->Size);
+template <class ELFT> void OutputSectionCommand::writeTo(uint8_t *Buf) {
+  Sec->Loc = Buf;
+
+  // We may have already rendered compressed content when using
+  // -compress-debug-sections option. Write it together with header.
+  if (!Sec->CompressedData.empty()) {
+    memcpy(Buf, Sec->ZDebugHeader.data(), Sec->ZDebugHeader.size());
+    memcpy(Buf + Sec->ZDebugHeader.size(), Sec->CompressedData.data(),
+           Sec->CompressedData.size());
+    return;
+  }
+
+  // Write leading padding.
+  ArrayRef<InputSection *> Sections = Sec->Sections;
+  uint32_t Filler = getFiller();
+  if (Filler)
+    fill(Buf, Sections.empty() ? Sec->Size : Sections[0]->OutSecOff, Filler);
+
+  parallelForEachN(0, Sections.size(), [=](size_t I) {
+    InputSection *IS = Sections[I];
+    IS->writeTo<ELFT>(Buf);
+
+    // Fill gaps between sections.
+    if (Filler) {
+      uint8_t *Start = Buf + IS->OutSecOff + IS->getSize();
+      uint8_t *End;
+      if (I + 1 == Sections.size())
+        End = Buf + Sec->Size;
+      else
+        End = Buf + Sections[I + 1]->OutSecOff;
+      fill(Start, End - Start, Filler);
+    }
+  });
+
+  // Linker scripts may have BYTE()-family commands with which you
+  // can write arbitrary bytes to the output. Process them if any.
+  for (BaseCommand *Base : Commands)
+    if (auto *Data = dyn_cast<BytesDataCommand>(Base))
+      writeInt(Buf + Data->Offset, Data->Expression().getValue(), Data->Size);
 }
 
 bool LinkerScript::hasLMA(OutputSection *Sec) {
@@ -1102,3 +1149,8 @@ size_t LinkerScript::getPhdrIndex(const Twine &Loc, StringRef PhdrName) {
   error(Loc + ": section header '" + PhdrName + "' is not listed in PHDRS");
   return 0;
 }
+
+template void OutputSectionCommand::writeTo<ELF32LE>(uint8_t *Buf);
+template void OutputSectionCommand::writeTo<ELF32BE>(uint8_t *Buf);
+template void OutputSectionCommand::writeTo<ELF64LE>(uint8_t *Buf);
+template void OutputSectionCommand::writeTo<ELF64BE>(uint8_t *Buf);