4 files changed, 13 insertions, 7 deletions
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 2b56e2a..e142ac1 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -8,7 +8,6 @@
 
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index b1dced7..e7c0d37 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -447,10 +447,17 @@ static void emitOneV5FileEntry(MCStreamer *MCOS, const MCDwarfFile &DwarfFile,
         StringRef(reinterpret_cast<const char *>(Cksum.data()), Cksum.size()));
   }
   if (HasAnySource) {
+    // From https://dwarfstd.org/issues/180201.1.html
+    // * The value is an empty null-terminated string if no source is available
+    StringRef Source = DwarfFile.Source.value_or(StringRef());
+    // * If the source is available but is an empty file then the value is a
+    // null-terminated single "\n".
+    if (DwarfFile.Source && DwarfFile.Source->empty())
+      Source = "\n";
     if (LineStr)
-      LineStr->emitRef(MCOS, DwarfFile.Source.value_or(StringRef()));
+      LineStr->emitRef(MCOS, Source);
     else {
-      MCOS->emitBytes(DwarfFile.Source.value_or(StringRef())); // Source and...
+      MCOS->emitBytes(Source);             // Source and...
       MCOS->emitBytes(StringRef("\0", 1)); // its null terminator.
     }
   }
diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 7560399..8c3332c 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -7,7 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/MachO.h"
@@ -478,7 +477,8 @@ void MCMachOStreamer::finalizeCGProfile() {
   // and set its size now so that it's accounted for in layout.
   MCSection *CGProfileSection = Asm.getContext().getMachOSection(
       "__LLVM", "__cg_profile", 0, SectionKind::getMetadata());
-  changeSection(CGProfileSection);
+  // Call the base class changeSection to omit the linker-local label.
+  MCObjectStreamer::changeSection(CGProfileSection);
   // For each entry, reserve space for 2 32-bit indices and a 64-bit count.
   size_t SectionBytes =
       W.getCGProfile().size() * (2 * sizeof(uint32_t) + sizeof(uint64_t));
@@ -510,7 +510,8 @@ void MCMachOStreamer::createAddrSigSection() {
   // to be computed immediately after in order for it to be exported correctly.
   MCSection *AddrSigSection =
       Asm.getContext().getObjectFileInfo()->getAddrSigSection();
-  changeSection(AddrSigSection);
+  // Call the base class changeSection to omit the linker-local label.
+  MCObjectStreamer::changeSection(AddrSigSection);
   auto *Frag = cast<MCFragment>(AddrSigSection->curFragList()->Head);
   // We will generate a series of pointer-sized symbol relocations at offset
   // 0x0. Set the section size to be large enough to contain a single pointer
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 42f4cf4..89f4da5 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -19,7 +19,6 @@
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbol.h"
-#include "llvm/MC/MCValue.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/SourceMgr.h"
 using namespace llvm;