Index: lld/trunk/COFF/PDB.cpp
===================================================================
--- lld/trunk/COFF/PDB.cpp
+++ lld/trunk/COFF/PDB.cpp
@@ -211,6 +211,10 @@
   /// PDB.
   DebugChecksumsSubsectionRef Checksums;
 
+  /// The DEBUG_S_INLINEELINES subsection. There can be only one of these per
+  /// object file.
+  DebugInlineeLinesSubsectionRef InlineeLines;
+
   /// The DEBUG_S_FRAMEDATA subsection(s).  There can be more than one of
   /// these and they need not appear in any specific order.  However, they
   /// contain string table references which need to be re-written, so we
@@ -231,6 +235,10 @@
       : Linker(Linker), File(File), IndexMap(IndexMap) {}
 
   void handleDebugS(lld::coff::SectionChunk &DebugS);
+
+  std::shared_ptr<DebugInlineeLinesSubsection>
+  mergeInlineeLines(DebugChecksumsSubsection *NewChecksums);
+
   void finish();
 };
 }
@@ -1004,6 +1012,11 @@
       // modification because the file checksum offsets will stay the same.
       File.ModuleDBI->addDebugSubsection(SS);
       break;
+    case DebugSubsectionKind::InlineeLines:
+      assert(!InlineeLines.valid() &&
+             "Encountered multiple inlinee lines subsections!");
+      ExitOnErr(InlineeLines.initialize(SS.getRecordData()));
+      break;
     case DebugSubsectionKind::FrameData: {
       // We need to re-write string table indices here, so save off all
       // frame data subsections until we've processed the entire list of
@@ -1018,13 +1031,77 @@
                                 SS.getRecordData());
       break;
     }
+
+    case DebugSubsectionKind::CrossScopeImports:
+    case DebugSubsectionKind::CrossScopeExports:
+      // These appear to relate to cross-module optimization, so we might use
+      // these for ThinLTO.
+      break;
+
+    case DebugSubsectionKind::ILLines:
+    case DebugSubsectionKind::FuncMDTokenMap:
+    case DebugSubsectionKind::TypeMDTokenMap:
+    case DebugSubsectionKind::MergedAssemblyInput:
+      // These appear to relate to .Net assembly info.
+      break;
+
+    case DebugSubsectionKind::CoffSymbolRVA:
+      // Unclear what this is for.
+      break;
+
     default:
-      // FIXME: Process the rest of the subsections.
+      warn("ignoring unknown debug$S subsection kind 0x" +
+           utohexstr(uint32_t(SS.kind())));
       break;
     }
   }
 }
 
+static Expected<StringRef>
+getFileName(const DebugStringTableSubsectionRef &Strings,
+            const DebugChecksumsSubsectionRef &Checksums, uint32_t FileID) {
+  auto Iter = Checksums.getArray().at(FileID);
+  if (Iter == Checksums.getArray().end())
+    return make_error<CodeViewError>(cv_error_code::no_records);
+  uint32_t Offset = Iter->FileNameOffset;
+  return Strings.getString(Offset);
+}
+
+std::shared_ptr<DebugInlineeLinesSubsection>
+DebugSHandler::mergeInlineeLines(DebugChecksumsSubsection *NewChecksums) {
+  auto NewInlineeLines = std::make_shared<DebugInlineeLinesSubsection>(
+      *NewChecksums, InlineeLines.hasExtraFiles());
+
+  for (const InlineeSourceLine &Line : InlineeLines) {
+    TypeIndex Inlinee = Line.Header->Inlinee;
+    uint32_t FileID = Line.Header->FileID;
+    uint32_t SourceLine = Line.Header->SourceLineNum;
+
+    ArrayRef<TypeIndex> TypeOrItemMap =
+        IndexMap.IsTypeServerMap ? IndexMap.IPIMap : IndexMap.TPIMap;
+    if (!remapTypeIndex(Inlinee, TypeOrItemMap)) {
+      log("ignoring inlinee line record in " + File.getName() +
+          " with bad inlinee index 0x" + utohexstr(Inlinee.getIndex()));
+      continue;
+    }
+
+    SmallString<128> Filename =
+        ExitOnErr(getFileName(CVStrTab, Checksums, FileID));
+    pdbMakeAbsolute(Filename);
+    NewInlineeLines->addInlineSite(Inlinee, Filename, SourceLine);
+
+    if (InlineeLines.hasExtraFiles()) {
+      for (uint32_t ExtraFileId : Line.ExtraFiles) {
+        Filename = ExitOnErr(getFileName(CVStrTab, Checksums, ExtraFileId));
+        pdbMakeAbsolute(Filename);
+        NewInlineeLines->addExtraFile(Filename);
+      }
+    }
+  }
+
+  return NewInlineeLines;
+}
+
 void DebugSHandler::finish() {
   pdb::DbiStreamBuilder &DbiBuilder = Linker.Builder.getDbiBuilder();
 
@@ -1063,13 +1140,17 @@
   // subsections.
   auto NewChecksums = make_unique<DebugChecksumsSubsection>(Linker.PDBStrTab);
   for (FileChecksumEntry &FC : Checksums) {
-    SmallString<128> FileName =
+    SmallString<128> Filename =
         ExitOnErr(CVStrTab.getString(FC.FileNameOffset));
-    pdbMakeAbsolute(FileName);
-    ExitOnErr(Linker.Builder.getDbiBuilder().addModuleSourceFile(
-        *File.ModuleDBI, FileName));
-    NewChecksums->addChecksum(FileName, FC.Kind, FC.Checksum);
+    pdbMakeAbsolute(Filename);
+    ExitOnErr(DbiBuilder.addModuleSourceFile(*File.ModuleDBI, Filename));
+    NewChecksums->addChecksum(Filename, FC.Kind, FC.Checksum);
   }
+
+  // Rewrite inlinee item indices if present.
+  if (InlineeLines.valid())
+    File.ModuleDBI->addDebugSubsection(mergeInlineeLines(NewChecksums.get()));
+
   File.ModuleDBI->addDebugSubsection(std::move(NewChecksums));
 }
 
@@ -1604,16 +1685,6 @@
   ExitOnErr(Builder.commit(Config->PDBPath, Guid));
 }
 
-static Expected<StringRef>
-getFileName(const DebugStringTableSubsectionRef &Strings,
-            const DebugChecksumsSubsectionRef &Checksums, uint32_t FileID) {
-  auto Iter = Checksums.getArray().at(FileID);
-  if (Iter == Checksums.getArray().end())
-    return make_error<CodeViewError>(cv_error_code::no_records);
-  uint32_t Offset = Iter->FileNameOffset;
-  return Strings.getString(Offset);
-}
-
 static uint32_t getSecrelReloc() {
   switch (Config->Machine) {
   case AMD64:
Index: lld/trunk/test/COFF/pdb-inlinees-extrafiles.s
===================================================================
--- lld/trunk/test/COFF/pdb-inlinees-extrafiles.s
+++ lld/trunk/test/COFF/pdb-inlinees-extrafiles.s
@@ -0,0 +1,334 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj %s -o %t.obj -triple x86_64-windows-msvc
+# RUN: lld-link -entry:main -nodefaultlib %t.obj -out:%t.exe -pdb:%t.pdb -debug
+# RUN: llvm-pdbutil dump -il %t.pdb | FileCheck %s
+
+# The assembly was hand written to model the following C code. As of this
+# writing, clang does not emit extra files for inlinees, so it had to be hand
+# written.
+
+# // t1.h:
+# ++x;
+# #include "t2.h"
+# ++x;
+
+# // t2.h:
+# ++x;
+# __debugbreak();
+# ++x;
+
+# // t.c:
+# volatile int x;
+# static __forceinline void inlinee_1(void) {
+#   ++x;
+# #include "t1.inc"
+#   ++x;
+# }
+# int main() {
+#   ++x;
+#   inlinee_1();
+#   ++x;
+#   return x;
+# }
+
+# CHECK:                             Inlinee Lines
+# CHECK:      Mod 0000 | `{{.*}}pdb-inlinees-extrafiles.s.tmp.obj`:
+# CHECK-NEXT:  Inlinee |  Line | Source File
+# CHECK-NEXT:   0x1000 |     7 | C:\src\llvm-project\build\t.c (MD5: A79D837C976E9F0463A474D74E2EE9E7)
+# CHECK-NEXT:                    C:\src\llvm-project\build\t1.h (MD5: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
+# CHECK-NEXT:                    C:\src\llvm-project\build\t2.h (MD5: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
+
+	.text
+	.def	 @feat.00;
+	.scl	3;
+	.type	0;
+	.endef
+	.globl	@feat.00
+.set @feat.00, 0
+	.intel_syntax noprefix
+	.file	"t.c"
+	.def	 main;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,main
+	.globl	main                    # -- Begin function main
+main:                                   # @main
+.Lfunc_begin0:
+	.cv_func_id 0
+# %bb.0:                                # %entry
+	.cv_file	1 "C:\\src\\llvm-project\\build\\t.c" "A79D837C976E9F0463A474D74E2EE9E7" 1
+	.cv_file	2 "C:\\src\\llvm-project\\build\\t1.h" "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" 1
+	.cv_file	3 "C:\\src\\llvm-project\\build\\t2.h" "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" 1
+	.cv_loc	0 1 13 0                # t.c:13:0
+	inc	dword ptr [rip + x]
+.Ltmp0:
+	.cv_inline_site_id 1 within 0 inlined_at 1 14 0
+	.cv_loc	1 1 3 0                 # t.c:3:0
+	inc	dword ptr [rip + x]
+.Ltmp1:
+	.cv_loc	1 2 1 0                 # t1.h:1:0
+	inc	dword ptr [rip + x]
+	.cv_loc	1 3 1 0                 # t2.h:1:0
+	inc	dword ptr [rip + x]
+	.cv_loc	1 3 2 0                 # t2.h:2:0
+	int3
+	.cv_loc	1 3 3 0                 # t2.h:3:0
+	inc	dword ptr [rip + x]
+	.cv_loc	1 2 3 0                 # t1.h:3:0
+	inc	dword ptr [rip + x]
+.Ltmp2:
+	.cv_loc	1 1 5 0                # t.c:5:0
+	inc	dword ptr [rip + x]
+.Ltmp3:
+	.cv_loc	0 1 15 0                # t.c:15:0
+	inc	dword ptr [rip + x]
+	.cv_loc	0 1 16 0                # t.c:16:0
+	mov	eax, dword ptr [rip + x]
+	ret
+.Ltmp4:
+.Lfunc_end0:
+                                        # -- End function
+	.comm	x,4,2                   # @x
+	.section	.debug$S,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	241
+	.long	.Ltmp6-.Ltmp5           # Subsection size
+.Ltmp5:
+	.short	.Ltmp8-.Ltmp7           # Record length
+.Ltmp7:
+	.short	4412                    # Record kind: S_COMPILE3
+	.long	0                       # Flags and language
+	.short	208                     # CPUType
+	.short	9                       # Frontend version
+	.short	0
+	.short	0
+	.short	0
+	.short	9000                    # Backend version
+	.short	0
+	.short	0
+	.short	0
+	.asciz	"clang version 9.0.0 (git@github.com:llvm/llvm-project.git aa762a56caf3ef2b0b41c501e66d3ef32903a2d0)" # Null-terminated compiler version string
+	.p2align	2
+.Ltmp8:
+.Ltmp6:
+	.p2align	2
+	.long	246                     # Inlinee lines subsection
+	.long	.Ltmp10-.Ltmp9          # Subsection size
+.Ltmp9:
+	.long	1                       # Inlinee lines signature, extra files
+
+                                        # Inlined function inlinee_1 starts at t.c:7
+	.long	4098                    # Type index of inlined function
+	.cv_filechecksumoffset	1       # Offset into filechecksum table
+	.long	7                       # Starting line number
+	.long 2
+	.cv_filechecksumoffset	2       # Offset into filechecksum table
+	.cv_filechecksumoffset	3       # Offset into filechecksum table
+
+.Ltmp10:
+	.p2align	2
+	.section	.debug$S,"dr",associative,main
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	241                     # Symbol subsection for main
+	.long	.Ltmp12-.Ltmp11         # Subsection size
+.Ltmp11:
+	.short	.Ltmp14-.Ltmp13         # Record length
+.Ltmp13:
+	.short	4423                    # Record kind: S_GPROC32_ID
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	0                       # PtrNext
+	.long	.Lfunc_end0-main        # Code size
+	.long	0                       # Offset after prologue
+	.long	0                       # Offset before epilogue
+	.long	4101                    # Function type index
+	.secrel32	main            # Function section relative address
+	.secidx	main                    # Function section index
+	.byte	0                       # Flags
+	.asciz	"main"                  # Function name
+	.p2align	2
+.Ltmp14:
+	.short	.Ltmp16-.Ltmp15         # Record length
+.Ltmp15:
+	.short	4114                    # Record kind: S_FRAMEPROC
+	.long	0                       # FrameSize
+	.long	0                       # Padding
+	.long	0                       # Offset of padding
+	.long	0                       # Bytes of callee saved registers
+	.long	0                       # Exception handler offset
+	.short	0                       # Exception handler section
+	.long	0                       # Flags (defines frame register)
+	.p2align	2
+.Ltmp16:
+	.short	.Ltmp18-.Ltmp17         # Record length
+.Ltmp17:
+	.short	4429                    # Record kind: S_INLINESITE
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	4098                    # Inlinee type index
+	.cv_inline_linetable	1 1 7 .Lfunc_begin0 .Lfunc_end0
+	.p2align	2
+.Ltmp18:
+	.short	2                       # Record length
+	.short	4430                    # Record kind: S_INLINESITE_END
+	.short	2                       # Record length
+	.short	4431                    # Record kind: S_PROC_ID_END
+.Ltmp12:
+	.p2align	2
+	.cv_linetable	0, main, .Lfunc_end0
+	.section	.debug$S,"dr"
+	.long	241                     # Symbol subsection for globals
+	.long	.Ltmp22-.Ltmp21         # Subsection size
+.Ltmp21:
+	.short	.Ltmp24-.Ltmp23         # Record length
+.Ltmp23:
+	.short	4365                    # Record kind: S_GDATA32
+	.long	4102                    # Type
+	.secrel32	x               # DataOffset
+	.secidx	x                       # Segment
+	.asciz	"x"                     # Name
+	.p2align	2
+.Ltmp24:
+.Ltmp22:
+	.p2align	2
+	.cv_filechecksums               # File index to string table offset subsection
+	.cv_stringtable                 # String table
+	.long	241
+	.long	.Ltmp26-.Ltmp25         # Subsection size
+.Ltmp25:
+	.short	.Ltmp28-.Ltmp27         # Record length
+.Ltmp27:
+	.short	4428                    # Record kind: S_BUILDINFO
+	.long	4105                    # LF_BUILDINFO index
+	.p2align	2
+.Ltmp28:
+.Ltmp26:
+	.p2align	2
+	.section	.debug$T,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	# ArgList (0x1000) {
+	#   TypeLeafKind: LF_ARGLIST (0x1201)
+	#   NumArgs: 0
+	#   Arguments [
+	#   ]
+	# }
+	.byte	0x06, 0x00, 0x01, 0x12
+	.byte	0x00, 0x00, 0x00, 0x00
+	# Procedure (0x1001) {
+	#   TypeLeafKind: LF_PROCEDURE (0x1008)
+	#   ReturnType: void (0x3)
+	#   CallingConvention: NearC (0x0)
+	#   FunctionOptions [ (0x0)
+	#   ]
+	#   NumParameters: 0
+	#   ArgListType: () (0x1000)
+	# }
+	.byte	0x0e, 0x00, 0x08, 0x10
+	.byte	0x03, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x10, 0x00, 0x00
+	# FuncId (0x1002) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: inlinee_1
+	# }
+	.byte	0x16, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x69, 0x6e, 0x6c, 0x69
+	.byte	0x6e, 0x65, 0x65, 0x5f
+	.byte	0x31, 0x00, 0xf2, 0xf1
+	# FuncId (0x1003) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: inlinee_2
+	# }
+	.byte	0x16, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x69, 0x6e, 0x6c, 0x69
+	.byte	0x6e, 0x65, 0x65, 0x5f
+	.byte	0x32, 0x00, 0xf2, 0xf1
+	# Procedure (0x1004) {
+	#   TypeLeafKind: LF_PROCEDURE (0x1008)
+	#   ReturnType: int (0x74)
+	#   CallingConvention: NearC (0x0)
+	#   FunctionOptions [ (0x0)
+	#   ]
+	#   NumParameters: 0
+	#   ArgListType: () (0x1000)
+	# }
+	.byte	0x0e, 0x00, 0x08, 0x10
+	.byte	0x74, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x10, 0x00, 0x00
+	# FuncId (0x1005) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: int () (0x1004)
+	#   Name: main
+	# }
+	.byte	0x12, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x04, 0x10, 0x00, 0x00
+	.byte	0x6d, 0x61, 0x69, 0x6e
+	.byte	0x00, 0xf3, 0xf2, 0xf1
+	# Modifier (0x1006) {
+	#   TypeLeafKind: LF_MODIFIER (0x1001)
+	#   ModifiedType: int (0x74)
+	#   Modifiers [ (0x2)
+	#     Volatile (0x2)
+	#   ]
+	# }
+	.byte	0x0a, 0x00, 0x01, 0x10
+	.byte	0x74, 0x00, 0x00, 0x00
+	.byte	0x02, 0x00, 0xf2, 0xf1
+	# StringId (0x1007) {
+	#   TypeLeafKind: LF_STRING_ID (0x1605)
+	#   Id: 0x0
+	#   StringData: C:\src\llvm-project\build
+	# }
+	.byte	0x22, 0x00, 0x05, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x43, 0x3a, 0x5c, 0x73
+	.byte	0x72, 0x63, 0x5c, 0x6c
+	.byte	0x6c, 0x76, 0x6d, 0x2d
+	.byte	0x70, 0x72, 0x6f, 0x6a
+	.byte	0x65, 0x63, 0x74, 0x5c
+	.byte	0x62, 0x75, 0x69, 0x6c
+	.byte	0x64, 0x00, 0xf2, 0xf1
+	# StringId (0x1008) {
+	#   TypeLeafKind: LF_STRING_ID (0x1605)
+	#   Id: 0x0
+	#   StringData: t.c
+	# }
+	.byte	0x0a, 0x00, 0x05, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x74, 0x2e, 0x63, 0x00
+	# BuildInfo (0x1009) {
+	#   TypeLeafKind: LF_BUILDINFO (0x1603)
+	#   NumArgs: 5
+	#   Arguments [
+	#     ArgType: C:\src\llvm-project\build (0x1007)
+	#     ArgType: 0x0
+	#     ArgType: t.c (0x1008)
+	#     ArgType: 0x0
+	#     ArgType: 0x0
+	#   ]
+	# }
+	.byte	0x1a, 0x00, 0x03, 0x16
+	.byte	0x05, 0x00, 0x07, 0x10
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x08, 0x10
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0xf2, 0xf1
+
+	.addrsig
+	.addrsig_sym x
Index: lld/trunk/test/COFF/pdb-inlinees.s
===================================================================
--- lld/trunk/test/COFF/pdb-inlinees.s
+++ lld/trunk/test/COFF/pdb-inlinees.s
@@ -0,0 +1,332 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj %s -o %t.obj -triple x86_64-windows-msvc
+# RUN: lld-link -entry:main -nodefaultlib %t.obj -out:%t.exe -pdb:%t.pdb -debug
+# RUN: llvm-pdbutil dump -il %t.pdb | FileCheck %s
+
+# Compiled from this C code, with modifications to test multiple file checksums:
+# volatile int x;
+# static __forceinline void inlinee_2(void) {
+#   ++x;
+#   __debugbreak();
+#   ++x;
+# }
+# static __forceinline void inlinee_1(void) {
+#   ++x;
+#   inlinee_2();
+#   ++x;
+# }
+# int main() {
+#   ++x;
+#   inlinee_1();
+#   ++x;
+#   return x;
+# }
+
+# CHECK:                             Inlinee Lines
+# CHECK:      Mod 0000 | `{{.*}}pdb-inlinees.s.tmp.obj`:
+# CHECK-NEXT:  Inlinee |  Line | Source File
+# CHECK-NEXT:   0x1000 |     7 | C:\src\llvm-project\build\t.c (MD5: A79D837C976E9F0463A474D74E2EE9E7)
+# CHECK-NEXT:   0x1001 |     2 | C:\src\llvm-project\build\file2.h (MD5: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
+
+	.text
+	.def	 @feat.00;
+	.scl	3;
+	.type	0;
+	.endef
+	.globl	@feat.00
+.set @feat.00, 0
+	.intel_syntax noprefix
+	.file	"t.c"
+	.def	 main;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,main
+	.globl	main                    # -- Begin function main
+main:                                   # @main
+.Lfunc_begin0:
+	.cv_func_id 0
+# %bb.0:                                # %entry
+	.cv_file	1 "C:\\src\\llvm-project\\build\\t.c" "A79D837C976E9F0463A474D74E2EE9E7" 1
+	.cv_file	2 "C:\\src\\llvm-project\\build\\file2.h" "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" 1
+	.cv_loc	0 1 13 0                # t.c:13:0
+	inc	dword ptr [rip + x]
+.Ltmp0:
+	.cv_inline_site_id 1 within 0 inlined_at 1 14 0
+	.cv_loc	1 1 8 0                 # t.c:8:0
+	inc	dword ptr [rip + x]
+.Ltmp1:
+	.cv_inline_site_id 2 within 1 inlined_at 1 9 0
+	.cv_loc	2 2 3 0                 # file2.h:3:0
+	inc	dword ptr [rip + x]
+	.cv_loc	2 2 4 0                 # file2.h:4:0
+	int3
+	.cv_loc	2 2 5 0                 # file2.h:5:0
+	inc	dword ptr [rip + x]
+.Ltmp2:
+	.cv_loc	1 1 10 0                # t.c:10:0
+	inc	dword ptr [rip + x]
+.Ltmp3:
+	.cv_loc	0 1 15 0                # t.c:15:0
+	inc	dword ptr [rip + x]
+	.cv_loc	0 1 16 0                # t.c:16:0
+	mov	eax, dword ptr [rip + x]
+	ret
+.Ltmp4:
+.Lfunc_end0:
+                                        # -- End function
+	.comm	x,4,2                   # @x
+	.section	.debug$S,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	241
+	.long	.Ltmp6-.Ltmp5           # Subsection size
+.Ltmp5:
+	.short	.Ltmp8-.Ltmp7           # Record length
+.Ltmp7:
+	.short	4412                    # Record kind: S_COMPILE3
+	.long	0                       # Flags and language
+	.short	208                     # CPUType
+	.short	9                       # Frontend version
+	.short	0
+	.short	0
+	.short	0
+	.short	9000                    # Backend version
+	.short	0
+	.short	0
+	.short	0
+	.asciz	"clang version 9.0.0 (git@github.com:llvm/llvm-project.git aa762a56caf3ef2b0b41c501e66d3ef32903a2d0)" # Null-terminated compiler version string
+	.p2align	2
+.Ltmp8:
+.Ltmp6:
+	.p2align	2
+	.long	246                     # Inlinee lines subsection
+	.long	.Ltmp10-.Ltmp9          # Subsection size
+.Ltmp9:
+	.long	0                       # Inlinee lines signature
+
+                                        # Inlined function inlinee_1 starts at t.c:7
+	.long	4098                    # Type index of inlined function
+	.cv_filechecksumoffset	1       # Offset into filechecksum table
+	.long	7                       # Starting line number
+
+                                        # Inlined function inlinee_2 starts at file2.h:2
+	.long	4099                    # Type index of inlined function
+	.cv_filechecksumoffset	2       # Offset into filechecksum table
+	.long	2                       # Starting line number
+.Ltmp10:
+	.p2align	2
+	.section	.debug$S,"dr",associative,main
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	241                     # Symbol subsection for main
+	.long	.Ltmp12-.Ltmp11         # Subsection size
+.Ltmp11:
+	.short	.Ltmp14-.Ltmp13         # Record length
+.Ltmp13:
+	.short	4423                    # Record kind: S_GPROC32_ID
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	0                       # PtrNext
+	.long	.Lfunc_end0-main        # Code size
+	.long	0                       # Offset after prologue
+	.long	0                       # Offset before epilogue
+	.long	4101                    # Function type index
+	.secrel32	main            # Function section relative address
+	.secidx	main                    # Function section index
+	.byte	0                       # Flags
+	.asciz	"main"                  # Function name
+	.p2align	2
+.Ltmp14:
+	.short	.Ltmp16-.Ltmp15         # Record length
+.Ltmp15:
+	.short	4114                    # Record kind: S_FRAMEPROC
+	.long	0                       # FrameSize
+	.long	0                       # Padding
+	.long	0                       # Offset of padding
+	.long	0                       # Bytes of callee saved registers
+	.long	0                       # Exception handler offset
+	.short	0                       # Exception handler section
+	.long	0                       # Flags (defines frame register)
+	.p2align	2
+.Ltmp16:
+	.short	.Ltmp18-.Ltmp17         # Record length
+.Ltmp17:
+	.short	4429                    # Record kind: S_INLINESITE
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	4098                    # Inlinee type index
+	.cv_inline_linetable	1 1 7 .Lfunc_begin0 .Lfunc_end0
+	.p2align	2
+.Ltmp18:
+	.short	.Ltmp20-.Ltmp19         # Record length
+.Ltmp19:
+	.short	4429                    # Record kind: S_INLINESITE
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	4099                    # Inlinee type index
+	.cv_inline_linetable	2 2 2 .Lfunc_begin0 .Lfunc_end0
+	.p2align	2
+.Ltmp20:
+	.short	2                       # Record length
+	.short	4430                    # Record kind: S_INLINESITE_END
+	.short	2                       # Record length
+	.short	4430                    # Record kind: S_INLINESITE_END
+	.short	2                       # Record length
+	.short	4431                    # Record kind: S_PROC_ID_END
+.Ltmp12:
+	.p2align	2
+	.cv_linetable	0, main, .Lfunc_end0
+	.section	.debug$S,"dr"
+	.long	241                     # Symbol subsection for globals
+	.long	.Ltmp22-.Ltmp21         # Subsection size
+.Ltmp21:
+	.short	.Ltmp24-.Ltmp23         # Record length
+.Ltmp23:
+	.short	4365                    # Record kind: S_GDATA32
+	.long	4102                    # Type
+	.secrel32	x               # DataOffset
+	.secidx	x                       # Segment
+	.asciz	"x"                     # Name
+	.p2align	2
+.Ltmp24:
+.Ltmp22:
+	.p2align	2
+	.cv_filechecksums               # File index to string table offset subsection
+	.cv_stringtable                 # String table
+	.long	241
+	.long	.Ltmp26-.Ltmp25         # Subsection size
+.Ltmp25:
+	.short	.Ltmp28-.Ltmp27         # Record length
+.Ltmp27:
+	.short	4428                    # Record kind: S_BUILDINFO
+	.long	4105                    # LF_BUILDINFO index
+	.p2align	2
+.Ltmp28:
+.Ltmp26:
+	.p2align	2
+	.section	.debug$T,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	# ArgList (0x1000) {
+	#   TypeLeafKind: LF_ARGLIST (0x1201)
+	#   NumArgs: 0
+	#   Arguments [
+	#   ]
+	# }
+	.byte	0x06, 0x00, 0x01, 0x12
+	.byte	0x00, 0x00, 0x00, 0x00
+	# Procedure (0x1001) {
+	#   TypeLeafKind: LF_PROCEDURE (0x1008)
+	#   ReturnType: void (0x3)
+	#   CallingConvention: NearC (0x0)
+	#   FunctionOptions [ (0x0)
+	#   ]
+	#   NumParameters: 0
+	#   ArgListType: () (0x1000)
+	# }
+	.byte	0x0e, 0x00, 0x08, 0x10
+	.byte	0x03, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x10, 0x00, 0x00
+	# FuncId (0x1002) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: inlinee_1
+	# }
+	.byte	0x16, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x69, 0x6e, 0x6c, 0x69
+	.byte	0x6e, 0x65, 0x65, 0x5f
+	.byte	0x31, 0x00, 0xf2, 0xf1
+	# FuncId (0x1003) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: inlinee_2
+	# }
+	.byte	0x16, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x69, 0x6e, 0x6c, 0x69
+	.byte	0x6e, 0x65, 0x65, 0x5f
+	.byte	0x32, 0x00, 0xf2, 0xf1
+	# Procedure (0x1004) {
+	#   TypeLeafKind: LF_PROCEDURE (0x1008)
+	#   ReturnType: int (0x74)
+	#   CallingConvention: NearC (0x0)
+	#   FunctionOptions [ (0x0)
+	#   ]
+	#   NumParameters: 0
+	#   ArgListType: () (0x1000)
+	# }
+	.byte	0x0e, 0x00, 0x08, 0x10
+	.byte	0x74, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x10, 0x00, 0x00
+	# FuncId (0x1005) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: int () (0x1004)
+	#   Name: main
+	# }
+	.byte	0x12, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x04, 0x10, 0x00, 0x00
+	.byte	0x6d, 0x61, 0x69, 0x6e
+	.byte	0x00, 0xf3, 0xf2, 0xf1
+	# Modifier (0x1006) {
+	#   TypeLeafKind: LF_MODIFIER (0x1001)
+	#   ModifiedType: int (0x74)
+	#   Modifiers [ (0x2)
+	#     Volatile (0x2)
+	#   ]
+	# }
+	.byte	0x0a, 0x00, 0x01, 0x10
+	.byte	0x74, 0x00, 0x00, 0x00
+	.byte	0x02, 0x00, 0xf2, 0xf1
+	# StringId (0x1007) {
+	#   TypeLeafKind: LF_STRING_ID (0x1605)
+	#   Id: 0x0
+	#   StringData: C:\src\llvm-project\build
+	# }
+	.byte	0x22, 0x00, 0x05, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x43, 0x3a, 0x5c, 0x73
+	.byte	0x72, 0x63, 0x5c, 0x6c
+	.byte	0x6c, 0x76, 0x6d, 0x2d
+	.byte	0x70, 0x72, 0x6f, 0x6a
+	.byte	0x65, 0x63, 0x74, 0x5c
+	.byte	0x62, 0x75, 0x69, 0x6c
+	.byte	0x64, 0x00, 0xf2, 0xf1
+	# StringId (0x1008) {
+	#   TypeLeafKind: LF_STRING_ID (0x1605)
+	#   Id: 0x0
+	#   StringData: t.c
+	# }
+	.byte	0x0a, 0x00, 0x05, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x74, 0x2e, 0x63, 0x00
+	# BuildInfo (0x1009) {
+	#   TypeLeafKind: LF_BUILDINFO (0x1603)
+	#   NumArgs: 5
+	#   Arguments [
+	#     ArgType: C:\src\llvm-project\build (0x1007)
+	#     ArgType: 0x0
+	#     ArgType: t.c (0x1008)
+	#     ArgType: 0x0
+	#     ArgType: 0x0
+	#   ]
+	# }
+	.byte	0x1a, 0x00, 0x03, 0x16
+	.byte	0x05, 0x00, 0x07, 0x10
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x08, 0x10
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0xf2, 0xf1
+
+	.addrsig
+	.addrsig_sym x
Index: lld/trunk/test/COFF/pdb-unknown-subsection.s
===================================================================
--- lld/trunk/test/COFF/pdb-unknown-subsection.s
+++ lld/trunk/test/COFF/pdb-unknown-subsection.s
@@ -0,0 +1,46 @@
+# Check that unknown symbol subsections are ignored with a warning, and a PDB
+# is produced anyway.
+
+# REQUIRES: x86
+# RUN: llvm-mc -triple=i386-pc-win32 -filetype=obj -o %t.obj %s
+# RUN: lld-link -subsystem:console -debug -nodefaultlib -entry:foo -out:%t.exe -pdb:%t.pdb %t.obj 2>&1 | FileCheck %s --check-prefix=WARNING
+# RUN: llvm-pdbutil dump -symbols %t.pdb | FileCheck %s
+
+# WARNING: ignoring unknown debug$S subsection kind 0xFF
+
+# CHECK:                           Symbols
+# CHECK:        4 | S_COMPILE3 [size = 52]
+# CHECK:            machine = intel x86-x64, Ver = clang version SENTINEL, language = c
+
+.text
+_foo:
+ret
+
+.global _foo
+
+.section .debug$S,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	0xF1 # Symbol subsection
+	.long	.Ltmp6-.Ltmp5           # Subsection size
+.Ltmp5:
+	.short	.Ltmp8-.Ltmp7           # Record length
+.Ltmp7:
+	.short	4412                    # Record kind: S_COMPILE3
+	.long	0                       # Flags and language
+	.short	208                     # CPUType
+	.short	9                       # Frontend version
+	.short	0
+	.short	0
+	.short	0
+	.short	9000                    # Backend version
+	.short	0
+	.short	0
+	.short	0
+	.asciz	"clang version SENTINEL" # Null-terminated compiler version string
+	.p2align	2
+.Ltmp8:
+.Ltmp6:
+	.long	0xFF # Unknown subsection kind
+	.long	4           # Subsection size
+	.long  0
Index: llvm/trunk/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
===================================================================
--- llvm/trunk/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
+++ llvm/trunk/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
@@ -70,6 +70,11 @@
   }
 
   Error initialize(BinaryStreamReader Reader);
+  Error initialize(BinaryStreamRef Section) {
+    return initialize(BinaryStreamReader(Section));
+  }
+
+  bool valid() const { return Lines.valid(); }
   bool hasExtraFiles() const;
 
   Iterator begin() const { return Lines.begin(); }
@@ -77,7 +82,7 @@
 
 private:
   InlineeLinesSignature Signature;
-  VarStreamArray<InlineeSourceLine> Lines;
+  LinesArray Lines;
 };
 
 class DebugInlineeLinesSubsection final : public DebugSubsection {
Index: llvm/trunk/tools/llvm-pdbutil/DumpOutputStyle.cpp
===================================================================
--- llvm/trunk/tools/llvm-pdbutil/DumpOutputStyle.cpp
+++ llvm/trunk/tools/llvm-pdbutil/DumpOutputStyle.cpp
@@ -995,6 +995,10 @@
           P.formatLine("{0,+8} | {1,+5} | ", Entry.Header->Inlinee,
                        fmtle(Entry.Header->SourceLineNum));
           Strings.formatFromChecksumsOffset(P, Entry.Header->FileID, true);
+          for (const auto &ExtraFileID : Entry.ExtraFiles) {
+            P.formatLine("                   ");
+            Strings.formatFromChecksumsOffset(P, ExtraFileID, true);
+          }
         }
         P.NewLine();
       });