[LLD][COFF] Ignore DEBUG_S_XFGHASH_TYPE/VIRTUAL

These are new debug types that ships with the latest
Windows SDK and would warn and finally fail lld-link.

The symbols seems to be related to Microsoft's XFG
which is their version of CFG. We can't handle any of
this yet, so for now we can just ignore these types
so that lld doesn't fail with a new version of Windows
SDK.

Fixes: #56285

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D129378

(cherry picked from commit 576375a)

Author: tru

lld/COFF/PDB.cpp

@@ -811,6 +811,10 @@ void DebugSHandler::handleDebugS(SectionChunk *debugChunk) {
       // Unclear what this is for.
       break;
 
+    case DebugSubsectionKind::XfgHashType:
+    case DebugSubsectionKind::XfgHashVirtual:
+      break;
+
     default:
       warn("ignoring unknown debug$S subsection kind 0x" +
            utohexstr(uint32_t(ss.kind())) + " in file " + toString(&file));

lld/test/COFF/pdb-unknown-subsection.s

@@ -7,7 +7,7 @@
 # RUN: llvm-pdbutil dump -symbols %t.pdb | FileCheck %s
 
 # WARNING-NOT: ignoring unknown
-# WARNING: ignoring unknown debug$S subsection kind 0xFF
+# WARNING: ignoring unknown debug$S subsection kind 0x1FF
 # WARNING-NOT: ignoring unknown
 
 # CHECK:                           Symbols
@@ -43,7 +43,7 @@ ret
 	.p2align	2
 .Ltmp8:
 .Ltmp6:
-	.long	0xFF # Unknown subsection kind
+	.long	0x1FF # Unknown subsection kind
 	.long	4           # Subsection size
 	.long  0
 	.long	0x800000F1 # Unknown subsection kind

lld/test/COFF/pdb-xfg-section.s

@@ -0,0 +1,47 @@
+// Check that we ignore XFG subsections in CodeView information.
+// This test should be removed if we ever end up adding XFG support to lld.
+
+# REQUIRES: x86
+# RUN: llvm-mc -triple=i386-pc-win32 -filetype=obj -o %t.obj %s
+# RUN: lld-link -verbose -safeseh:no -subsystem:console -debug -nodefaultlib -entry:foo -out:%t.exe -pdb:%t.pdb %t.obj 2>&1 | FileCheck %s
+
+// XFGHashType should not generate a warning
+# CHECK-NOT: ignoring unknown debug$S subsection kind 0xFF
+// XFGHashVirtual should not generate a warning
+# CHECK-NOT: ignoring unknown debug$S subsection kind 0x100
+
+.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 # XFGHashType subsection
+	.long	4           # Subsection size
+	.long  0
+	.long	0x100 # XFGHashVirtual subsection
+	.long	4           # Subsection size
+	.long  0

llvm/include/llvm/DebugInfo/CodeView/CodeView.h

@@ -330,6 +330,9 @@ enum class DebugSubsectionKind : uint32_t {
   MergedAssemblyInput = 0xfc,
 
   CoffSymbolRVA = 0xfd,
+
+  XfgHashType = 0xff,
+  XfgHashVirtual = 0x100,
 };
 
 /// Equivalent to CV_ptrtype_e.

llvm/lib/DebugInfo/PDB/Native/FormatUtil.cpp

@@ -66,6 +66,8 @@ std::string llvm::pdb::formatChunkKind(DebugSubsectionKind Kind,
       RETURN_CASE(DebugSubsectionKind, MergedAssemblyInput,
                   "merged assembly input");
       RETURN_CASE(DebugSubsectionKind, CoffSymbolRVA, "coff symbol rva");
+      RETURN_CASE(DebugSubsectionKind, XfgHashType, "xfg hash type");
+      RETURN_CASE(DebugSubsectionKind, XfgHashVirtual, "xfg hash virtual");
     }
   } else {
     switch (Kind) {
@@ -89,6 +91,11 @@ std::string llvm::pdb::formatChunkKind(DebugSubsectionKind Kind,
                   "DEBUG_S_MERGED_ASSEMBLYINPUT");
       RETURN_CASE(DebugSubsectionKind, CoffSymbolRVA,
                   "DEBUG_S_COFF_SYMBOL_RVA");
+      RETURN_CASE(DebugSubsectionKind, XfgHashType,
+                  "DEBUG_S_XFGHASH_TYPE");
+      RETURN_CASE(DebugSubsectionKind, XfgHashVirtual,
+                  "DEBUG_S_XFGHASH_VIRTUAL");
+
     }
   }
   return formatUnknownEnum(Kind);