Merge commit '9ac059cf46a7' from apple/stable/20200714 into swift/main

Author: git apple-llvm automerger

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

@@ -172,6 +172,15 @@ unsigned DWARFVerifier::verifyUnitContents(DWARFUnit &Unit) {
       NumUnitErrors += verifyDebugInfoForm(Die, AttrValue);
     }
 
+    if (Die.hasChildren()) {
+      if (Die.getFirstChild().isValid() &&
+          Die.getFirstChild().getTag() == DW_TAG_null) {
+        warn() << dwarf::TagString(Die.getTag())
+               << " has DW_CHILDREN_yes but DIE has no children: ";
+        Die.dump(OS);
+      }
+    }
+
     NumUnitErrors += verifyDebugInfoCallSite(Die);
   }
 

llvm/test/DebugInfo/X86/skeleton-unit-verify.s

@@ -3,6 +3,8 @@
 
 # CHECK: Verifying .debug_abbrev...
 # CHECK-NEXT: Verifying .debug_info Unit Header Chain...
+# CHECK-NEXT: warning: DW_TAG_skeleton_unit has DW_CHILDREN_yes but DIE has no children
+# CHECK-NEXT: DW_TAG_skeleton_unit
 # CHECK-NEXT: error: Skeleton compilation unit has children.
 # CHECK-NEXT: Verifying .debug_info references...
 # CHECK-NEXT: Verifying .debug_types Unit Header Chain...
@@ -30,7 +32,7 @@
         .byte   8                       # Address Size (in bytes)
         .long   .debug_abbrev           # Offset Into Abbrev. Section
         .quad   -6573227469967412476
-        .byte   1                       # Abbrev [1] 
+        .byte   1                       # Abbrev [1]
         .byte   0
 .Lcu_end0:
         .long   .Lcu_end1-.Lcu_start1 # Length of Unit

llvm/test/tools/llvm-dwarfdump/X86/verify_die_ranges.s

@@ -3,7 +3,8 @@
 # RUN: | FileCheck %s
 
 # CHECK: Verifying .debug_info Unit Header Chain...
-# CHECK-NEXT: error: Invalid address range [0x0000000000000007, 0x0000000000000006)
+# CHECK: warning: DW_TAG_compile_unit has DW_CHILDREN_yes but DIE has no children:
+# CHECK: error: Invalid address range [0x0000000000000007, 0x0000000000000006)
 
 	.section	__TEXT,__text,regular,pure_instructions
 	.macosx_version_min 10, 12