[DWARFVerifier] Allow overlapping ranges for ICF-merged functions

llvm/include/llvm/DebugInfo/DWARF/DWARFVerifier.h

@@ -73,7 +73,8 @@ class DWARFVerifier {
     /// This is used for finding overlapping ranges in the DW_AT_ranges
     /// attribute of a DIE. It is also used as a set of address ranges that
     /// children address ranges must all be contained in.
-    std::optional<DWARFAddressRange> insert(const DWARFAddressRange &R);
+    std::optional<DWARFAddressRange> insert(const DWARFAddressRange &R,
+                                            bool AllowDuplicates = false);
 
     /// Inserts the address range info. If any of its ranges overlaps with a
     /// range in an existing range info, the range info is *not* added and an

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

@@ -48,11 +48,17 @@ class DWARFDebugInfoEntry;
 }
 
 std::optional<DWARFAddressRange>
-DWARFVerifier::DieRangeInfo::insert(const DWARFAddressRange &R) {
+DWARFVerifier::DieRangeInfo::insert(const DWARFAddressRange &R,
+                                    bool AllowDuplicates) {
   auto Begin = Ranges.begin();
   auto End = Ranges.end();
   auto Pos = std::lower_bound(Begin, End, R);
 
+  // Check for exact duplicates if duplicates are not allowed
+  if (AllowDuplicates && Pos != End && *Pos == R) {
+    return std::nullopt;
+  }
+
   if (Pos != End) {
     DWARFAddressRange Range(*Pos);
     if (Pos->merge(R))
@@ -613,7 +619,7 @@ unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die,
       // to have. Compile units often have DW_AT_ranges that can contain one or
       // more dead stripped address ranges which tend to all be at the same
       // address: 0 or -1.
-      if (auto PrevRange = RI.insert(Range)) {
+      if (auto PrevRange = RI.insert(Range, /*AllowDuplicates = */ true)) {
         ++NumErrors;
         ErrorCategory.Report("DIE has overlapping DW_AT_ranges", [&]() {
           error() << "DIE has overlapping ranges in DW_AT_ranges attribute: "
@@ -627,8 +633,8 @@ unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die,
   }
 
   // Verify that children don't intersect.
-  bool AllowDuplicates = Die.getTag() == DW_TAG_subprogram;
-  const auto IntersectingChild = ParentRI.insert(RI, AllowDuplicates);
+  const auto IntersectingChild =
+      ParentRI.insert(RI, /*AllowDuplicates = */ true);
   if (IntersectingChild != ParentRI.Children.end()) {
     ++NumErrors;
     ErrorCategory.Report("DIEs have overlapping address ranges", [&]() {

llvm/test/tools/llvm-dwarfdump/X86/verify_no_overlap_error_icf.yaml

@@ -1,4 +1,4 @@
-//--- comments.txt
+#--- comments.txt
 
 # This test verifies several scenarios with DW_TAG_subprogram address ranges:
 # 1. Two subprograms can have identical ranges (shown with foo2 and foo3 having same low_pc/high_pc)
@@ -24,7 +24,10 @@
 # RUN: sed '0,/Value:  0x77/{s/Value:  0x77/Value:  0x66/}' %t/test.yaml | yaml2obj | not llvm-dwarfdump --error-display=details --verify - | FileCheck %s --check-prefix=CHECK-HIGH-PC
 # CHECK-HIGH-PC: error: DIEs have overlapping address ranges
 
-//--- test.yaml
+# RUN: sed '0,/LowOffset:  0x880111/{s//LowOffset:  0x880112/}' %t/test.yaml | yaml2obj | not llvm-dwarfdump --error-display=details --verify - | FileCheck %s --check-prefix=CHECK-LEX-BLOCK
+# CHECK-LEX-BLOCK: DIE has overlapping ranges in DW_AT_ranges attribute
+
+#--- test.yaml
 --- !ELF
 FileHeader:
   Class:    ELFCLASS64
@@ -68,6 +71,11 @@ DWARF:
         Attributes:
           - Attribute: DW_AT_name
             Form:      DW_FORM_string
+      - Tag:      DW_TAG_lexical_block
+        Children: DW_CHILDREN_no
+        Attributes:
+          - Attribute: DW_AT_ranges
+            Form:      DW_FORM_sec_offset
   debug_ranges:
     - Offset:    0x0
       AddrSize:  0x8
@@ -91,6 +99,17 @@ DWARF:
           HighOffset: 0x8000
         - LowOffset:  0x0
           HighOffset: 0x0
+    - Offset: 0xA0   # Added Range List #3 for lexical block
+      AddrSize: 0x8
+      Entries:
+        - LowOffset:  0x880111
+          HighOffset: 0x881222
+        - LowOffset:  0x882333
+          HighOffset: 0x883444
+        - LowOffset:  0x880111  # Overlaps with 1st range in the same list
+          HighOffset: 0x881222
+        - LowOffset:  0x0   # End of list
+          HighOffset: 0x0
   debug_info:
     - Version: 4
       Entries:
@@ -127,5 +146,8 @@ DWARF:
           Values:
             - CStr: func2_with_ranges
             - Value:  0x50
+        - AbbrCode: 5   # Added lexical block using ranges
+          Values:
+            - Value: 0xA0 # Range list index in debug_ranges
         - AbbrCode: 0
 ...