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[DWARFVerifier] Allow overlapping ranges for ICF-merged functions (ll…
…vm#117952) This patch modifies the DWARF verifier to handle a valid case where two or more functions have identical address ranges due to being merged by ICF (Identical Code Folding). Previously, the verifier would incorrectly report these as errors, but functions merged via ICF (such as when using LLD's --keep-icf-stabs option) can legitimately share the same address range. A new test case has been added to verify this behavior using YAML-based DWARF data that simulates two DW_TAG_subprogram entries with identical address ranges. The test ensures that the verifier correctly identifies this as a valid case and doesn't emit any errors, while still maintaining the existing verification for truly invalid overlapping ranges in other scenarios. Before this change, the newly added test case would have failed, with `llvm-dwarfdump` marking the overlapping address ranges in the DWARF as an error. We also modify the existing tests `llvm-dwarfutil/ELF/X86/verify.test` and `llvm/test/tools/llvm-dwarfdump/X86/verify_parent_zero_length.yaml` which rely on the existence of the error that we're trying to suppress. We slightly change one offset so that the ranges don't perfectly overlap and an error is still generated.
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153 changes: 153 additions & 0 deletions
153
llvm/test/tools/llvm-dwarfdump/X86/verify_no_overlap_error_icf.yaml
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,153 @@ | ||
| #--- comments.txt | ||
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| # 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) | ||
| # This is valid and can happen when ICF (Identical Code Folding) merges functions. | ||
| # 2. Two subprograms can have overlapping ranges when using DW_AT_ranges | ||
| # (shown with func1_with_ranges and func2_with_ranges sharing range 0x5000-0x6000) | ||
| # This is also valid and can occur with -fbasic-block-sections=all | ||
| # 3. The test also verifies that non-identical overlapping ranges are correctly flagged as errors: | ||
| # - When modifying just the first range's high offset from 0x6000 to 0x5999, it creates an invalid subrange overlap | ||
| # - When modifying just the first instance of DW_AT_high_pc 0x77 to 0x66, it creates an invalid function overlap | ||
| # The test ensures llvm-dwarfdump --verify correctly validates these cases by: | ||
| # a) Accepting valid identical overlapping ranges | ||
| # b) Rejecting invalid non-identical overlapping ranges | ||
|
|
||
| # Need to use split-file in order for `sed` calls below to work correctly | ||
| # RUN: split-file %s %t | ||
| # RUN: yaml2obj %t/test.yaml | llvm-dwarfdump --error-display=details --verify - | FileCheck %s | ||
| # CHECK: No errors. | ||
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| # RUN: sed '0,/HighOffset: 0x6000/{s//HighOffset: 0x5999/}' %t/test.yaml | yaml2obj | not llvm-dwarfdump --error-display=details --verify - | FileCheck %s --check-prefix=CHECK-RANGES | ||
| # CHECK-RANGES: error: DIEs have overlapping address ranges | ||
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| # 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 | ||
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| # 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 | ||
|
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| #--- test.yaml | ||
| --- !ELF | ||
| FileHeader: | ||
| Class: ELFCLASS64 | ||
| Data: ELFDATA2LSB | ||
| Type: ET_REL | ||
| Machine: EM_X86_64 | ||
| DWARF: | ||
| debug_abbrev: | ||
| - Table: | ||
| - Tag: DW_TAG_compile_unit | ||
| Children: DW_CHILDREN_yes | ||
| Attributes: | ||
| - Attribute: DW_AT_producer | ||
| Form: DW_FORM_string | ||
| - Attribute: DW_AT_language | ||
| Form: DW_FORM_data2 | ||
| - Attribute: DW_AT_name | ||
| Form: DW_FORM_string | ||
| - Attribute: DW_AT_low_pc | ||
| Form: DW_FORM_addr | ||
| - Attribute: DW_AT_high_pc | ||
| Form: DW_FORM_data8 | ||
| - Tag: DW_TAG_subprogram | ||
| Children: DW_CHILDREN_no | ||
| Attributes: | ||
| - Attribute: DW_AT_name | ||
| Form: DW_FORM_string | ||
| - Attribute: DW_AT_low_pc | ||
| Form: DW_FORM_addr | ||
| - Attribute: DW_AT_high_pc | ||
| Form: DW_FORM_data8 | ||
| - Tag: DW_TAG_subprogram | ||
| Children: DW_CHILDREN_no | ||
| Attributes: | ||
| - Attribute: DW_AT_name | ||
| Form: DW_FORM_string | ||
| - Attribute: DW_AT_ranges | ||
| Form: DW_FORM_sec_offset | ||
| - Tag: DW_TAG_base_type | ||
| Children: DW_CHILDREN_no | ||
| 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 | ||
| Entries: | ||
| - LowOffset: 0x1000 | ||
| HighOffset: 0x2000 | ||
| - LowOffset: 0x3000 | ||
| HighOffset: 0x4000 | ||
| - LowOffset: 0x5000 # Overlaps with 2nd range below | ||
| HighOffset: 0x6000 | ||
| - LowOffset: 0x0 | ||
| HighOffset: 0x0 | ||
| - Offset: 0x50 | ||
| AddrSize: 0x8 | ||
| Entries: | ||
| - LowOffset: 0x2500 | ||
| HighOffset: 0x2800 | ||
| - LowOffset: 0x5000 # Overlaps with 3rd range above | ||
| HighOffset: 0x6000 | ||
| - LowOffset: 0x7000 | ||
| 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: | ||
| - AbbrCode: 1 | ||
| Values: | ||
| - CStr: by_hand | ||
| - Value: 0x04 | ||
| - CStr: CU1 | ||
| - Value: 0x1000 | ||
| - Value: 0x100 | ||
| - AbbrCode: 4 | ||
| Values: | ||
| - CStr: int | ||
| - AbbrCode: 2 | ||
| Values: | ||
| - CStr: foo1 | ||
| - Value: 0x1000 | ||
| - Value: 0x10 | ||
| - AbbrCode: 2 | ||
| Values: | ||
| - CStr: foo2 | ||
| - Value: 0x0 # Overlaps with 'foo3' below | ||
| - Value: 0x77 | ||
| - AbbrCode: 2 | ||
| Values: | ||
| - CStr: foo3 | ||
| - Value: 0x0 # Overlaps with 'foo2' above | ||
| - Value: 0x77 | ||
| - AbbrCode: 3 | ||
| Values: | ||
| - CStr: func1_with_ranges | ||
| - Value: 0x0 | ||
| - AbbrCode: 3 | ||
| 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 | ||
| ... |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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|
@@ -150,7 +150,7 @@ DWARF: | |
| Values: | ||
| - CStr: foo3 | ||
| - Value: 0x0 | ||
| - Value: 0x100 | ||
| - Value: 0x80 | ||
| - Value: 0x00000040 | ||
| - AbbrCode: 0 | ||
| ... | ||