[llvm] [DWARFVerifier] Verify that DW_AT_LLVM_stmt_sequence is set correctly (PR #152807)

[David Blaikie via llvm-commits]

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@@ -0,0 +1,1640 @@
+# Object file copied from llvm/test/tools/dsymutil/ARM/stmt-seq-macho.test
+# Then manually tempered with some of the value of the attribute
+# I hope there are easier ways to construct tests like this.
+
+# RUN: yaml2obj %s -o verify_stmt_seq.o
+# RUN: not llvm-dwarfdump -verify -debug-info verify_stmt_seq.o | FileCheck %s --check-prefix=CHECK_INVALID --implicit-check-not=error:
+# RUN: llvm-dwarfdump -debug-line -verbose -debug-info verify_stmt_seq.o | FileCheck %s --check-prefix=CHECK_DEBUG_LINE
+
+
+# CHECK_INVALID: error: DW_AT_LLVM_stmt_sequence offset 0x00000000 is not within the line table bounds [0x0000002e, 0x000000fd)
+# CHECK_INVALID: DW_AT_LLVM_stmt_sequence [DW_FORM_sec_offset]     (0x00000000)
+
+# 0xd3 would be a valid offset, if the line table wan't ill formed with two rows having the same PC (0x8c).
+# CHECK_INVALID: error: DW_AT_LLVM_stmt_sequence offset 0x000000d3 does not point to a valid sequence offset in the line table
+# CHECK_INVALID: DW_AT_LLVM_stmt_sequence [DW_FORM_sec_offset]     (0x000000d3)
+
+# CHECK_DEBUG_LINE:      0x000000d3: 05 DW_LNS_set_column (85)
+# CHECK_DEBUG_LINE-NEXT: 0x000000d5: 0a DW_LNS_set_prologue_end
+# CHECK_DEBUG_LINE-NEXT: 0x000000d6: 00 DW_LNE_set_address (0x000000000000008c)
+# CHECK_DEBUG_LINE-NEXT: 0x000000e1: 03 DW_LNS_advance_line (30)
+# CHECK_DEBUG_LINE-NEXT: 0x000000e3: 01 DW_LNS_copy
+# CHECK_DEBUG_LINE-NEXT:             0x000000000000008c     30     85      1   0             0       0  is_stmt prologue_end
+# CHECK_DEBUG_LINE-NEXT: 0x000000e4: 00 DW_LNE_end_sequence
+# CHECK_DEBUG_LINE-NEXT:             0x000000000000008c     30     85      1   0             0       0  is_stmt end_sequence
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dwblaikie wrote:

I think potentially both are good/fine - not emitting the stmt_sequence in the first place might be nice but difficult to implement, and (2) might still be useful for older content generated without the fix to (1)

And it'd still be nice to fix the zero-length problem given the issues it creates for DWARF anyway.

And sounds like you also have bugs where a non-zero length function was getting a zero length sequence - which also needs fixing.

But yeah, any/all of these fixes sound good...

https://github.com/llvm/llvm-project/pull/152807