[test][llvm-dwarfdump] Add extra test case for invalid MD5 form

[jhenderson]

Summary

A subsequent patch will change how an invalid file name table is handled to allow parsing to continue. This patch adds a test case that will demonstrate a difference in behaviour with that change between invalid file tables where the error is before the end of the stated prologue length and where the error occurs after the stated length.

[jhenderson]

Early ping - I'd like to get this and the other related reviews in before the release branch is created if possible.

[dblaikie]

I guess these error messages could be more precise about what's invalid & why it's invalid. In this case I guess it's invalid because the DW_LNCT_MD5 has a form that contains only one byte, not large enough to encode a whole MD5 sum?

& this is to demonstrate that other things can still be parsed in spite of that failure?

[jhenderson]

In D72157#1813368, @dblaikie wrote:

I guess these error messages could be more precise about what's invalid & why it's invalid. In this case I guess it's invalid because the DW_LNCT_MD5 has a form that contains only one byte, not large enough to encode a whole MD5 sum?

I agree with making the error message more precise, but that's probably a different change. It's invalid as you say due to the bad form (I think that's the only way it can be invalid).

& this is to demonstrate that other things can still be parsed in spite of that failure?

Right. It goes with the follow-on change D72158 that shows that parsing will continue after the failure. Following that change, there'll be two different cases to handle, which result in different sets of warnings. Note that in D72158 one of the two MD5 invalid hashes results in a "size doesn't match" warning, in addition to the current ones and the other doesn't. We need to have the different cases to show that the offset is updated appropriately after the failure.

[jhenderson]

Rebase.

[jhenderson]

Ping?

[dblaikie]

Looks good - James, I might've asked this on another thread - but could you write up a brief goals/design email of what your overall goal is with these patches? There seem to be enough of them that it'd be helpful to link to in each review (and summarize where the patch fits in the broader scheme of things) & provide framing when reviewing patches to better understand the overall goals.

[jhenderson]

In D72157#1827583, @dblaikie wrote:

Looks good - James, I might've asked this on another thread - but could you write up a brief goals/design email of what your overall goal is with these patches? There seem to be enough of them that it'd be helpful to link to in each review (and summarize where the patch fits in the broader scheme of things) & provide framing when reviewing patches to better understand the overall goals.

Thanks. As you probably saw, I did previously write up comments in D72155. I'll post something on the mailing list at some point in the next couple of days, in order to clarify everything.

llvm/test/tools/llvm-dwarfdump/X86/Inputs/debug_line_malformed.s

 .asciz  "a.c"
 .byte   1
 .Linvalid_dir_header_end0:
 .byte   0, 9, 2         # DW_LNE_set_address
 .quad   0x4444333322221111
 .byte   0, 1, 1         # DW_LNE_end_sequence
 .Linvalid_dir_end0:
 
-# Invalid MD5 hash.
+# Invalid MD5 hash, where there is data still to be read afterwards.
 .long   .Linvalid_md5_end0-.Linvalid_md5_start0   # Length of Unit
 .Linvalid_md5_start0:
 .short  5               # DWARF version number
 .byte   8               # Address Size
 .byte   0               # Segment Selector Size
 .long   .Linvalid_md5_header_end0-.Linvalid_md5_params0     # Length of Prologue
 .Linvalid_md5_params0:
 .byte   1               # Minimum Instruction Length

 .byte   0x08            # DW_FORM_string
 # Directory table entries
 .byte   1               # 1 directory
 .asciz  "/tmp"
 # File table format
 .byte   3               # 3 elements per file entry
 .byte   1               # DW_LNCT_path
 .byte   0x08            # DW_FORM_string
+.byte   5               # DW_LNCT_MD5
+.byte   0x0b            # DW_FORM_data1
 .byte   2               # DW_LNCT_directory_index
 .byte   0x0b            # DW_FORM_data1
-.byte   5               # DW_LNCT_MD5
-.byte   0x09            # DW_FORM_data1
 # File table entries
 .byte   1               # 1 file
 .asciz  "a.c"
 .byte   0
+# Data to show that the rest of the prologue is skipped.
+.byte   6
 .Linvalid_md5_header_end0:
 .byte   0, 9, 2         # DW_LNE_set_address
 .quad   0x1234123412341234
 .byte   0, 1, 1         # DW_LNE_end_sequence
 .Linvalid_md5_end0:
 
+# Invalid MD5 hash, when data beyond the prologue length has
+# been read before the MD5 problem is identified.
+.long   .Linvalid_md5_end1-.Linvalid_md5_start1   # Length of Unit
+.Linvalid_md5_start1:
+.short  5               # DWARF version number
+.byte   8               # Address Size
+.byte   0               # Segment Selector Size
+.long   .Linvalid_md5_header_end1-.Linvalid_md5_params1 - 10 # Length of Prologue
+.Linvalid_md5_params1:
+.byte   1               # Minimum Instruction Length
+.byte   1               # Maximum Operations per Instruction
+.byte   1               # Default is_stmt
+.byte   -5              # Line Base
+.byte   14              # Line Range
+.byte   13              # Opcode Base
+.byte   0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 # Standard Opcode Lengths
+# Directory table format
+.byte   1               # One element per directory entry
+.byte   1               # DW_LNCT_path
+.byte   0x08            # DW_FORM_string
+# Directory table entries
+.byte   1               # 1 directory
+.asciz  "/tmp"
+# File table format
+.byte   3               # 2 elements per file entry
+.byte   1               # DW_LNCT_path
+.byte   0x08            # DW_FORM_string
+.byte   5               # DW_LNCT_MD5
+.byte   0x0b            # DW_FORM_data1
+.byte   2               # DW_LNCT_directory_index
+.byte   0x0b            # DW_FORM_data1
+# File table entries
+.byte   1               # 1 file
+.asciz  "a.c"
+.byte   6               # This byte will be consumed when reading the MD5 value.
+.byte   0xb             # This byte will not be read as part of the prologue.
+.Linvalid_md5_header_end1:
+.byte   0, 9, 2         # DW_LNE_set_address
+.quad   0x4321432143214321
+.byte   0, 1, 1         # DW_LNE_end_sequence
+.Linvalid_md5_end1:
+
 # Trailing good section.
 .long   .Lunit_good_end - .Lunit_good_start # Length of Unit (DWARF-32 format)
 .Lunit_good_start:
 .short  4               # DWARF version number
 .long   .Lprologue_good_end-.Lprologue_good_start # Length of Prologue
 .Lprologue_good_start:
 .byte   1               # Minimum Instruction Length
 .byte   1               # Maximum Operations per Instruction

llvm/test/tools/llvm-dwarfdump/X86/debug_line_invalid.test

 # RUN: FileCheck %s --input-file=%t-malformed-verbose.err --check-prefixes=ALL,OTHER
 
 ## We should still produce warnings for malformed tables after the specified unit.
 # RUN: llvm-dwarfdump -debug-line=0 %t-malformed.o 2> %t-malformed-off-first.err \
 # RUN:   | FileCheck %s --check-prefixes=FIRST,NOLATER
 # RUN: FileCheck %s --input-file=%t-malformed-off-first.err --check-prefix=ALL
 
 ## Don't stop looking for the later unit if non-fatal issues are found.
-# RUN: llvm-dwarfdump -debug-line=0x2b4 %t-malformed.o 2> %t-malformed-off-last.err \
+# RUN: llvm-dwarfdump -debug-line=0x2f8 %t-malformed.o 2> %t-malformed-off-last.err \
 # RUN:   | FileCheck %s --check-prefix=LAST --implicit-check-not='debug_line[{{.*}}]'
 # RUN: FileCheck %s --input-file=%t-malformed-off-last.err --check-prefix=ALL
 
 # FIRST:       debug_line[0x00000000]
 # FIRST:       0x000000000badbeef {{.*}} end_sequence
 # NOFIRST-NOT: debug_line[0x00000000]
 # NOFIRST-NOT: 0x000000000badbeef {{.*}} end_sequence
 # NOLATER-NOT: debug_line[{{.*}}]

 # NONFATAL:      debug_line[0x00000232]
 # NONFATAL-NEXT: Line table prologue
 # NONFATAL:      include_directories[  0] = "/tmp"
 # NONFATAL-NEXT: file_names[  0]:
 # NONFATAL-NEXT:            name: "a.c"
 # NONFATAL-NEXT:       dir_index: 1
 # NONFATAL-NOT:  Address
 
-## Case 11: V5 invalid MD5 hash form.
+## Case 11: V5 invalid MD5 hash form when there is still data to be read.
 # NONFATAL:      debug_line[0x00000272]
 # NONFATAL-NEXT: Line table prologue
 # NONFATAL:      include_directories[  0] = "/tmp"
 # NONFATAL-NOT:  file_names
 # NONFATAL-NOT:  Address
 
-# LAST:          debug_line[0x000002b4]
+## Case 12: V5 invalid MD5 hash form when data beyond the prologue length has
+## been read before the MD5 problem is identified.
+# NONFATAL: debug_line[0x000002b5]
+# NONFATAL-NEXT: Line table prologue
+# NONFATAL:      include_directories[  0] = "/tmp"
+# NONFATAL-NOT:  file_names
+# NONFATAL-NOT:  Address
+
+# LAST:          debug_line[0x000002f8]
 # LAST:          0x00000000cafebabe {{.*}} end_sequence
 
 # RESERVED: warning: parsing line table prologue at offset 0x00000048 unsupported reserved unit length found of value 0xfffffffe
 
 # ALL-NOT:  warning:
 # ALL:      warning: parsing line table prologue at offset 0x00000048 found unsupported version 0x00
 # ALL-NEXT: warning: parsing line table prologue at offset 0x0000004e found unsupported version 0x01
 # ALL-NEXT: warning: parsing line table prologue at 0x00000054 found an invalid directory or file table description at 0x00000073
 # ALL-NEXT: warning: failed to parse entry content descriptions because no path was found
 # FIXME - The latter offset in the next line should be 0xad. The filename parsing code does not notice a missing terminating byte.
 # ALL-NEXT: warning: parsing line table prologue at 0x00000081 should have ended at 0x000000b9 but it ended at 0x000000ba
 # ALL-NEXT: warning: parsing line table prologue at 0x000000c9 should have ended at 0x00000104 but it ended at 0x00000103
 # OTHER-NEXT: warning: unexpected line op length at offset 0x00000158 expected 0x02 found 0x01
 # OTHER-NEXT: warning: unexpected line op length at offset 0x0000015c expected 0x01 found 0x02
 # OTHER-NEXT: warning: last sequence in debug line table at offset 0x0000016c is not terminated
 # ALL-NEXT: warning: parsing line table prologue at 0x000001b2 should have ended at 0x000001cd but it ended at 0x000001e4
 # ALL-NEXT: warning: parsing line table prologue at 0x000001f2 should have ended at 0x0000021d but it ended at 0x00000224
 # ALL-NEXT: warning: parsing line table prologue at 0x00000232 should have ended at 0x00000254 but it ended at 0x00000264
-# ALL-NEXT: warning: parsing line table prologue at 0x00000272 found an invalid directory or file table description at 0x000002a7
+# ALL-NEXT: warning: parsing line table prologue at 0x00000272 found an invalid directory or file table description at 0x000002a6
+# ALL-NEXT: warning: failed to parse file entry because the MD5 hash is invalid
+# ALL-NEXT: warning: parsing line table prologue at 0x000002b5 found an invalid directory or file table description at 0x000002e9
 # ALL-NEXT: warning: failed to parse file entry because the MD5 hash is invalid
 # ALL-NOT:  warning: