[PATCH] D44205: [ELF] Prevent crash when reporting error messages if debug line cannot be parsed

[James Henderson via Phabricator via llvm-commits]

jhenderson updated this revision to Diff 137379.
jhenderson added a comment.

Return early as suggested.


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D44205

Files:
  ELF/InputFiles.cpp
  test/ELF/Inputs/undef-bad-debug.s
  test/ELF/undef.s


Index: test/ELF/undef.s
===================================================================
--- test/ELF/undef.s
+++ test/ELF/undef.s
@@ -2,9 +2,10 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/undef.s -o %t2.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/undef-debug.s -o %t3.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/undef-bad-debug.s -o %t4.o
 # RUN: llvm-ar rc %t2.a %t2.o
-# RUN: not ld.lld %t.o %t2.a %t3.o -o %t.exe 2>&1 | FileCheck %s
-# RUN: not ld.lld -pie %t.o %t2.a %t3.o -o %t.exe 2>&1 | FileCheck %s
+# RUN: not ld.lld %t.o %t2.a %t3.o %t4.o -o %t.exe 2>&1 | FileCheck %s
+# RUN: not ld.lld -pie %t.o %t2.a %t3.o %t4.o -o %t.exe 2>&1 | FileCheck %s
 
 # CHECK: error: undefined symbol: foo
 # CHECK: >>> referenced by undef.s
@@ -33,6 +34,9 @@
 # CHECK: >>> referenced by undef-debug.s:11 (dir{{/|\\}}undef-debug.s:11)
 # CHECK: >>>               {{.*}}.o:(.text.2+0x0)
 
+# CHECK: error: undefined symbol: zed6
+# CHECK: >>> referenced by {{.*}}tmp4.o:(.text+0x0)
+
 # RUN: not ld.lld %t.o %t2.a -o %t.exe -no-demangle 2>&1 | \
 # RUN:   FileCheck -check-prefix=NO-DEMANGLE %s
 # NO-DEMANGLE: error: undefined symbol: _Z3fooi
Index: test/ELF/Inputs/undef-bad-debug.s
===================================================================
--- test/ELF/Inputs/undef-bad-debug.s
+++ test/ELF/Inputs/undef-bad-debug.s
@@ -0,0 +1,44 @@
+.section .text,"ax"
+sym:
+    .quad zed6
+    
+.section .debug_info,"", at progbits
+    .long   .Lcu_end - .Lcu_start   # Length of Unit
+.Lcu_start:
+    .short  4                       # DWARF version number
+    .long   .Lsection_abbrev        # Offset Into Abbrev. Section
+    .byte   8                       # Address Size (in bytes)
+    .byte   1                       # Abbrev [1] 0xb:0x79 DW_TAG_compile_unit
+    .byte   2                       # Abbrev [2] 0x2a:0x15 DW_TAG_variable
+    .long   .Linfo_string           # DW_AT_name
+                                        # DW_AT_external
+    .byte   1                       # DW_AT_decl_file
+    .byte   3                       # DW_AT_decl_line
+    .byte   0                       # End Of Children Mark
+.Lcu_end:
+
+.section .debug_abbrev,"", at progbits
+.Lsection_abbrev:
+    .byte   1                       # Abbreviation Code
+    .byte   17                      # DW_TAG_compile_unit
+    .byte   1                       # DW_CHILDREN_yes
+    .byte   0                       # EOM(1)
+    .byte   0                       # EOM(2)
+    .byte   2                       # Abbreviation Code
+    .byte   52                      # DW_TAG_variable
+    .byte   0                       # DW_CHILDREN_no
+    .byte   3                       # DW_AT_name
+    .byte   14                      # DW_FORM_strp
+    .byte   63                      # DW_AT_external
+    .byte   25                      # DW_FORM_flag_present
+    .byte   58                      # DW_AT_decl_file
+    .byte   11                      # DW_FORM_data1
+    .byte   59                      # DW_AT_decl_line
+    .byte   11                      # DW_FORM_data1
+    .byte   0                       # EOM(1)
+    .byte   0                       # EOM(2)
+    .byte   0                       # EOM(3)
+
+.section .debug_str,"MS", at progbits,1
+.Linfo_string:
+    .asciz "sym"
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -126,6 +126,8 @@
   // CU (object file), so offset is always 0.
   const DWARFDebugLine::LineTable *LT =
       DwarfLine->getOrParseLineTable(LineData, 0, Dwarf, nullptr);
+  if (!LT)
+    return;
 
   // Return if there is no debug information about CU available.
   if (!Dwarf.getNumCompileUnits())


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