[llvm] Skip over empty line table entries.

Summary:
This is similar to how addr2line handles consecutive entries with the
same address - pick the last one.

Reviewers: dblaikie, friss, JDevlieghere

Reviewed By: dblaikie

Subscribers: ormris, echristo, JDevlieghere, probinson, aprantl, hiraditya, rupprecht, jdoerfert, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D58952

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355972 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index a2c25248618427031dc762a3d11a325c395ed9db..dee9428be29fb2ae16d11157f6f59f321f58a42e 100644 (file)
--- a/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -872,6 +872,13 @@ uint32_t DWARFDebugLine::LineTable::findRowInSeq(
   if (RowPos == LastRow) {
     return Seq.LastRowIndex - 1;
   }
+  // In some cases, e.g. first instruction in a function, the compiler generates
+  // two entries, both with the same address. We want the last one.
+  while (RowPos + 1 < LastRow &&
+         RowPos->Address.Address == (RowPos + 1)->Address.Address) {
+    ++RowPos;
+  }
+  assert(RowPos < LastRow);
   assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
   uint32_t Index = Seq.FirstRowIndex + (RowPos - FirstRow);
   if (RowPos->Address.Address > Address.Address) {

diff --git a/test/tools/llvm-symbolizer/fission-ranges.test b/test/tools/llvm-symbolizer/fission-ranges.test
index 4d35ed4f29383a437c6e673899ff466a724fda65..6f3cb24fcdaa95e9f691e67184eb5d5ad900a8a0 100644 (file)
--- a/test/tools/llvm-symbolizer/fission-ranges.test
+++ b/test/tools/llvm-symbolizer/fission-ranges.test
@@ -1,4 +1,4 @@
 RUN: llvm-symbolizer --obj=%p/Inputs/fission-ranges.elf-x86_64 0x720 | FileCheck %s
 
 CHECK: main
-CHECK-NEXT: {{.*}}fission-ranges.cc:6
+CHECK-NEXT: {{.*}}fission-ranges.cc:2

diff --git a/test/tools/llvm-symbolizer/only-empty-ranges.s b/test/tools/llvm-symbolizer/only-empty-ranges.s
new file mode 100644 (file)
index 0000000..16dbc95
--- /dev/null
+++ b/test/tools/llvm-symbolizer/only-empty-ranges.s
@@ -0,0 +1,213 @@
+# REQUIRES: x86-registered-target
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: llvm-symbolizer 0x0 0x3 0x4 --obj=%t.o | FileCheck %s
+# This test makes sure we don't attempt to access out of the line table boundaries
+# if the last range is empty.
+# Produced from the following program:
+# int func(int a) {
+#   return 1 + a;
+# }
+# compiled with clang -O3 -g -S
+# Edited by adding a redundant, empty last range.
+# The line table (llvm-dwarfdump --debug-line) looks like:
+#
+# Address            Line   Column File   ISA Discriminator Flags
+# ------------------ ------ ------ ------ --- ------------- -------------
+# 0x0000000000000000      1      0      1   0             0  is_stmt
+# 0x0000000000000000      2     12      1   0             0  is_stmt prologue_end
+# 0x0000000000000003      2      3      1   0             0
+# 0x0000000000000003      3      3      1   0             0
+# 0x0000000000000004      3      3      1   0             0  end_sequence
+#
+# CHECK:    func
+# CHECK:       /scratch/a.cpp:2:12
+# CHECK:    func
+# CHECK:       /scratch/a.cpp:3:3
+# CHECK: ??
+# CHECK: ??:0:0
+
+       .text
+       .file   "a.cpp"
+       .globl  _Z4funci                # -- Begin function _Z4funci
+       .p2align        4, 0x90
+       .type   _Z4funci,@function
+_Z4funci:                               # @_Z4funci
+.Lfunc_begin0:
+       .file   1 "/llvm-project" "/scratch/a.cpp"
+       .loc    1 1 0                   # /scratch/a.cpp:1:0
+       .cfi_startproc
+# %bb.0:
+       #DEBUG_VALUE: func:a <- $edi
+                                        # kill: def $edi killed $edi def $rdi
+       #DEBUG_VALUE: func:a <- $edi
+       .loc    1 2 12 prologue_end     # /scratch/a.cpp:2:12
+       leal    1(%rdi), %eax
+       .loc    1 2 3                   # /scratch/a.cpp:2:3
+    .loc    1 3 3 is_stmt 0         # this forms an empty range torgether with the previous.
+       retq
+.Ltmp0:
+.Lfunc_end0:
+       .size   _Z4funci, .Lfunc_end0-_Z4funci
+       .cfi_endproc
+                                        # -- End function
+       .section        .debug_str,"MS",@progbits,1
+.Linfo_string0:
+       .asciz  "clang version 7.0.1-6 (tags/RELEASE_701/final)" # string offset=0
+.Linfo_string1:
+       .asciz  "/scratch/a.cpp" # string offset=47
+.Linfo_string2:
+       .asciz  "/llvm-project" # string offset=97
+.Linfo_string3:
+       .asciz  "_Z4funci"              # string offset=146
+.Linfo_string4:
+       .asciz  "func"                  # string offset=155
+.Linfo_string5:
+       .asciz  "int"                   # string offset=160
+.Linfo_string6:
+       .asciz  "a"                     # string offset=164
+       .section        .debug_loc,"",@progbits
+.Ldebug_loc0:
+       .quad   .Lfunc_begin0-.Lfunc_begin0
+       .quad   .Lfunc_end0-.Lfunc_begin0
+       .short  1                       # Loc expr size
+       .byte   85                      # super-register DW_OP_reg5
+       .quad   0
+       .quad   0
+       .section        .debug_abbrev,"",@progbits
+       .byte   1                       # Abbreviation Code
+       .byte   17                      # DW_TAG_compile_unit
+       .byte   1                       # DW_CHILDREN_yes
+       .byte   37                      # DW_AT_producer
+       .byte   14                      # DW_FORM_strp
+       .byte   19                      # DW_AT_language
+       .byte   5                       # DW_FORM_data2
+       .byte   3                       # DW_AT_name
+       .byte   14                      # DW_FORM_strp
+       .byte   16                      # DW_AT_stmt_list
+       .byte   23                      # DW_FORM_sec_offset
+       .byte   27                      # DW_AT_comp_dir
+       .byte   14                      # DW_FORM_strp
+       .ascii  "\264B"                 # DW_AT_GNU_pubnames
+       .byte   25                      # DW_FORM_flag_present
+       .byte   17                      # DW_AT_low_pc
+       .byte   1                       # DW_FORM_addr
+       .byte   18                      # DW_AT_high_pc
+       .byte   6                       # DW_FORM_data4
+       .byte   0                       # EOM(1)
+       .byte   0                       # EOM(2)
+       .byte   2                       # Abbreviation Code
+       .byte   46                      # DW_TAG_subprogram
+       .byte   1                       # DW_CHILDREN_yes
+       .byte   17                      # DW_AT_low_pc
+       .byte   1                       # DW_FORM_addr
+       .byte   18                      # DW_AT_high_pc
+       .byte   6                       # DW_FORM_data4
+       .byte   64                      # DW_AT_frame_base
+       .byte   24                      # DW_FORM_exprloc
+       .byte   110                     # DW_AT_linkage_name
+       .byte   14                      # DW_FORM_strp
+       .byte   3                       # DW_AT_name
+       .byte   14                      # DW_FORM_strp
+       .byte   58                      # DW_AT_decl_file
+       .byte   11                      # DW_FORM_data1
+       .byte   59                      # DW_AT_decl_line
+       .byte   11                      # DW_FORM_data1
+       .byte   73                      # DW_AT_type
+       .byte   19                      # DW_FORM_ref4
+       .byte   63                      # DW_AT_external
+       .byte   25                      # DW_FORM_flag_present
+       .byte   0                       # EOM(1)
+       .byte   0                       # EOM(2)
+       .byte   3                       # Abbreviation Code
+       .byte   5                       # DW_TAG_formal_parameter
+       .byte   0                       # DW_CHILDREN_no
+       .byte   2                       # DW_AT_location
+       .byte   23                      # DW_FORM_sec_offset
+       .byte   3                       # DW_AT_name
+       .byte   14                      # DW_FORM_strp
+       .byte   58                      # DW_AT_decl_file
+       .byte   11                      # DW_FORM_data1
+       .byte   59                      # DW_AT_decl_line
+       .byte   11                      # DW_FORM_data1
+       .byte   73                      # DW_AT_type
+       .byte   19                      # DW_FORM_ref4
+       .byte   0                       # EOM(1)
+       .byte   0                       # EOM(2)
+       .byte   4                       # Abbreviation Code
+       .byte   36                      # DW_TAG_base_type
+       .byte   0                       # DW_CHILDREN_no
+       .byte   3                       # DW_AT_name
+       .byte   14                      # DW_FORM_strp
+       .byte   62                      # DW_AT_encoding
+       .byte   11                      # DW_FORM_data1
+       .byte   11                      # DW_AT_byte_size
+       .byte   11                      # DW_FORM_data1
+       .byte   0                       # EOM(1)
+       .byte   0                       # EOM(2)
+       .byte   0                       # EOM(3)
+       .section        .debug_info,"",@progbits
+.Lcu_begin0:
+       .long   91                      # Length of Unit
+       .short  4                       # DWARF version number
+       .long   .debug_abbrev           # Offset Into Abbrev. Section
+       .byte   8                       # Address Size (in bytes)
+       .byte   1                       # Abbrev [1] 0xb:0x54 DW_TAG_compile_unit
+       .long   .Linfo_string0          # DW_AT_producer
+       .short  4                       # DW_AT_language
+       .long   .Linfo_string1          # DW_AT_name
+       .long   .Lline_table_start0     # DW_AT_stmt_list
+       .long   .Linfo_string2          # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+       .quad   .Lfunc_begin0           # DW_AT_low_pc
+       .long   .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+       .byte   2                       # Abbrev [2] 0x2a:0x2d DW_TAG_subprogram
+       .quad   .Lfunc_begin0           # DW_AT_low_pc
+       .long   .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+       .byte   1                       # DW_AT_frame_base
+       .byte   87
+       .long   .Linfo_string3          # DW_AT_linkage_name
+       .long   .Linfo_string4          # DW_AT_name
+       .byte   1                       # DW_AT_decl_file
+       .byte   1                       # DW_AT_decl_line
+       .long   87                      # DW_AT_type
+                                        # DW_AT_external
+       .byte   3                       # Abbrev [3] 0x47:0xf DW_TAG_formal_parameter
+       .long   .Ldebug_loc0            # DW_AT_location
+       .long   .Linfo_string6          # DW_AT_name
+       .byte   1                       # DW_AT_decl_file
+       .byte   1                       # DW_AT_decl_line
+       .long   87                      # DW_AT_type
+       .byte   0                       # End Of Children Mark
+       .byte   4                       # Abbrev [4] 0x57:0x7 DW_TAG_base_type
+       .long   .Linfo_string5          # DW_AT_name
+       .byte   5                       # DW_AT_encoding
+       .byte   4                       # DW_AT_byte_size
+       .byte   0                       # End Of Children Mark
+       .section        .debug_macinfo,"",@progbits
+       .byte   0                       # End Of Macro List Mark
+       .section        .debug_pubnames,"",@progbits
+       .long   .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+       .short  2                       # DWARF Version
+       .long   .Lcu_begin0             # Offset of Compilation Unit Info
+       .long   95                      # Compilation Unit Length
+       .long   42                      # DIE offset
+       .asciz  "func"                  # External Name
+       .long   0                       # End Mark
+.LpubNames_end0:
+       .section        .debug_pubtypes,"",@progbits
+       .long   .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+       .short  2                       # DWARF Version
+       .long   .Lcu_begin0             # Offset of Compilation Unit Info
+       .long   95                      # Compilation Unit Length
+       .long   87                      # DIE offset
+       .asciz  "int"                   # External Name
+       .long   0                       # End Mark
+.LpubTypes_end0:
+
+       .ident  "clang version 7.0.1-6 (tags/RELEASE_701/final)"
+       .section        ".note.GNU-stack","",@progbits
+       .addrsig
+       .section        .debug_line,"",@progbits
+.Lline_table_start0:

diff --git a/test/tools/llvm-symbolizer/sym-verbose.test b/test/tools/llvm-symbolizer/sym-verbose.test
index 5b401e3b0982f530ec48318fcffa2d2029e949a2..c12eb3b530e1bdeb6cecceb327c0565b902a8b06 100644 (file)
--- a/test/tools/llvm-symbolizer/sym-verbose.test
+++ b/test/tools/llvm-symbolizer/sym-verbose.test
@@ -19,8 +19,8 @@ RUN: llvm-symbolizer -verbose -print-address -obj=%p/Inputs/discrim < %p/Inputs/
 #CHECK-NEXT: foo
 #CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 #CHECK-NEXT: Function start line: 4
-#CHECK-NEXT: Line: 9
-#CHECK-NEXT: Column: 0
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 7
 #CHECK-NEXT: main
 #CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 #CHECK-NEXT: Function start line: 9