[ELF] Rework debug line parsing to use llvm::Error and callbacks (LLD-side)

Reviewed by: ruiu, grimar, espindola

Differential Revision: https://reviews.llvm.org/D44562

Summary:
r331971 changes the debug line parser interface to report LLVM errors in an
interface that different executables can use, rather than always being printed
directly as warnings to stderr. This change allows LLD to make use of the new
interface and call its own warning methods to report problems.

llvm-svn: 331972

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 5f9b1f4..3bf844d 100644 (file)
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -131,7 +131,14 @@ template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
                               Config->Wordsize);
 
   for (std::unique_ptr<DWARFCompileUnit> &CU : Dwarf->compile_units()) {
-    const DWARFDebugLine::LineTable *LT = Dwarf->getLineTableForUnit(CU.get());
+    Expected<const DWARFDebugLine::LineTable *> ExpectedLT =
+        Dwarf->getLineTableForUnit(CU.get(), warn);
+    const DWARFDebugLine::LineTable *LT = nullptr;
+    if (ExpectedLT)
+      LT = *ExpectedLT;
+    else
+      handleAllErrors(ExpectedLT.takeError(),
+                      [](ErrorInfoBase &Err) { warn(Err.message()); });
     if (!LT)
       continue;
     LineTables.push_back(LT);

diff --git a/lld/test/ELF/Inputs/undef-bad-debug.s b/lld/test/ELF/Inputs/undef-bad-debug.s
index c887b28..e3e9f5e 100644 (file)
--- a/lld/test/ELF/Inputs/undef-bad-debug.s
+++ b/lld/test/ELF/Inputs/undef-bad-debug.s
@@ -1,7 +1,77 @@
 .section .text,"ax"
 sym:
     .quad zed6
-    
+sym2:
+    .quad zed7
+
+.section .debug_line,"",@progbits
+.Lunit:
+    .long .Lunit_end - .Lunit_start # unit length
+.Lunit_start:
+    .short 4                        # version
+    .long .Lprologue_end - .Lprologue_start # prologue length
+.Lprologue_start:
+    .byte 1                         # minimum instruction length
+    .byte 1                         # maximum operatiosn 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
+    .asciz "dir"                    # include directories
+    .byte 0
+    .asciz "undef-bad-debug.s"      # file names
+    .byte 1, 0, 0
+    .byte 0
+    .byte 0                         # extraneous byte
+.Lprologue_end:
+    .byte 0, 9, 2                   # DW_LNE_set_address
+    .quad sym
+    .byte 3                         # DW_LNS_advance_line
+    .byte 10
+    .byte 1                         # DW_LNS_copy
+    .byte 2                         # DW_LNS_advance_pc
+    .byte 8
+    .byte 0, 1, 1                   # DW_LNE_end_sequence
+.Lunit_end:
+
+.Lunit2:
+    .long .Lunit2_end - .Lunit2_start # unit length
+.Lunit2_start:
+    .short 4                        # version
+    .long .Lprologue2_end - .Lprologue2_start # prologue length
+.Lprologue2_start:
+    .byte 1                         # minimum instruction length
+    .byte 1                         # maximum operatiosn 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
+    .asciz "dir2"                   # include directories
+    .byte 0
+    .asciz "undef-bad-debug2.s"     # file names
+    .byte 1, 0, 0
+    .byte 0
+.Lprologue2_end:
+    .byte 0, 9, 2                   # DW_LNE_set_address
+    .quad sym2
+    .byte 3                         # DW_LNS_advance_line
+    .byte 10
+    .byte 1                         # DW_LNS_copy
+    .byte 2                         # DW_LNS_advance_pc
+    .byte 8
+    .byte 0, 1, 1                   # DW_LNE_end_sequence
+    .byte 0, 9, 2                   # DW_LNE_set_address
+    .quad 0x0badbeef
+    .byte 3                         # DW_LNS_advance_line
+    .byte 99
+    .byte 1                         # DW_LNS_copy
+    .byte 99                        # DW_LNS_advance_pc
+    .byte 119
+    # Missing end of sequence.
+.Lunit2_end:
+
 .section .debug_info,"",@progbits
     .long   .Lcu_end - .Lcu_start   # Length of Unit
 .Lcu_start:
@@ -9,6 +79,7 @@ sym:
     .long   .Lsection_abbrev        # Offset Into Abbrev. Section
     .byte   8                       # Address Size (in bytes)
     .byte   1                       # Abbrev [1] 0xb:0x79 DW_TAG_compile_unit
+    .long   .Lunit                  # DW_AT_stmt_list
     .byte   2                       # Abbrev [2] 0x2a:0x15 DW_TAG_variable
     .long   .Linfo_string           # DW_AT_name
                                         # DW_AT_external
@@ -17,11 +88,28 @@ sym:
     .byte   0                       # End Of Children Mark
 .Lcu_end:
 
+    .long   .Lcu2_end - .Lcu2_start # Length of Unit
+.Lcu2_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
+    .long   .Lunit2                 # DW_AT_stmt_list
+    .byte   2                       # Abbrev [2] 0x2a:0x15 DW_TAG_variable
+    .long   .Linfo2_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
+.Lcu2_end:
+
 .section .debug_abbrev,"",@progbits
 .Lsection_abbrev:
     .byte   1                       # Abbreviation Code
     .byte   17                      # DW_TAG_compile_unit
     .byte   1                       # DW_CHILDREN_yes
+    .byte   16                      # DW_AT_stmt_list
+    .byte   23                      # DW_FORM_sec_offset
     .byte   0                       # EOM(1)
     .byte   0                       # EOM(2)
     .byte   2                       # Abbreviation Code
@@ -42,3 +130,5 @@ sym:
 .section .debug_str,"MS",@progbits,1
 .Linfo_string:
     .asciz "sym"
+.Linfo2_string:
+    .asciz "sym2"

diff --git a/lld/test/ELF/no-line-parser-errors-if-empty-section.s b/lld/test/ELF/no-line-parser-errors-if-empty-section.s
new file mode 100644 (file)
index 0000000..56b255e
--- /dev/null
+++ b/lld/test/ELF/no-line-parser-errors-if-empty-section.s
@@ -0,0 +1,21 @@
+# REQUIRES: x86
+
+# LLD uses the debug data to get information for error messages, if possible.
+# However, if the debug line section is empty, we should not attempt to parse
+# it, as that would result in errors from the parser.
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: not ld.lld %t.o -o %t.elf 2>&1 | FileCheck %s
+
+# CHECK-NOT: warning:
+# CHECK-NOT: error:
+# CHECK: error: undefined symbol: undefined
+# CHECK-NEXT: {{.*}}.o:(.text+0x1)
+# CHECK-NOT: warning:
+# CHECK-NOT: error:
+
+.globl _start
+_start:
+    callq undefined
+
+.section .debug_line,"",@progbits

diff --git a/lld/test/ELF/no-line-parser-errors-if-no-section.s b/lld/test/ELF/no-line-parser-errors-if-no-section.s
new file mode 100644 (file)
index 0000000..9210d85
--- /dev/null
+++ b/lld/test/ELF/no-line-parser-errors-if-no-section.s
@@ -0,0 +1,19 @@
+# REQUIRES: x86
+
+# LLD uses the debug data to get information for error messages, if possible.
+# However, if there is no debug line section, we should not attempt to parse
+# it, as that would result in errors from the parser.
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: not ld.lld %t.o -o %t.elf 2>&1 | FileCheck %s
+
+# CHECK-NOT: warning:
+# CHECK-NOT: error:
+# CHECK: error: undefined symbol: undefined
+# CHECK-NEXT: {{.*}}.o:(.text+0x1)
+# CHECK-NOT: warning:
+# CHECK-NOT: error:
+
+.globl _start
+_start:
+    callq undefined

diff --git a/lld/test/ELF/undef.s b/lld/test/ELF/undef.s
index aabcbbc..07e3b68 100644 (file)
--- a/lld/test/ELF/undef.s
+++ b/lld/test/ELF/undef.s
@@ -34,9 +34,19 @@
 # CHECK: >>> referenced by undef-debug.s:11 (dir{{/|\\}}undef-debug.s:11)
 # CHECK: >>>               {{.*}}.o:(.text.2+0x0)
 
+# Show that all line table problems are mentioned as soon as the object's line information
+# is requested, even if that particular part of the line information is not currently required.
+# CHECK: warning: parsing line table prologue at 0x00000000 should have ended at 0x00000038 but it ended at 0x00000037
+# CHECK: warning: last sequence in debug line table is not terminated!
 # CHECK: error: undefined symbol: zed6
 # CHECK: >>> referenced by {{.*}}tmp4.o:(.text+0x0)
 
+# Show that a problem with one line table's information doesn't affect getting information from
+# a different one in the same object.
+# CHECK: error: undefined symbol: zed7
+# CHECK: >>> referenced by undef-bad-debug2.s:11 (dir2{{/|\\}}undef-bad-debug2.s:11)
+# CHECK: >>>               {{.*}}tmp4.o:(.text+0x8)
+
 # 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