Make DWARFUnit use the dwo_id from the DWARF5 CU header.

In split DWARF v5 files, the DWO id is no longer in the DW_AT_GNU_dwo_id
attribute. It's in the CU header instead. This change makes lldb look in
both places.

Differential Revision: https://reviews.llvm.org/D93444

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
index d0cfb5f..a761dd3 100644 (file)
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -34,7 +34,8 @@ DWARFUnit::DWARFUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
                      const DWARFAbbreviationDeclarationSet &abbrevs,
                      DIERef::Section section, bool is_dwo)
     : UserID(uid), m_dwarf(dwarf), m_header(header), m_abbrevs(&abbrevs),
-      m_cancel_scopes(false), m_section(section), m_is_dwo(is_dwo) {}
+      m_cancel_scopes(false), m_section(section), m_is_dwo(is_dwo),
+      m_dwo_id(header.GetDWOId()) {}
 
 DWARFUnit::~DWARFUnit() = default;
 
@@ -284,6 +285,11 @@ void DWARFUnit::SetDwoStrOffsetsBase() {
   SetStrOffsetsBase(baseOffset);
 }
 
+uint64_t DWARFUnit::GetDWOId() {
+  ExtractUnitDIEIfNeeded();
+  return m_dwo_id;
+}
+
 // m_die_array_mutex must be already held as read/write.
 void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
   llvm::Optional<uint64_t> addr_base, gnu_addr_base, ranges_base,
@@ -337,6 +343,9 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
     case DW_AT_GNU_ranges_base:
       gnu_ranges_base = form_value.Unsigned();
       break;
+    case DW_AT_GNU_dwo_id:
+      m_dwo_id = form_value.Unsigned();
+      break;
     }
   }
 
@@ -350,9 +359,8 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
   if (!dwo_symbol_file)
     return;
 
-  uint64_t main_dwo_id =
-      cu_die.GetAttributeValueAsUnsigned(this, DW_AT_GNU_dwo_id, 0);
-  DWARFUnit *dwo_cu = dwo_symbol_file->GetDWOCompileUnitForHash(main_dwo_id);
+  DWARFUnit *dwo_cu = dwo_symbol_file->GetDWOCompileUnitForHash(m_dwo_id);
+
   if (!dwo_cu)
     return; // Can't fetch the compile unit from the dwo file.
   dwo_cu->SetUserData(this);
@@ -788,7 +796,8 @@ DWARFUnitHeader::extract(const DWARFDataExtractor &data,
     header.m_unit_type = data.GetU8(offset_ptr);
     header.m_addr_size = data.GetU8(offset_ptr);
     header.m_abbr_offset = data.GetDWARFOffset(offset_ptr);
-    if (header.m_unit_type == llvm::dwarf::DW_UT_skeleton)
+    if (header.m_unit_type == llvm::dwarf::DW_UT_skeleton ||
+        header.m_unit_type == llvm::dwarf::DW_UT_split_compile)
       header.m_dwo_id = data.GetU64(offset_ptr);
   } else {
     header.m_abbr_offset = data.GetDWARFOffset(offset_ptr);

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
index d600951..5739c36 100644 (file)
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
@@ -65,6 +65,7 @@ public:
   }
   uint64_t GetTypeHash() const { return m_type_hash; }
   dw_offset_t GetTypeOffset() const { return m_type_offset; }
+  uint64_t GetDWOId() const { return m_dwo_id; }
   bool IsTypeUnit() const {
     return m_unit_type == DW_UT_type || m_unit_type == DW_UT_split_type;
   }
@@ -88,6 +89,7 @@ public:
   virtual ~DWARFUnit();
 
   bool IsDWOUnit() { return m_is_dwo; }
+  uint64_t GetDWOId();
 
   void ExtractUnitDIEIfNeeded();
   void ExtractDIEsIfNeeded();
@@ -333,6 +335,8 @@ protected:
 
   const DIERef::Section m_section;
   bool m_is_dwo;
+  /// Value of DW_AT_GNU_dwo_id (v4) or dwo_id from CU header (v5).
+  uint64_t m_dwo_id;
 
 private:
   void ParseProducerInfo();

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
index 3aaa7d3..fcb51df 100644 (file)
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
@@ -49,8 +49,7 @@ DWARFCompileUnit *SymbolFileDWARFDwo::GetDWOCompileUnitForHash(uint64_t hash) {
   DWARFCompileUnit *cu = FindSingleCompileUnit();
   if (!cu)
     return nullptr;
-  if (hash !=
-      cu->GetUnitDIEOnly().GetAttributeValueAsUnsigned(DW_AT_GNU_dwo_id, 0))
+  if (hash != cu->GetDWOId())
     return nullptr;
   return cu;
 }

diff --git a/lldb/test/Shell/SymbolFile/DWARF/dwarf5-split.s b/lldb/test/Shell/SymbolFile/DWARF/dwarf5-split.s
new file mode 100644 (file)
index 0000000..720b319
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/dwarf5-split.s
@@ -0,0 +1,235 @@
+## This test checks that lldb reads debug info from a dwp file when the dwo_id
+## is in a DWARF5 CU header instead of a DW_AT_GNU_dwo_id attribute.
+
+# RUN: llvm-mc --filetype=obj --triple x86_64 %s -o %t --defsym MAIN=1
+# RUN: llvm-mc --filetype=obj --triple x86_64 %s -o %t.dwp
+# RUN: %lldb %t -o "target variable i" -b | FileCheck %s
+# CHECK: (int) i = 42
+
+.ifdef MAIN
+## Main file
+       .text
+       .globl  main                            # -- Begin function main
+main:                                   # @main
+.Lfunc_begin0:
+       pushq   %rbp
+       movq    %rsp, %rbp
+       xorl    %eax, %eax
+       popq    %rbp
+       retq
+.Lfunc_end0:
+                                        # -- End function
+       .data
+i:
+       .long   42                              # 0x2a
+
+
+       .section        .debug_abbrev,"",@progbits
+       .byte   1                               # Abbreviation Code
+       .byte   74                              # DW_TAG_skeleton_unit
+       .byte   0                               # DW_CHILDREN_no
+       .byte   118                             # DW_AT_dwo_name
+       .byte   8                               # DW_FORM_string
+       .byte   17                              # DW_AT_low_pc
+       .byte   27                              # DW_FORM_addrx
+       .byte   18                              # DW_AT_high_pc
+       .byte   6                               # DW_FORM_data4
+       .byte   115                             # DW_AT_addr_base
+       .byte   23                              # DW_FORM_sec_offset
+       .byte   0                               # EOM(1)
+       .byte   0                               # EOM(2)
+       .byte   0                               # EOM(3)
+
+
+       .section        .debug_info,"",@progbits
+.Lcu_begin0:
+       .long   .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+       .short  5                             # DWARF version number
+       .byte   4                               # DWARF Unit Type
+       .byte   8                               # Address Size (in bytes)
+       .long   .debug_abbrev                   # Offset Into Abbrev. Section
+       .quad   1026699901672188186             # dwo_id
+       .byte   1                               # Abbrev [1] 0x14:0x14 DW_TAG_skeleton_unit
+       .asciz "hello.dwo"                    # DW_AT_dwo_name
+       .byte   1                               # DW_AT_low_pc
+       .long   .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+       .long   .Laddr_table_base0              # DW_AT_addr_base
+.Ldebug_info_end0:
+
+       .section        .debug_addr,"",@progbits
+       .long   .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+       .short  5                               # DWARF version number
+       .byte   8                               # Address size
+       .byte   0                               # Segment selector size
+.Laddr_table_base0:
+       .quad   i
+       .quad   .Lfunc_begin0
+.Ldebug_addr_end0:
+
+.else
+## DWP file
+       .section        .debug_str_offsets.dwo,"e",@progbits
+       .long   28
+       .short  5
+       .short  0
+
+
+       .section        .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+       .asciz  "i"
+.Linfo_string1:
+       .asciz  "int"
+.Linfo_string2:
+       .asciz  "main"
+.Linfo_string3:
+       .asciz  "hand-tuned clang output"
+.Linfo_string4:
+       .asciz  "hello.c"
+.Linfo_string5:
+       .asciz  "hello.dwo"
+
+
+       .section        .debug_str_offsets.dwo,"e",@progbits
+       .long   .Linfo_string0-.debug_str.dwo
+       .long   .Linfo_string1-.debug_str.dwo
+       .long   .Linfo_string2-.debug_str.dwo
+       .long   .Linfo_string3-.debug_str.dwo
+       .long   .Linfo_string4-.debug_str.dwo
+       .long   .Linfo_string5-.debug_str.dwo
+.Lstr_offsets_end:
+
+
+       .section        .debug_info.dwo,"e",@progbits
+       .long   .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+       .short  5                               # DWARF version number
+       .byte   5                               # DWARF Unit Type
+       .byte   8                               # Address Size (in bytes)
+       .long   0                               # Offset Into Abbrev. Section
+       .quad   1026699901672188186             # dwo_id
+       .byte   1                               # Abbrev [1] 0x14:0x25 DW_TAG_compile_unit
+       .byte   3                               # DW_AT_producer
+       .short  12                              # DW_AT_language
+       .byte   4                               # DW_AT_name
+       .byte   5                               # DW_AT_dwo_name
+       .byte   2                               # Abbrev [2] 0x1a:0xb DW_TAG_variable
+       .byte   0                               # DW_AT_name
+       .long   37                              # DW_AT_type
+                                        # DW_AT_external
+       .byte   0                               # DW_AT_decl_file
+       .byte   2                               # DW_AT_decl_line
+       .byte   2                               # DW_AT_location
+       .byte   161
+       .byte   0
+       .byte   3                               # Abbrev [3] 0x25:0x4 DW_TAG_base_type
+       .byte   1                               # DW_AT_name
+       .byte   5                               # DW_AT_encoding
+       .byte   4                               # DW_AT_byte_size
+       .byte   4                               # Abbrev [4] 0x29:0xf DW_TAG_subprogram
+       .byte   1                               # DW_AT_low_pc
+       .long   8       # DW_AT_high_pc
+       .byte   1                               # DW_AT_frame_base
+       .byte   86
+       .byte   2                               # DW_AT_name
+       .byte   0                               # DW_AT_decl_file
+       .byte   3                               # DW_AT_decl_line
+       .long   37                              # DW_AT_type
+                                        # DW_AT_external
+       .byte   0                               # End Of Children Mark
+.Ldebug_info_dwo_end0:
+
+
+       .section        .debug_abbrev.dwo,"e",@progbits
+       .byte   1                               # Abbreviation Code
+       .byte   17                              # DW_TAG_compile_unit
+       .byte   1                               # DW_CHILDREN_yes
+       .byte   37                              # DW_AT_producer
+       .byte   37                              # DW_FORM_strx1
+       .byte   19                              # DW_AT_language
+       .byte   5                               # DW_FORM_data2
+       .byte   3                               # DW_AT_name
+       .byte   37                              # DW_FORM_strx1
+       .byte   118                             # DW_AT_dwo_name
+       .byte   37                              # DW_FORM_strx1
+       .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   37                              # DW_FORM_strx1
+       .byte   73                              # DW_AT_type
+       .byte   19                              # DW_FORM_ref4
+       .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   2                               # DW_AT_location
+       .byte   24                              # DW_FORM_exprloc
+       .byte   0                               # EOM(1)
+       .byte   0                               # EOM(2)
+       .byte   3                               # Abbreviation Code
+       .byte   36                              # DW_TAG_base_type
+       .byte   0                               # DW_CHILDREN_no
+       .byte   3                               # DW_AT_name
+       .byte   37                              # DW_FORM_strx1
+       .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   4                               # Abbreviation Code
+       .byte   46                              # DW_TAG_subprogram
+       .byte   0                               # DW_CHILDREN_no
+       .byte   17                              # DW_AT_low_pc
+       .byte   27                              # DW_FORM_addrx
+       .byte   18                              # DW_AT_high_pc
+       .byte   6                               # DW_FORM_data4
+       .byte   64                              # DW_AT_frame_base
+       .byte   24                              # DW_FORM_exprloc
+       .byte   3                               # DW_AT_name
+       .byte   37                              # DW_FORM_strx1
+       .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   0                               # EOM(3)
+.Ldebug_abbrev_end:
+
+.section .debug_cu_index,"",@progbits
+.short 5  # DWARF version number
+.short 0  # Reserved
+.long  3  # Section count
+.long  1  # Unit count
+.long  2 # Slot count
+
+.quad  1026699901672188186, 0 # Hash table
+.long  1, 0 # Index table
+
+## Table header
+.long 1   # DW_SECT_INFO
+.long 3   # DW_SECT_ABBREV
+.long 6   # DW_SECT_STR_OFFSETS
+
+## Offsets
+.long 0   # offset into .debug_info.dwo
+.long 0   # offset into .debug_abbrev.dwo
+.long 0   # offset into .debug_str_offsets.dwo
+
+## Sizes
+.long .Ldebug_info_dwo_end0 - .debug_info.dwo
+.long .Ldebug_abbrev_end - .debug_abbrev.dwo
+.long .Lstr_offsets_end - .debug_str_offsets.dwo
+
+.endif