llvm-symbolizer: Support loclist in FRAME.

Summary:
Support location lists in FRAME command.
These are used for the majority of local variables in optimized code.
Also support DW_OP_breg in addition to DW_OP_fbreg when it refers to the
same register as DW_AT_frame_base.

Reviewers: pcc, jdoerfert

Subscribers: srhines, hiraditya, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70629

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 012bab3..0084d31 100644 (file)
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -1043,6 +1043,52 @@ static Optional<uint64_t> getTypeSize(DWARFDie Type, uint64_t PointerSize) {
   return Optional<uint64_t>();
 }
 
+static Optional<int64_t>
+getExpressionFrameOffset(ArrayRef<uint8_t> Expr,
+                         Optional<unsigned> FrameBaseReg) {
+  if (!Expr.empty() &&
+      (Expr[0] == DW_OP_fbreg ||
+       (FrameBaseReg && Expr[0] == DW_OP_breg0 + *FrameBaseReg))) {
+    unsigned Count;
+    int64_t Offset = decodeSLEB128(Expr.data() + 1, &Count, Expr.end());
+    // A single DW_OP_fbreg or DW_OP_breg.
+    if (Expr.size() == Count + 1)
+      return Offset;
+    // Same + DW_OP_deref (Fortran arrays look like this).
+    if (Expr.size() == Count + 2 && Expr[Count + 1] == DW_OP_deref)
+      return Offset;
+    // Fallthrough. Do not accept ex. (DW_OP_breg W29, DW_OP_stack_value)
+  }
+  return None;
+}
+
+static Optional<int64_t>
+getLocationFrameOffset(DWARFCompileUnit *CU, DWARFFormValue &FormValue,
+                       Optional<unsigned> FrameBaseReg) {
+  if (Optional<ArrayRef<uint8_t>> Location = FormValue.getAsBlock()) {
+    return getExpressionFrameOffset(*Location, FrameBaseReg);
+  } else if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
+    uint64_t Offset = *FormValue.getAsSectionOffset();
+    const DWARFLocationTable &LocTable = CU->getLocationTable();
+    Optional<int64_t> FrameOffset;
+    Error E = LocTable.visitLocationList(
+        &Offset, [&](const DWARFLocationEntry &Entry) {
+          if (Entry.Kind == dwarf::DW_LLE_base_address ||
+              Entry.Kind == dwarf::DW_LLE_base_addressx ||
+              Entry.Kind == dwarf::DW_LLE_end_of_list) {
+            return true;
+          }
+          if ((FrameOffset = getExpressionFrameOffset(Entry.Loc, FrameBaseReg)))
+            return false;
+          return true;
+        });
+    if (E)
+      return None;
+    return FrameOffset;
+  }
+  return None;
+}
+
 void DWARFContext::addLocalsForDie(DWARFCompileUnit *CU, DWARFDie Subprogram,
                                    DWARFDie Die, std::vector<DILocal> &Result) {
   if (Die.getTag() == DW_TAG_variable ||
@@ -1051,11 +1097,17 @@ void DWARFContext::addLocalsForDie(DWARFCompileUnit *CU, DWARFDie Subprogram,
     if (auto NameAttr = Subprogram.find(DW_AT_name))
       if (Optional<const char *> Name = NameAttr->getAsCString())
         Local.FunctionName = *Name;
+
+    Optional<unsigned> FrameBaseReg;
+    if (auto FrameBase = Subprogram.find(DW_AT_frame_base))
+      if (Optional<ArrayRef<uint8_t>> Expr = FrameBase->getAsBlock())
+        if (!Expr->empty() && (*Expr)[0] >= DW_OP_reg0 &&
+            (*Expr)[0] <= DW_OP_reg31) {
+          FrameBaseReg = (*Expr)[0] - DW_OP_reg0;
+        }
     if (auto LocationAttr = Die.find(DW_AT_location))
-      if (Optional<ArrayRef<uint8_t>> Location = LocationAttr->getAsBlock())
-        if (!Location->empty() && (*Location)[0] == DW_OP_fbreg)
-          Local.FrameOffset =
-              decodeSLEB128(Location->data() + 1, nullptr, Location->end());
+      Local.FrameOffset = getLocationFrameOffset(CU, *LocationAttr, FrameBaseReg);
+
     if (auto TagOffsetAttr = Die.find(DW_AT_LLVM_tag_offset))
       Local.TagOffset = TagOffsetAttr->getAsUnsignedConstant();
 

diff --git a/llvm/test/tools/llvm-symbolizer/frame-loclist.s b/llvm/test/tools/llvm-symbolizer/frame-loclist.s
new file mode 100644 (file)
index 0000000..91e35c3
--- /dev/null
+++ b/llvm/test/tools/llvm-symbolizer/frame-loclist.s
@@ -0,0 +1,588 @@
+// Test various single-location and location list formats.
+// REQUIRES: aarch64-registered-target
+
+// RUN: llvm-mc -filetype=obj -triple=aarch64-linux-android -o %t.o %s
+// RUN: echo -e 'FRAME %t.o 0x4\nFRAME %t.o 0x24\nFRAME %t.o 0x48\nFRAME %t.o 0x6a\nFRAME %t.o 0x9a' | llvm-symbolizer | FileCheck %s
+
+// DW_AT_location        (DW_OP_breg29 W29-4)
+// CHECK:      func00
+// CHECK-NEXT: x
+// CHECK-NEXT: /tmp/dbg.cc:7
+// CHECK-NEXT: -4 4 ??
+
+// DW_AT_location        (DW_OP_fbreg -4)
+// CHECK:      func0{{$}}
+// CHECK-NEXT: x
+// CHECK-NEXT: /tmp/dbg.cc:12
+// CHECK-NEXT: -4 4 ??
+
+// DW_AT_location        (0x00000000: 
+//   [0x000000000000004c, 0x0000000000000058): DW_OP_breg29 W29-4
+//   [0x0000000000000058, 0x000000000000005c): DW_OP_reg0 W0)
+// CHECK:      func1
+// CHECK-NEXT: x
+// CHECK-NEXT: /tmp/dbg.cc:17
+// CHECK-NEXT: -4 4 ??
+
+// DW_AT_location        (0x00000037: 
+//    [0x0000000000000078, 0x0000000000000080): DW_OP_consts +1, DW_OP_stack_value
+//    [0x0000000000000080, 0x0000000000000088): DW_OP_breg29 W29-4
+//    [0x0000000000000088, 0x000000000000008c): DW_OP_reg0 W0)
+// CHECK:      func2
+// CHECK-NEXT: x
+// CHECK-NEXT: /tmp/dbg.cc:23
+// CHECK-NEXT: -4 4 ??
+
+// location lost
+// DW_AT_location        (0x00000083: 
+//    [0x00000000000000a8, 0x00000000000000b8): DW_OP_consts +1, DW_OP_stack_value
+//    [0x00000000000000b8, 0x00000000000000bc): DW_OP_reg0 W0)
+// CHECK:      func3
+// CHECK-NEXT: x
+// CHECK-NEXT: /tmp/dbg.cc:29
+// CHECK-NEXT: ?? 4 ??
+
+       .text
+       .file   "dbg.cc"
+       .file   1 "/tmp" "dbg.cc"
+       .globl  func00                  // -- Begin function func00
+       .p2align        2
+       .type   func00,@function
+func00:                                 // @func00
+.Lfunc_begin0:
+       .loc    1 6 0                   // /tmp/dbg.cc:6:0
+       .cfi_startproc
+// %bb.0:                               // %entry
+       sub     sp, sp, #32             // =32
+       stp     x29, x30, [sp, #16]     // 16-byte Folded Spill
+       add     x29, sp, #16            // =16
+       .cfi_def_cfa w29, 16
+       .cfi_offset w30, -8
+       .cfi_offset w29, -16
+.Ltmp0:
+       //DEBUG_VALUE: func00:x <- [DW_OP_constu 4, DW_OP_minus, DW_OP_deref] $fp
+       .loc    1 8 3 prologue_end      // /tmp/dbg.cc:8:3
+       sub     x0, x29, #4             // =4
+       bl      use
+.Ltmp1:
+       .loc    1 9 1                   // /tmp/dbg.cc:9:1
+       ldp     x29, x30, [sp, #16]     // 16-byte Folded Reload
+       add     sp, sp, #32             // =32
+       ret
+.Ltmp2:
+.Lfunc_end0:
+       .size   func00, .Lfunc_end0-func00
+       .cfi_endproc
+                                        // -- End function
+       .globl  func0                   // -- Begin function func0
+       .p2align        2
+       .type   func0,@function
+func0:                                  // @func0
+.Lfunc_begin1:
+       .loc    1 11 0                  // /tmp/dbg.cc:11:0
+       .cfi_startproc
+// %bb.0:                               // %entry
+       sub     sp, sp, #32             // =32
+       stp     x29, x30, [sp, #16]     // 16-byte Folded Spill
+       add     x29, sp, #16            // =16
+       .cfi_def_cfa w29, 16
+       .cfi_offset w30, -8
+       .cfi_offset w29, -16
+.Ltmp3:
+       //DEBUG_VALUE: func0:x <- [DW_OP_constu 4, DW_OP_minus, DW_OP_deref] $fp
+       .loc    1 13 3 prologue_end     // /tmp/dbg.cc:13:3
+       sub     x0, x29, #4             // =4
+       bl      use
+.Ltmp4:
+       .loc    1 14 1                  // /tmp/dbg.cc:14:1
+       ldp     x29, x30, [sp, #16]     // 16-byte Folded Reload
+       add     sp, sp, #32             // =32
+       ret
+.Ltmp5:
+.Lfunc_end1:
+       .size   func0, .Lfunc_end1-func0
+       .cfi_endproc
+                                        // -- End function
+       .globl  func1                   // -- Begin function func1
+       .p2align        2
+       .type   func1,@function
+func1:                                  // @func1
+.Lfunc_begin2:
+       .loc    1 16 0                  // /tmp/dbg.cc:16:0
+       .cfi_startproc
+// %bb.0:                               // %entry
+       sub     sp, sp, #32             // =32
+       stp     x29, x30, [sp, #16]     // 16-byte Folded Spill
+       add     x29, sp, #16            // =16
+       .cfi_def_cfa w29, 16
+       .cfi_offset w30, -8
+       .cfi_offset w29, -16
+.Ltmp6:
+       //DEBUG_VALUE: func1:x <- [DW_OP_constu 4, DW_OP_minus, DW_OP_deref] $fp
+       .loc    1 18 3 prologue_end     // /tmp/dbg.cc:18:3
+       sub     x0, x29, #4             // =4
+       bl      use
+.Ltmp7:
+       .loc    1 19 8                  // /tmp/dbg.cc:19:8
+       ldur    w0, [x29, #-4]
+.Ltmp8:
+       //DEBUG_VALUE: func1:x <- $w0
+       .loc    1 19 3 is_stmt 0        // /tmp/dbg.cc:19:3
+       bl      usev
+.Ltmp9:
+       .loc    1 20 1 is_stmt 1        // /tmp/dbg.cc:20:1
+       ldp     x29, x30, [sp, #16]     // 16-byte Folded Reload
+       add     sp, sp, #32             // =32
+       ret
+.Ltmp10:
+.Lfunc_end2:
+       .size   func1, .Lfunc_end2-func1
+       .cfi_endproc
+                                        // -- End function
+       .globl  func2                   // -- Begin function func2
+       .p2align        2
+       .type   func2,@function
+func2:                                  // @func2
+.Lfunc_begin3:
+       .loc    1 22 0                  // /tmp/dbg.cc:22:0
+       .cfi_startproc
+// %bb.0:                               // %entry
+       sub     sp, sp, #32             // =32
+       stp     x29, x30, [sp, #16]     // 16-byte Folded Spill
+       add     x29, sp, #16            // =16
+       .cfi_def_cfa w29, 16
+       .cfi_offset w30, -8
+       .cfi_offset w29, -16
+       mov     w8, #1
+.Ltmp11:
+       //DEBUG_VALUE: func2:x <- 1
+       .loc    1 24 3 prologue_end     // /tmp/dbg.cc:24:3
+       sub     x0, x29, #4             // =4
+       .loc    1 23 7                  // /tmp/dbg.cc:23:7
+       stur    w8, [x29, #-4]
+.Ltmp12:
+       //DEBUG_VALUE: func2:x <- [DW_OP_constu 4, DW_OP_minus, DW_OP_deref] $fp
+       .loc    1 24 3                  // /tmp/dbg.cc:24:3
+       bl      use
+.Ltmp13:
+       .loc    1 25 8                  // /tmp/dbg.cc:25:8
+       ldur    w0, [x29, #-4]
+.Ltmp14:
+       //DEBUG_VALUE: func2:x <- $w0
+       .loc    1 25 3 is_stmt 0        // /tmp/dbg.cc:25:3
+       bl      usev
+.Ltmp15:
+       .loc    1 26 1 is_stmt 1        // /tmp/dbg.cc:26:1
+       ldp     x29, x30, [sp, #16]     // 16-byte Folded Reload
+       add     sp, sp, #32             // =32
+       ret
+.Ltmp16:
+.Lfunc_end3:
+       .size   func2, .Lfunc_end3-func2
+       .cfi_endproc
+                                        // -- End function
+       .globl  func3                   // -- Begin function func3
+       .p2align        2
+       .type   func3,@function
+func3:                                  // @func3
+.Lfunc_begin4:
+       .loc    1 28 0                  // /tmp/dbg.cc:28:0
+       .cfi_startproc
+// %bb.0:                               // %entry
+       sub     sp, sp, #32             // =32
+       stp     x29, x30, [sp, #16]     // 16-byte Folded Spill
+       add     x29, sp, #16            // =16
+       .cfi_def_cfa w29, 16
+       .cfi_offset w30, -8
+       .cfi_offset w29, -16
+       mov     w8, #1
+.Ltmp17:
+       //DEBUG_VALUE: func3:x <- 1
+       .loc    1 30 3 prologue_end     // /tmp/dbg.cc:30:3
+       sub     x0, x29, #4             // =4
+       .loc    1 29 7                  // /tmp/dbg.cc:29:7
+       stur    w8, [x29, #-4]
+       .loc    1 30 3                  // /tmp/dbg.cc:30:3
+       bl      useV
+.Ltmp18:
+       .loc    1 31 8                  // /tmp/dbg.cc:31:8
+       ldur    w0, [x29, #-4]
+.Ltmp19:
+       //DEBUG_VALUE: func3:x <- $w0
+       .loc    1 31 3 is_stmt 0        // /tmp/dbg.cc:31:3
+       bl      usev
+.Ltmp20:
+       .loc    1 32 1 is_stmt 1        // /tmp/dbg.cc:32:1
+       ldp     x29, x30, [sp, #16]     // 16-byte Folded Reload
+       add     sp, sp, #32             // =32
+       ret
+.Ltmp21:
+.Lfunc_end4:
+       .size   func3, .Lfunc_end4-func3
+       .cfi_endproc
+                                        // -- End function
+       .section        .debug_str,"MS",@progbits,1
+.Linfo_string0:
+       .asciz  "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 5d25e153457e7bdd4181ab7496402a565a5b9370)" // string offset=0
+.Linfo_string1:
+       .asciz  "/tmp/dbg.cc"           // string offset=101
+.Linfo_string2:
+       .asciz  "/code/build-llvm-cmake" // string offset=113
+.Linfo_string3:
+       .asciz  "use"                   // string offset=136
+.Linfo_string4:
+       .asciz  "int"                   // string offset=140
+.Linfo_string5:
+       .asciz  "usev"                  // string offset=144
+.Linfo_string6:
+       .asciz  "useV"                  // string offset=149
+.Linfo_string7:
+       .asciz  "func00"                // string offset=154
+.Linfo_string8:
+       .asciz  "func0"                 // string offset=161
+.Linfo_string9:
+       .asciz  "func1"                 // string offset=167
+.Linfo_string10:
+       .asciz  "func2"                 // string offset=173
+.Linfo_string11:
+       .asciz  "func3"                 // string offset=179
+.Linfo_string12:
+       .asciz  "x"                     // string offset=185
+       .section        .debug_loc,"",@progbits
+.Ldebug_loc0:
+       .xword  .Ltmp6-.Lfunc_begin0
+       .xword  .Ltmp8-.Lfunc_begin0
+       .hword  2                       // Loc expr size
+       .byte   141                     // DW_OP_breg29
+       .byte   124                     // -4
+       .xword  .Ltmp8-.Lfunc_begin0
+       .xword  .Ltmp9-.Lfunc_begin0
+       .hword  1                       // Loc expr size
+       .byte   80                      // DW_OP_reg0
+       .xword  0
+       .xword  0
+.Ldebug_loc1:
+       .xword  .Ltmp11-.Lfunc_begin0
+       .xword  .Ltmp12-.Lfunc_begin0
+       .hword  3                       // Loc expr size
+       .byte   17                      // DW_OP_consts
+       .byte   1                       // 1
+       .byte   159                     // DW_OP_stack_value
+       .xword  .Ltmp12-.Lfunc_begin0
+       .xword  .Ltmp14-.Lfunc_begin0
+       .hword  2                       // Loc expr size
+       .byte   141                     // DW_OP_breg29
+       .byte   124                     // -4
+       .xword  .Ltmp14-.Lfunc_begin0
+       .xword  .Ltmp15-.Lfunc_begin0
+       .hword  1                       // Loc expr size
+       .byte   80                      // DW_OP_reg0
+       .xword  0
+       .xword  0
+.Ldebug_loc2:
+       .xword  .Ltmp17-.Lfunc_begin0
+       .xword  .Ltmp19-.Lfunc_begin0
+       .hword  3                       // Loc expr size
+       .byte   17                      // DW_OP_consts
+       .byte   1                       // 1
+       .byte   159                     // DW_OP_stack_value
+       .xword  .Ltmp19-.Lfunc_begin0
+       .xword  .Ltmp20-.Lfunc_begin0
+       .hword  1                       // Loc expr size
+       .byte   80                      // DW_OP_reg0
+       .xword  0
+       .xword  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
+       .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   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   60                      // DW_AT_declaration
+       .byte   25                      // DW_FORM_flag_present
+       .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   73                      // DW_AT_type
+       .byte   19                      // DW_FORM_ref4
+       .byte   0                       // EOM(1)
+       .byte   0                       // EOM(2)
+       .byte   4                       // Abbreviation Code
+       .byte   15                      // DW_TAG_pointer_type
+       .byte   0                       // DW_CHILDREN_no
+       .byte   73                      // DW_AT_type
+       .byte   19                      // DW_FORM_ref4
+       .byte   0                       // EOM(1)
+       .byte   0                       // EOM(2)
+       .byte   5                       // 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   6                       // Abbreviation Code
+       .byte   15                      // DW_TAG_pointer_type
+       .byte   0                       // DW_CHILDREN_no
+       .byte   0                       // EOM(1)
+       .byte   0                       // EOM(2)
+       .byte   7                       // 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
+       .ascii  "\227B"                 // DW_AT_GNU_all_call_sites
+       .byte   25                      // DW_FORM_flag_present
+       .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   63                      // DW_AT_external
+       .byte   25                      // DW_FORM_flag_present
+       .byte   0                       // EOM(1)
+       .byte   0                       // EOM(2)
+       .byte   8                       // Abbreviation Code
+       .byte   52                      // DW_TAG_variable
+       .byte   0                       // DW_CHILDREN_no
+       .byte   2                       // DW_AT_location
+       .byte   24                      // DW_FORM_exprloc
+       .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   9                       // Abbreviation Code
+       .ascii  "\211\202\001"          // DW_TAG_GNU_call_site
+       .byte   0                       // DW_CHILDREN_no
+       .byte   49                      // DW_AT_abstract_origin
+       .byte   19                      // DW_FORM_ref4
+       .byte   17                      // DW_AT_low_pc
+       .byte   1                       // DW_FORM_addr
+       .byte   0                       // EOM(1)
+       .byte   0                       // EOM(2)
+       .byte   10                      // Abbreviation Code
+       .byte   52                      // DW_TAG_variable
+       .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   0                       // EOM(3)
+       .section        .debug_info,"",@progbits
+.Lcu_begin0:
+       .word   .Ldebug_info_end0-.Ldebug_info_start0 // Length of Unit
+.Ldebug_info_start0:
+       .hword  4                       // DWARF version number
+       .word   .debug_abbrev           // Offset Into Abbrev. Section
+       .byte   8                       // Address Size (in bytes)
+       .byte   1                       // Abbrev [1] 0xb:0x173 DW_TAG_compile_unit
+       .word   .Linfo_string0          // DW_AT_producer
+       .hword  33                      // DW_AT_language
+       .word   .Linfo_string1          // DW_AT_name
+       .word   .Lline_table_start0     // DW_AT_stmt_list
+       .word   .Linfo_string2          // DW_AT_comp_dir
+       .xword  .Lfunc_begin0           // DW_AT_low_pc
+       .word   .Lfunc_end4-.Lfunc_begin0 // DW_AT_high_pc
+       .byte   2                       // Abbrev [2] 0x2a:0xd DW_TAG_subprogram
+       .word   .Linfo_string3          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   3                       // DW_AT_decl_line
+                                        // DW_AT_declaration
+                                        // DW_AT_external
+       .byte   3                       // Abbrev [3] 0x31:0x5 DW_TAG_formal_parameter
+       .word   55                      // DW_AT_type
+       .byte   0                       // End Of Children Mark
+       .byte   4                       // Abbrev [4] 0x37:0x5 DW_TAG_pointer_type
+       .word   60                      // DW_AT_type
+       .byte   5                       // Abbrev [5] 0x3c:0x7 DW_TAG_base_type
+       .word   .Linfo_string4          // DW_AT_name
+       .byte   5                       // DW_AT_encoding
+       .byte   4                       // DW_AT_byte_size
+       .byte   2                       // Abbrev [2] 0x43:0xd DW_TAG_subprogram
+       .word   .Linfo_string5          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   4                       // DW_AT_decl_line
+                                        // DW_AT_declaration
+                                        // DW_AT_external
+       .byte   3                       // Abbrev [3] 0x4a:0x5 DW_TAG_formal_parameter
+       .word   60                      // DW_AT_type
+       .byte   0                       // End Of Children Mark
+       .byte   2                       // Abbrev [2] 0x50:0xd DW_TAG_subprogram
+       .word   .Linfo_string6          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   2                       // DW_AT_decl_line
+                                        // DW_AT_declaration
+                                        // DW_AT_external
+       .byte   3                       // Abbrev [3] 0x57:0x5 DW_TAG_formal_parameter
+       .word   93                      // DW_AT_type
+       .byte   0                       // End Of Children Mark
+       .byte   6                       // Abbrev [6] 0x5d:0x1 DW_TAG_pointer_type
+       .byte   7                       // Abbrev [7] 0x5e:0x31 DW_TAG_subprogram
+       .xword  .Lfunc_begin0           // DW_AT_low_pc
+       .word   .Lfunc_end0-.Lfunc_begin0 // DW_AT_high_pc
+       .byte   1                       // DW_AT_frame_base
+       .byte   109
+                                        // DW_AT_GNU_all_call_sites
+       .word   .Linfo_string7          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   6                       // DW_AT_decl_line
+                                        // DW_AT_external
+       .byte   8                       // Abbrev [8] 0x73:0xe DW_TAG_variable
+       .byte   2                       // DW_AT_location
+       .byte   141                     // DW_OP_breg29
+       .byte   124                     // -4
+       .word   .Linfo_string12         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   7                       // DW_AT_decl_line
+       .word   60                      // DW_AT_type
+       .byte   9                       // Abbrev [9] 0x81:0xd DW_TAG_GNU_call_site
+       .word   42                      // DW_AT_abstract_origin
+       .xword  .Ltmp1                  // DW_AT_low_pc
+       .byte   0                       // End Of Children Mark
+       .byte   7                       // Abbrev [7] 0x8f:0x31 DW_TAG_subprogram
+       .xword  .Lfunc_begin1           // DW_AT_low_pc
+       .word   .Lfunc_end1-.Lfunc_begin1 // DW_AT_high_pc
+       .byte   1                       // DW_AT_frame_base
+       .byte   109
+                                        // DW_AT_GNU_all_call_sites
+       .word   .Linfo_string8          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   11                      // DW_AT_decl_line
+                                        // DW_AT_external
+       .byte   8                       // Abbrev [8] 0xa4:0xe DW_TAG_variable
+       .byte   2                       // DW_AT_location
+       .byte   145
+       .byte   124
+       .word   .Linfo_string12         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   12                      // DW_AT_decl_line
+       .word   60                      // DW_AT_type
+       .byte   9                       // Abbrev [9] 0xb2:0xd DW_TAG_GNU_call_site
+       .word   42                      // DW_AT_abstract_origin
+       .xword  .Ltmp4                  // DW_AT_low_pc
+       .byte   0                       // End Of Children Mark
+       .byte   7                       // Abbrev [7] 0xc0:0x3f DW_TAG_subprogram
+       .xword  .Lfunc_begin2           // DW_AT_low_pc
+       .word   .Lfunc_end2-.Lfunc_begin2 // DW_AT_high_pc
+       .byte   1                       // DW_AT_frame_base
+       .byte   109
+                                        // DW_AT_GNU_all_call_sites
+       .word   .Linfo_string9          // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   16                      // DW_AT_decl_line
+                                        // DW_AT_external
+       .byte   10                      // Abbrev [10] 0xd5:0xf DW_TAG_variable
+       .word   .Ldebug_loc0            // DW_AT_location
+       .word   .Linfo_string12         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   17                      // DW_AT_decl_line
+       .word   60                      // DW_AT_type
+       .byte   9                       // Abbrev [9] 0xe4:0xd DW_TAG_GNU_call_site
+       .word   42                      // DW_AT_abstract_origin
+       .xword  .Ltmp7                  // DW_AT_low_pc
+       .byte   9                       // Abbrev [9] 0xf1:0xd DW_TAG_GNU_call_site
+       .word   67                      // DW_AT_abstract_origin
+       .xword  .Ltmp9                  // DW_AT_low_pc
+       .byte   0                       // End Of Children Mark
+       .byte   7                       // Abbrev [7] 0xff:0x3f DW_TAG_subprogram
+       .xword  .Lfunc_begin3           // DW_AT_low_pc
+       .word   .Lfunc_end3-.Lfunc_begin3 // DW_AT_high_pc
+       .byte   1                       // DW_AT_frame_base
+       .byte   109
+                                        // DW_AT_GNU_all_call_sites
+       .word   .Linfo_string10         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   22                      // DW_AT_decl_line
+                                        // DW_AT_external
+       .byte   10                      // Abbrev [10] 0x114:0xf DW_TAG_variable
+       .word   .Ldebug_loc1            // DW_AT_location
+       .word   .Linfo_string12         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   23                      // DW_AT_decl_line
+       .word   60                      // DW_AT_type
+       .byte   9                       // Abbrev [9] 0x123:0xd DW_TAG_GNU_call_site
+       .word   42                      // DW_AT_abstract_origin
+       .xword  .Ltmp13                 // DW_AT_low_pc
+       .byte   9                       // Abbrev [9] 0x130:0xd DW_TAG_GNU_call_site
+       .word   67                      // DW_AT_abstract_origin
+       .xword  .Ltmp15                 // DW_AT_low_pc
+       .byte   0                       // End Of Children Mark
+       .byte   7                       // Abbrev [7] 0x13e:0x3f DW_TAG_subprogram
+       .xword  .Lfunc_begin4           // DW_AT_low_pc
+       .word   .Lfunc_end4-.Lfunc_begin4 // DW_AT_high_pc
+       .byte   1                       // DW_AT_frame_base
+       .byte   109
+                                        // DW_AT_GNU_all_call_sites
+       .word   .Linfo_string11         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   28                      // DW_AT_decl_line
+                                        // DW_AT_external
+       .byte   10                      // Abbrev [10] 0x153:0xf DW_TAG_variable
+       .word   .Ldebug_loc2            // DW_AT_location
+       .word   .Linfo_string12         // DW_AT_name
+       .byte   1                       // DW_AT_decl_file
+       .byte   29                      // DW_AT_decl_line
+       .word   60                      // DW_AT_type
+       .byte   9                       // Abbrev [9] 0x162:0xd DW_TAG_GNU_call_site
+       .word   80                      // DW_AT_abstract_origin
+       .xword  .Ltmp18                 // DW_AT_low_pc
+       .byte   9                       // Abbrev [9] 0x16f:0xd DW_TAG_GNU_call_site
+       .word   67                      // DW_AT_abstract_origin
+       .xword  .Ltmp20                 // DW_AT_low_pc
+       .byte   0                       // End Of Children Mark
+       .byte   0                       // End Of Children Mark
+.Ldebug_info_end0:
+       .ident  "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 5d25e153457e7bdd4181ab7496402a565a5b9370)"
+       .section        ".note.GNU-stack","",@progbits
+       .section        .debug_line,"",@progbits
+.Lline_table_start0: