[llvm] b538a2a - llvm-symbolizer: support DW_FORM_loclistx locations.

Evgenii Stepanov via llvm-commits llvm-commits at lists.llvm.org
Fri Dec 20 10:36:25 PST 2019


Author: Evgenii Stepanov
Date: 2019-12-20T10:36:14-08:00
New Revision: b538a2aa071485a1fc13a8ef583d31db3381fec0

URL: https://github.com/llvm/llvm-project/commit/b538a2aa071485a1fc13a8ef583d31db3381fec0
DIFF: https://github.com/llvm/llvm-project/commit/b538a2aa071485a1fc13a8ef583d31db3381fec0.diff

LOG: llvm-symbolizer: support DW_FORM_loclistx locations.

Summary:
With -gdwarf-5 local variable locations are emitted as DW_FORM_loclistx
form instead of the regular DW_FORM_sec_offset. Teach
DWARFDie::getLocations to understand the new format and use it in
llvm-symbolizer "FRAME" command.

Reviewers: pcc, jdoerfert

Subscribers: srhines, aprantl, hiraditya, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70756

Added: 
    llvm/test/DebugInfo/AArch64/frame-loclistx.s

Modified: 
    llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
    llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index b268d2e6aef5..e452c7636b18 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -1077,33 +1077,6 @@ getExpressionFrameOffset(ArrayRef<uint8_t> Expr,
   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 ||
@@ -1119,8 +1092,21 @@ void DWARFContext::addLocalsForDie(DWARFCompileUnit *CU, DWARFDie Subprogram,
             (*Expr)[0] <= DW_OP_reg31) {
           FrameBaseReg = (*Expr)[0] - DW_OP_reg0;
         }
-    if (auto LocationAttr = Die.find(DW_AT_location))
-      Local.FrameOffset = getLocationFrameOffset(CU, *LocationAttr, FrameBaseReg);
+
+    if (Expected<std::vector<DWARFLocationExpression>> Loc =
+            Die.getLocations(DW_AT_location)) {
+      for (const auto &Entry : *Loc) {
+        if (Optional<int64_t> FrameOffset =
+                getExpressionFrameOffset(Entry.Expr, FrameBaseReg)) {
+          Local.FrameOffset = *FrameOffset;
+          break;
+        }
+      }
+    } else {
+      // FIXME: missing DW_AT_location is OK here, but other errors should be
+      // reported to the user.
+      consumeError(Loc.takeError());
+    }
 
     if (auto TagOffsetAttr = Die.find(DW_AT_LLVM_tag_offset))
       Local.TagOffset = TagOffsetAttr->getAsUnsignedConstant();

diff  --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index 4b86359c04e3..558d8006501a 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -495,8 +495,18 @@ DWARFDie::getLocations(dwarf::Attribute Attr) const {
     return createStringError(inconvertibleErrorCode(), "No %s",
                              dwarf::AttributeString(Attr).data());
 
-  if (Optional<uint64_t> Off = Location->getAsSectionOffset())
-    return U->findLoclistFromOffset(*Off);
+  if (Optional<uint64_t> Off = Location->getAsSectionOffset()) {
+    uint64_t Offset = *Off;
+
+    if (Location->getForm() == DW_FORM_loclistx) {
+      if (auto LoclistOffset = U->getLoclistOffset(Offset))
+        Offset = *LoclistOffset;
+      else
+        return createStringError(inconvertibleErrorCode(),
+                                 "Loclist table not found");
+    }
+    return U->findLoclistFromOffset(Offset);
+  }
 
   if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
     return DWARFLocationExpressionsVector{

diff  --git a/llvm/test/DebugInfo/AArch64/frame-loclistx.s b/llvm/test/DebugInfo/AArch64/frame-loclistx.s
new file mode 100644
index 000000000000..aabb97633c60
--- /dev/null
+++ b/llvm/test/DebugInfo/AArch64/frame-loclistx.s
@@ -0,0 +1,305 @@
+// Test dwarf-5 DW_AT_location [DW_FORM_loclistx].
+
+// Built with "clang -c -target aarch64-linux -gdwarf-5 -O3 -S" from the following source:
+// void use(int *);
+// void f(void) {
+//   int x = 1;
+//   use(&x);
+// }
+
+// RUN: llvm-mc -filetype=obj -triple=aarch64-linux-android --dwarf-version=5 -o %t.o %s
+// RUN: echo 'FRAME %t.o 0x4'  | llvm-symbolizer | FileCheck %s
+
+// DW_AT_location        (indexed (0x0) loclist = 0x00000010:
+// [0x0000000000000010, 0x0000000000000018): DW_OP_consts +1, DW_OP_stack_value
+// [0x0000000000000018, 0x0000000000000028): DW_OP_breg29 W29-4)
+// CHECK:      f
+// CHECK-NEXT: x
+// CHECK-NEXT: {{.*}}dbg.c:3
+// CHECK-NEXT: -4 4 ??
+
+	.text
+	.file	"dbg.c"
+	.file	0 "/code/build-llvm-cmake" "/tmp/dbg.c" md5 0x87e53f5ae1de5f2c6ec0baa7fe683192
+	.globl	_Z1fv                   // -- Begin function _Z1fv
+	.p2align	2
+	.type	_Z1fv, at function
+_Z1fv:                                  // @_Z1fv
+.Lfunc_begin0:
+	.loc	0 2 0                   // /tmp/dbg.c:2:0
+	.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
+.Ltmp0:
+	//DEBUG_VALUE: f:x <- 1
+	.loc	0 4 3 prologue_end      // /tmp/dbg.c:4:3
+	sub	x0, x29, #4             // =4
+	.loc	0 3 7                   // /tmp/dbg.c:3:7
+	stur	w8, [x29, #-4]
+.Ltmp1:
+	//DEBUG_VALUE: f:x <- [DW_OP_constu 4, DW_OP_minus, DW_OP_deref] $fp
+	.loc	0 4 3                   // /tmp/dbg.c:4:3
+	bl	_Z3usePi
+.Ltmp2:
+	.loc	0 5 1                   // /tmp/dbg.c:5:1
+	ldp	x29, x30, [sp, #16]     // 16-byte Folded Reload
+	add	sp, sp, #32             // =32
+	ret
+.Ltmp3:
+.Lfunc_end0:
+	.size	_Z1fv, .Lfunc_end0-_Z1fv
+	.cfi_endproc
+                                        // -- End function
+	.section	.debug_str_offsets,"", at progbits
+	.word	40
+	.hword	5
+	.hword	0
+.Lstr_offsets_base0:
+	.section	.debug_str,"MS", at progbits,1
+.Linfo_string0:
+	.asciz	"clang version 10.0.0 (git at github.com:llvm/llvm-project.git 0a094679914ccea0f9c8f03165132172544d9799)" // string offset=0
+.Linfo_string1:
+	.asciz	"/tmp/dbg.c"            // string offset=101
+.Linfo_string2:
+	.asciz	"/code/build-llvm-cmake" // string offset=112
+.Linfo_string3:
+	.asciz	"_Z3usePi"              // string offset=135
+.Linfo_string4:
+	.asciz	"use"                   // string offset=144
+.Linfo_string5:
+	.asciz	"int"                   // string offset=148
+.Linfo_string6:
+	.asciz	"_Z1fv"                 // string offset=152
+.Linfo_string7:
+	.asciz	"f"                     // string offset=158
+.Linfo_string8:
+	.asciz	"x"                     // string offset=160
+	.section	.debug_str_offsets,"", at progbits
+	.word	.Linfo_string0
+	.word	.Linfo_string1
+	.word	.Linfo_string2
+	.word	.Linfo_string3
+	.word	.Linfo_string4
+	.word	.Linfo_string5
+	.word	.Linfo_string6
+	.word	.Linfo_string7
+	.word	.Linfo_string8
+	.section	.debug_loclists,"", at progbits
+	.word	.Ldebug_loclist_table_end0-.Ldebug_loclist_table_start0 // Length
+.Ldebug_loclist_table_start0:
+	.hword	5                       // Version
+	.byte	8                       // Address size
+	.byte	0                       // Segment selector size
+	.word	1                       // Offset entry count
+.Lloclists_table_base0:
+	.word	.Ldebug_loc0-.Lloclists_table_base0
+.Ldebug_loc0:
+	.byte	4                       // DW_LLE_offset_pair
+	.uleb128 .Ltmp0-.Lfunc_begin0   //   starting offset
+	.uleb128 .Ltmp1-.Lfunc_begin0   //   ending offset
+	.byte	3                       // Loc expr size
+	.byte	17                      // DW_OP_consts
+	.byte	1                       // 1
+	.byte	159                     // DW_OP_stack_value
+	.byte	4                       // DW_LLE_offset_pair
+	.uleb128 .Ltmp1-.Lfunc_begin0   //   starting offset
+	.uleb128 .Lfunc_end0-.Lfunc_begin0 //   ending offset
+	.byte	2                       // Loc expr size
+	.byte	141                     // DW_OP_breg29
+	.byte	124                     // -4
+	.byte	0                       // DW_LLE_end_of_list
+.Ldebug_loclist_table_end0:
+	.section	.debug_abbrev,"", at 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	114                     // DW_AT_str_offsets_base
+	.byte	23                      // DW_FORM_sec_offset
+	.byte	16                      // DW_AT_stmt_list
+	.byte	23                      // DW_FORM_sec_offset
+	.byte	27                      // DW_AT_comp_dir
+	.byte	37                      // DW_FORM_strx1
+	.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
+	.ascii	"\214\001"              // DW_AT_loclists_base
+	.byte	23                      // DW_FORM_sec_offset
+	.byte	0                       // EOM(1)
+	.byte	0                       // EOM(2)
+	.byte	2                       // Abbreviation Code
+	.byte	46                      // DW_TAG_subprogram
+	.byte	1                       // DW_CHILDREN_yes
+	.byte	110                     // DW_AT_linkage_name
+	.byte	37                      // DW_FORM_strx1
+	.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	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	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	6                       // Abbreviation Code
+	.byte	46                      // DW_TAG_subprogram
+	.byte	1                       // DW_CHILDREN_yes
+	.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	122                     // DW_AT_call_all_calls
+	.byte	25                      // DW_FORM_flag_present
+	.byte	110                     // DW_AT_linkage_name
+	.byte	37                      // DW_FORM_strx1
+	.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	63                      // DW_AT_external
+	.byte	25                      // DW_FORM_flag_present
+	.byte	0                       // EOM(1)
+	.byte	0                       // EOM(2)
+	.byte	7                       // Abbreviation Code
+	.byte	52                      // DW_TAG_variable
+	.byte	0                       // DW_CHILDREN_no
+	.byte	2                       // DW_AT_location
+	.byte	34                      // DW_FORM_loclistx
+	.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	0                       // EOM(1)
+	.byte	0                       // EOM(2)
+	.byte	8                       // Abbreviation Code
+	.byte	72                      // DW_TAG_call_site
+	.byte	0                       // DW_CHILDREN_no
+	.byte	127                     // DW_AT_call_origin
+	.byte	19                      // DW_FORM_ref4
+	.byte	125                     // DW_AT_call_return_pc
+	.byte	1                       // DW_FORM_addr
+	.byte	0                       // EOM(1)
+	.byte	0                       // EOM(2)
+	.byte	0                       // EOM(3)
+	.section	.debug_info,"", at progbits
+.Lcu_begin0:
+	.word	.Ldebug_info_end0-.Ldebug_info_start0 // Length of Unit
+.Ldebug_info_start0:
+	.hword	5                       // DWARF version number
+	.byte	1                       // DWARF Unit Type
+	.byte	8                       // Address Size (in bytes)
+	.word	.debug_abbrev           // Offset Into Abbrev. Section
+	.byte	1                       // Abbrev [1] 0xc:0x53 DW_TAG_compile_unit
+	.byte	0                       // DW_AT_producer
+	.hword	33                      // DW_AT_language
+	.byte	1                       // DW_AT_name
+	.word	.Lstr_offsets_base0     // DW_AT_str_offsets_base
+	.word	.Lline_table_start0     // DW_AT_stmt_list
+	.byte	2                       // DW_AT_comp_dir
+	.byte	0                       // DW_AT_low_pc
+	.word	.Lfunc_end0-.Lfunc_begin0 // DW_AT_high_pc
+	.word	.Laddr_table_base0      // DW_AT_addr_base
+	.word	.Lloclists_table_base0  // DW_AT_loclists_base
+	.byte	2                       // Abbrev [2] 0x27:0xb DW_TAG_subprogram
+	.byte	3                       // DW_AT_linkage_name
+	.byte	4                       // DW_AT_name
+	.byte	0                       // DW_AT_decl_file
+	.byte	1                       // DW_AT_decl_line
+                                        // DW_AT_declaration
+                                        // DW_AT_external
+	.byte	3                       // Abbrev [3] 0x2c:0x5 DW_TAG_formal_parameter
+	.word	50                      // DW_AT_type
+	.byte	0                       // End Of Children Mark
+	.byte	4                       // Abbrev [4] 0x32:0x5 DW_TAG_pointer_type
+	.word	55                      // DW_AT_type
+	.byte	5                       // Abbrev [5] 0x37:0x4 DW_TAG_base_type
+	.byte	5                       // DW_AT_name
+	.byte	5                       // DW_AT_encoding
+	.byte	4                       // DW_AT_byte_size
+	.byte	6                       // Abbrev [6] 0x3b:0x23 DW_TAG_subprogram
+	.byte	0                       // DW_AT_low_pc
+	.word	.Lfunc_end0-.Lfunc_begin0 // DW_AT_high_pc
+	.byte	1                       // DW_AT_frame_base
+	.byte	109
+                                        // DW_AT_call_all_calls
+	.byte	6                       // DW_AT_linkage_name
+	.byte	7                       // DW_AT_name
+	.byte	0                       // DW_AT_decl_file
+	.byte	2                       // DW_AT_decl_line
+                                        // DW_AT_external
+	.byte	7                       // Abbrev [7] 0x47:0x9 DW_TAG_variable
+	.byte	0                       // DW_AT_location
+	.byte	8                       // DW_AT_name
+	.byte	0                       // DW_AT_decl_file
+	.byte	3                       // DW_AT_decl_line
+	.word	55                      // DW_AT_type
+	.byte	8                       // Abbrev [8] 0x50:0xd DW_TAG_call_site
+	.word	39                      // DW_AT_call_origin
+	.xword	.Ltmp2-.Lfunc_begin0    // DW_AT_call_return_pc
+	.byte	0                       // End Of Children Mark
+	.byte	0                       // End Of Children Mark
+.Ldebug_info_end0:
+	.section	.debug_addr,"", at progbits
+	.word	.Ldebug_addr_end0-.Ldebug_addr_start0 // Length of contribution
+.Ldebug_addr_start0:
+	.hword	5                       // DWARF version number
+	.byte	8                       // Address size
+	.byte	0                       // Segment selector size
+.Laddr_table_base0:
+	.xword	.Lfunc_begin0
+.Ldebug_addr_end0:
+	.ident	"clang version 10.0.0 (git at github.com:llvm/llvm-project.git 0a094679914ccea0f9c8f03165132172544d9799)"
+	.section	".note.GNU-stack","", at progbits
+	.addrsig
+	.section	.debug_line,"", at progbits
+.Lline_table_start0:


        


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