[lldb/DWARF] Switch to llvm location list parser

Summary:
This patch deletes the lldb location list parser and teaches the
DWARFExpression class to use the parser in llvm instead. I have
centralized all the places doing the parsing into a single
GetLocationExpression function.

In theory the the actual location list parsing should be covered by llvm
tests, and this glue code by our existing location list tests, but since
we don't have that many location list tests, I've tried to extend the
coverage a bit by adding some explicit dwarf5 loclist handling and a
test of the dumping code.

For DWARF4 location lists this should be NFC (modulo small differences
in error handling which should only show up on invalid inputs). In case
of DWARF5, this fixes various missing bits of functionality, most
notably, the lack of support for DW_LLE_offset_pair.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: lldb-commits, dblaikie

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71003

1 files changed, 111 insertions, 24 deletions

diff --git a/lldb/test/Shell/SymbolFile/DWARF/debug_loc.s b/lldb/test/Shell/SymbolFile/DWARF/debug_loc.s
index bc9c44db4c0..0892b5f0d2d 100644
--- a/lldb/test/Shell/SymbolFile/DWARF/debug_loc.s
+++ b/lldb/test/Shell/SymbolFile/DWARF/debug_loc.s
@@ -1,24 +1,82 @@
-# Test debug_loc parsing, including the cases of invalid input. The exact
+# Test location list handling, including the cases of invalid input. The exact
 # behavior in the invalid cases is not particularly important, but it should be
 # "reasonable".
 
 # REQUIRES: x86
 
-# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t
-# RUN: %lldb %t -o "image lookup -v -a 0" -o "image lookup -v -a 2" -o exit \
-# RUN:   | FileCheck %s
+# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s --defsym LOC=0 > %t
+# RUN: %lldb %t -o "image lookup -v -a 0" -o "image lookup -v -a 2" \
+# RUN:   -o "image dump symfile" -o exit | FileCheck %s
+
+# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s --defsym LOCLISTS=0 > %t
+# RUN: %lldb %t -o "image lookup -v -a 0" -o "image lookup -v -a 2" \
+# RUN:   -o "image dump symfile" -o exit | FileCheck %s --check-prefix=CHECK --check-prefix=LOCLISTS
 
 # CHECK-LABEL: image lookup -v -a 0
 # CHECK: Variable: {{.*}}, name = "x0", type = "int", location = DW_OP_reg5 RDI,
 # CHECK: Variable: {{.*}}, name = "x1", type = "int", location = ,
-# CHECK: Variable: {{.*}}, name = "x2", type = "int", location = ,
 
 # CHECK-LABEL: image lookup -v -a 2
 # CHECK: Variable: {{.*}}, name = "x0", type = "int", location = DW_OP_reg0 RAX,
 # CHECK: Variable: {{.*}}, name = "x1", type = "int", location = ,
-# CHECK: Variable: {{.*}}, name = "x2", type = "int", location = ,
 # CHECK: Variable: {{.*}}, name = "x3", type = "int", location = DW_OP_reg1 RDX,
 
+# CHECK-LABEL: image dump symfile
+# CHECK: CompileUnit{0x00000000}
+# CHECK:   Function{
+# CHECK:     Variable{{.*}}, name = "x0", {{.*}}, scope = parameter, location =
+# CHECK-NEXT:  [0x0000000000000000, 0x0000000000000001): DW_OP_reg5 RDI
+# CHECK-NEXT:  [0x0000000000000001, 0x0000000000000006): DW_OP_reg0 RAX
+# CHECK:     Variable{{.*}}, name = "x1", {{.*}}, scope = parameter
+# CHECK:     Variable{{.*}}, name = "x2", {{.*}}, scope = parameter, location =
+# CHECK-NEXT:  error: unexpected end of data
+# CHECK:     Variable{{.*}}, name = "x3", {{.*}}, scope = parameter, location =
+# CHECK-NEXT:  [0x0000000000000002, 0x0000000000000003): DW_OP_reg1 RDX
+# LOCLISTS:  Variable{{.*}}, name = "x4", {{.*}}, scope = parameter, location =
+# LOCLISTS-NEXT: DW_LLE_startx_length   (0x000000000000dead, 0x0000000000000001): DW_OP_reg2 RCX
+
+.ifdef LOC
+.macro OFFSET_PAIR lo hi
+        .quad \lo
+        .quad \hi
+.endm
+
+.macro BASE_ADDRESS base
+        .quad -1
+        .quad \base
+.endm
+
+.macro EXPR_SIZE sz
+        .short \sz
+.endm
+
+.macro END_OF_LIST
+        .quad 0
+        .quad 0
+.endm
+.endif
+
+.ifdef LOCLISTS
+.macro OFFSET_PAIR lo hi
+        .byte   4                       # DW_LLE_offset_pair
+        .uleb128 \lo
+        .uleb128 \hi
+.endm
+
+.macro BASE_ADDRESS base
+        .byte   6                       # DW_LLE_base_address
+        .quad \base
+.endm
+
+.macro EXPR_SIZE sz
+        .uleb128 \sz
+.endm
+
+.macro END_OF_LIST
+        .byte   0                       # DW_LLE_end_of_list
+.endm
+.endif
+
         .type   f,@function
 f:                                      # @f
 .Lfunc_begin0:
@@ -44,33 +102,48 @@ f:                                      # @f
 .Linfo_string4:
         .asciz  "int"
 
+.ifdef LOC
         .section        .debug_loc,"",@progbits
+.endif
+.ifdef LOCLISTS
+        .section        .debug_loclists,"",@progbits
+        .long   .Ldebug_loclist_table_end0-.Ldebug_loclist_table_start0 # Length
+.Ldebug_loclist_table_start0:
+        .short  5                       # Version
+        .byte   8                       # Address size
+        .byte   0                       # Segment selector size
+        .long   0                       # Offset entry count
+.endif
 .Ldebug_loc0:
-        .quad   .Lfunc_begin0-.Lfunc_begin0
-        .quad   .Ltmp0-.Lfunc_begin0
-        .short  1                       # Loc expr size
+        OFFSET_PAIR .Lfunc_begin0-.Lfunc_begin0, .Ltmp0-.Lfunc_begin0
+        EXPR_SIZE 1
         .byte   85                      # super-register DW_OP_reg5
-        .quad   .Ltmp0-.Lfunc_begin0
-        .quad   .Lfunc_end0-.Lfunc_begin0
-        .short  1                       # Loc expr size
+        OFFSET_PAIR   .Ltmp0-.Lfunc_begin0, .Lfunc_end0-.Lfunc_begin0
+        EXPR_SIZE 1
         .byte   80                      # super-register DW_OP_reg0
-        .quad   0
-        .quad   0
+        END_OF_LIST
 
 .Ldebug_loc3:
-        .quad   -1                      # Select base address
-        .quad   .Ltmp1
-        .quad   .Ltmp1-.Ltmp1
-        .quad   .Ltmp2-.Ltmp1
-        .short  1                       # Loc expr size
+        BASE_ADDRESS .Ltmp1
+        OFFSET_PAIR .Ltmp1-.Ltmp1, .Ltmp2-.Ltmp1
+        EXPR_SIZE 1
         .byte   81                      # super-register DW_OP_reg1
-        .quad   0
-        .quad   0
+        END_OF_LIST
+
+.ifdef LOCLISTS
+.Ldebug_loc4:
+        .byte   3                       # DW_LLE_startx_length
+        .uleb128 0xdead
+        .uleb128 1
+        EXPR_SIZE 1
+        .byte   82                      # super-register DW_OP_reg2
+        END_OF_LIST
+.endif
 
 .Ldebug_loc2:
-        .quad   .Lfunc_begin0-.Lfunc_begin0
-        .quad   .Lfunc_end0-.Lfunc_begin0
-        .short  0xdead                  # Loc expr size
+        OFFSET_PAIR .Lfunc_begin0-.Lfunc_begin0, .Lfunc_end0-.Lfunc_begin0
+        EXPR_SIZE  0xdead
+.Ldebug_loclist_table_end0:
 
         .section        .debug_abbrev,"",@progbits
         .byte   1                       # Abbreviation Code
@@ -123,9 +196,17 @@ f:                                      # @f
 .Lcu_begin0:
         .long   .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
 .Ldebug_info_start0:
+.ifdef LOC
         .short  4                       # DWARF version number
         .long   .debug_abbrev           # Offset Into Abbrev. Section
         .byte   8                       # Address Size (in bytes)
+.endif
+.ifdef LOCLISTS
+        .short  5                       # DWARF version number
+        .byte   1                       # DWARF Unit Type
+        .byte   8                       # Address Size (in bytes)
+        .long   .debug_abbrev           # Offset Into Abbrev. Section
+.endif
         .byte   1                       # Abbrev [1] 0xb:0x50 DW_TAG_compile_unit
         .long   .Linfo_string0          # DW_AT_producer
         .short  12                      # DW_AT_language
@@ -150,6 +231,12 @@ f:                                      # @f
         .long   .Ldebug_loc3            # DW_AT_location
         .asciz  "x3"                    # DW_AT_name
         .long   .Lint-.Lcu_begin0       # DW_AT_type
+.ifdef LOCLISTS
+        .byte   3                       # Abbrev [3] DW_TAG_formal_parameter
+        .long   .Ldebug_loc4            # DW_AT_location
+        .asciz  "x4"                    # DW_AT_name
+        .long   .Lint-.Lcu_begin0       # DW_AT_type
+.endif
         .byte   0                       # End Of Children Mark
 .Lint:
         .byte   4                       # Abbrev [4] 0x53:0x7 DW_TAG_base_type