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DWARFExpression: Fix/add support for (v4) debug_loc base address selection entries 

The DWARFExpression is parsing the location lists in about five places.
Of those, only one actually had proper support for base address
selection entries.

Since r374600, llvm has started to produce location expressions with
base address selection entries more aggresively, which caused some tests
to fail.

This patch adds support for these entries to the places which had it
missing, fixing the failing tests. It also adds a targeted test for the
two of the three fixes, which should continue testing this functionality
even if the llvm output changes. I am not aware of a way to write a
targeted test for the third fix (DWARFExpression::Evaluate).

llvm-svn: 374769
This commit is contained in:
Pavel Labath 2019-10-14 12:49:06 +00:00
parent 1a21f98ac3
commit 5a8db84964
2 changed files with 47 additions and 12 deletions
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18
lldb/source/Expression/DWARFExpression.cpp
View File

@ -636,6 +636,11 @@ bool DWARFExpression::LocationListContainsAddress(
if (lo_pc == 0 && hi_pc == 0)
break;
if ((m_data.GetAddressByteSize() == 4 && (lo_pc == UINT32_MAX)) ||
(m_data.GetAddressByteSize() == 8 && (lo_pc == UINT64_MAX))) {
loclist_base_addr = hi_pc + m_loclist_slide;
continue;
}
lo_pc += loclist_base_addr - m_loclist_slide;
hi_pc += loclist_base_addr - m_loclist_slide;
@ -671,6 +676,12 @@ bool DWARFExpression::GetLocation(addr_t base_addr, addr_t pc,
if (lo_pc == 0 && hi_pc == 0)
break;
if ((m_data.GetAddressByteSize() == 4 && (lo_pc == UINT32_MAX)) ||
(m_data.GetAddressByteSize() == 8 && (lo_pc == UINT64_MAX))) {
curr_base_addr = hi_pc + m_loclist_slide;
continue;
}
lo_pc += curr_base_addr - m_loclist_slide;
hi_pc += curr_base_addr - m_loclist_slide;
@ -967,6 +978,13 @@ bool DWARFExpression::Evaluate(ExecutionContext *exe_ctx,
if (lo_pc == 0 && hi_pc == 0)
break;
if ((m_data.GetAddressByteSize() == 4 &&
(lo_pc == UINT32_MAX)) ||
(m_data.GetAddressByteSize() == 8 &&
(lo_pc == UINT64_MAX))) {
curr_loclist_base_load_addr = hi_pc + m_loclist_slide;
continue;
}
lo_pc += curr_loclist_base_load_addr - m_loclist_slide;
hi_pc += curr_loclist_base_load_addr - m_loclist_slide;

41
lldb/test/Shell/SymbolFile/DWARF/debug_loc.s
View File

@ -17,14 +17,22 @@
# 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,
.type f,@function
f: # @f
.Lfunc_begin0:
movl %edi, %eax
nop
.Ltmp0:
retq
nop
.Ltmp1:
nop
.Ltmp2:
nop
.Ltmp3:
nop
.Ltmp4:
nop
.Lfunc_end0:
.size f, .Lfunc_end0-f
@ -35,12 +43,6 @@ f: # @f
.asciz "f"
.Linfo_string4:
.asciz "int"
.Lx0:
.asciz "x0"
.Lx1:
.asciz "x1"
.Lx2:
.asciz "x2"
.section .debug_loc,"",@progbits
.Ldebug_loc0:
@ -54,6 +56,17 @@ f: # @f
.byte 80 # super-register DW_OP_reg0
.quad 0
.quad 0
.Ldebug_loc3:
.quad -1 # Select base address
.quad .Ltmp1
.quad .Ltmp1-.Ltmp1
.quad .Ltmp2-.Ltmp1
.short 1 # Loc expr size
.byte 81 # super-register DW_OP_reg1
.quad 0
.quad 0
.Ldebug_loc2:
.quad .Lfunc_begin0-.Lfunc_begin0
.quad .Lfunc_end0-.Lfunc_begin0
@ -88,7 +101,7 @@ f: # @f
.byte 2 # DW_AT_location
.byte 23 # DW_FORM_sec_offset
.byte 3 # DW_AT_name
.byte 14 # DW_FORM_strp
.byte 8 # DW_FORM_string
.byte 73 # DW_AT_type
.byte 19 # DW_FORM_ref4
.byte 0 # EOM(1)
@ -123,15 +136,19 @@ f: # @f
.long .Lint # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long .Ldebug_loc0 # DW_AT_location
.long .Lx0 # DW_AT_name
.asciz "x0" # DW_AT_name
.long .Lint-.Lcu_begin0 # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long 0xdeadbeef # DW_AT_location
.long .Lx1 # DW_AT_name
.asciz "x1" # DW_AT_name
.long .Lint-.Lcu_begin0 # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long .Ldebug_loc2 # DW_AT_location
.long .Lx2 # DW_AT_name
.asciz "x2" # DW_AT_name
.long .Lint-.Lcu_begin0 # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long .Ldebug_loc3 # DW_AT_location
.asciz "x3" # DW_AT_name
.long .Lint-.Lcu_begin0 # DW_AT_type
.byte 0 # End Of Children Mark
.Lint: