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[LLDB] - Add support for DW_FORM_implicit_const.

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LLDB does not support this DWARF5 form atm.
At least gcc emits it in some cases when doing optimization
for abbreviations.

As far I can tell, clang does not support it yet, though
the rest LLVM code already knows about it.

The patch adds the support.

Differential revision: https://reviews.llvm.org/D52689

llvm-svn: 344328
This commit is contained in:
George Rimar 2018-10-12 09:46:15 +00:00
parent 487780678f
commit 230adfa96c
10 changed files with 137 additions and 51 deletions
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41
lldb/lit/Breakpoint/Inputs/implicit_const_form_support.yaml Normal file
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@ -0,0 +1,41 @@
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...

33
lldb/lit/Breakpoint/implicit_const_form_support.test Normal file
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@ -0,0 +1,33 @@
# RUN: yaml2obj %p/Inputs/implicit_const_form_support.yaml > %ttest
# RUN: lldb-test breakpoints %ttest %s | FileCheck %s
## The intention of the test is to check that DW_FORM_implicit_const
## is supported and handled properly.
## About implicit_const_form_support.yaml:
## The following invocation and code were used to produce the binary
## which was converted to yaml and reduced:
## gcc version 8.0.1 20180319 (experimental) (GCC)
##
## g++ test.cpp -g -gdwarf-5 -o test
##
## // test.cpp
## int foo1() {
## return 0;
## }
##
## int foo2() {
## return 0;
## }
##
## int main() {
## return foo1() + foo2();
## }
b foo1
# CHECK-LABEL: b foo1
# CHECK: Address: {{.*}}foo1() at test.cpp:2:9
b foo2
# CHECK-LABEL: b foo2
# CHECK: Address: {{.*}}foo2() at test.cpp:6:9

6
lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.cpp
View File

@ -41,9 +41,13 @@ bool DWARFAbbreviationDeclaration::Extract(const DWARFDataExtractor &data,
while (data.ValidOffset(*offset_ptr)) {
dw_attr_t attr = data.GetULEB128(offset_ptr);
dw_form_t form = data.GetULEB128(offset_ptr);
DWARFFormValue::ValueType val;
if (form == DW_FORM_implicit_const)
val.value.sval = data.GetULEB128(offset_ptr);
if (attr && form)
m_attributes.push_back(DWARFAttribute(attr, form));
m_attributes.push_back(DWARFAttribute(attr, form, val));
else
break;
}

17
lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.h
View File

@ -35,20 +35,11 @@ public:
dw_form_t GetFormByIndex(uint32_t idx) const {
return m_attributes.size() > idx ? m_attributes[idx].get_form() : 0;
}
bool GetAttrAndFormByIndex(uint32_t idx, dw_attr_t &attr,
dw_form_t &form) const {
if (m_attributes.size() > idx) {
m_attributes[idx].get(attr, form);
return true;
}
attr = form = 0;
return false;
}
// idx is assumed to be valid when calling GetAttrAndFormByIndexUnchecked()
void GetAttrAndFormByIndexUnchecked(uint32_t idx, dw_attr_t &attr,
dw_form_t &form) const {
m_attributes[idx].get(attr, form);
// idx is assumed to be valid when calling GetAttrAndFormByIndex()
void GetAttrAndFormValueByIndex(uint32_t idx, dw_attr_t &attr,
DWARFFormValue &form_value) const {
m_attributes[idx].get(attr, form_value.FormRef(), form_value.ValueRef());
}
dw_form_t GetFormByIndexUnchecked(uint32_t idx) const {
return m_attributes[idx].get_form();

8
lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.cpp
View File

@ -26,10 +26,10 @@ uint32_t DWARFAttributes::FindAttributeIndex(dw_attr_t attr) const {
return UINT32_MAX;
}
void DWARFAttributes::Append(const DWARFUnit *cu,
dw_offset_t attr_die_offset, dw_attr_t attr,
dw_form_t form) {
AttributeValue attr_value = {cu, attr_die_offset, {attr, form}};
void DWARFAttributes::Append(const DWARFUnit *cu, dw_offset_t attr_die_offset,
dw_attr_t attr, dw_form_t form) {
AttributeValue attr_value = {
cu, attr_die_offset, {attr, form, DWARFFormValue::ValueType()}};
m_infos.push_back(attr_value);
}

11
lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.h
View File

@ -11,15 +11,17 @@
#define SymbolFileDWARF_DWARFAttribute_h_
#include "DWARFDefines.h"
#include "DWARFFormValue.h"
#include "llvm/ADT/SmallVector.h"
#include <vector>
class DWARFUnit;
class DWARFFormValue;
class DWARFAttribute {
public:
DWARFAttribute(dw_attr_t attr, dw_form_t form) : m_attr(attr), m_form(form) {}
DWARFAttribute(dw_attr_t attr, dw_form_t form,
DWARFFormValue::ValueType value)
: m_attr(attr), m_form(form), m_value(value) {}
void set(dw_attr_t attr, dw_form_t form) {
m_attr = attr;
@ -29,9 +31,11 @@ public:
void set_form(dw_form_t form) { m_form = form; }
dw_attr_t get_attr() const { return m_attr; }
dw_form_t get_form() const { return m_form; }
void get(dw_attr_t &attr, dw_form_t &form) const {
void get(dw_attr_t &attr, dw_form_t &form,
DWARFFormValue::ValueType &val) const {
attr = m_attr;
form = m_form;
val = m_value;
}
bool operator==(const DWARFAttribute &rhs) const {
return m_attr == rhs.m_attr && m_form == rhs.m_form;
@ -43,6 +47,7 @@ public:
protected:
dw_attr_t m_attr;
dw_form_t m_form;
DWARFFormValue::ValueType m_value;
};
class DWARFAttributes {

57
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
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@ -174,6 +174,10 @@ bool DWARFDebugInfoEntry::FastExtract(
debug_info_data.GetU32(&offset);
break;
case DW_FORM_implicit_const:
form_size = 0;
break;
default:
*offset_ptr = m_offset;
return false;
@ -233,15 +237,14 @@ bool DWARFDebugInfoEntry::Extract(SymbolFileDWARF *dwarf2Data,
// Skip all data in the .debug_info for the attributes
const uint32_t numAttributes = abbrevDecl->NumAttributes();
uint32_t i;
dw_attr_t attr;
dw_form_t form;
for (i = 0; i < numAttributes; ++i) {
abbrevDecl->GetAttrAndFormByIndexUnchecked(i, attr, form);
for (uint32_t i = 0; i < numAttributes; ++i) {
DWARFFormValue form_value(cu);
dw_attr_t attr;
abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
dw_form_t form = form_value.Form();
if (isCompileUnitTag &&
((attr == DW_AT_entry_pc) || (attr == DW_AT_low_pc))) {
DWARFFormValue form_value(cu, form);
if (form_value.ExtractValue(debug_info_data, &offset)) {
if (attr == DW_AT_low_pc || attr == DW_AT_entry_pc)
const_cast<DWARFUnit *>(cu)->SetBaseAddress(
@ -287,6 +290,7 @@ bool DWARFDebugInfoEntry::Extract(SymbolFileDWARF *dwarf2Data,
// 0 sized form
case DW_FORM_flag_present:
case DW_FORM_implicit_const:
form_size = 0;
break;
@ -417,14 +421,13 @@ bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
return false;
const uint32_t numAttributes = abbrevDecl->NumAttributes();
uint32_t i;
dw_attr_t attr;
dw_form_t form;
bool do_offset = false;
for (i = 0; i < numAttributes; ++i) {
abbrevDecl->GetAttrAndFormByIndexUnchecked(i, attr, form);
DWARFFormValue form_value(cu, form);
for (uint32_t i = 0; i < numAttributes; ++i) {
DWARFFormValue form_value(cu);
dw_attr_t attr;
abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
if (form_value.ExtractValue(debug_info_data, &offset)) {
switch (attr) {
case DW_AT_low_pc:
@ -614,14 +617,13 @@ void DWARFDebugInfoEntry::Dump(SymbolFileDWARF *dwarf2Data,
// Dump all data in the .debug_info for the attributes
const uint32_t numAttributes = abbrevDecl->NumAttributes();
uint32_t i;
dw_attr_t attr;
dw_form_t form;
for (i = 0; i < numAttributes; ++i) {
abbrevDecl->GetAttrAndFormByIndexUnchecked(i, attr, form);
for (uint32_t i = 0; i < numAttributes; ++i) {
DWARFFormValue form_value(cu);
dw_attr_t attr;
abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
DumpAttribute(dwarf2Data, cu, debug_info_data, &offset, s, attr,
form);
form_value);
}
const DWARFDebugInfoEntry *child = GetFirstChild();
@ -671,23 +673,21 @@ void DWARFDebugInfoEntry::DumpLocation(SymbolFileDWARF *dwarf2Data,
void DWARFDebugInfoEntry::DumpAttribute(
SymbolFileDWARF *dwarf2Data, const DWARFUnit *cu,
const DWARFDataExtractor &debug_info_data, lldb::offset_t *offset_ptr,
Stream &s, dw_attr_t attr, dw_form_t form) {
Stream &s, dw_attr_t attr, DWARFFormValue &form_value) {
bool show_form = s.GetFlags().Test(DWARFDebugInfo::eDumpFlag_ShowForm);
s.Printf(" ");
s.Indent(DW_AT_value_to_name(attr));
if (show_form) {
s.Printf("[%s", DW_FORM_value_to_name(form));
s.Printf("[%s", DW_FORM_value_to_name(form_value.Form()));
}
DWARFFormValue form_value(cu, form);
if (!form_value.ExtractValue(debug_info_data, offset_ptr))
return;
if (show_form) {
if (form == DW_FORM_indirect) {
if (form_value.Form() == DW_FORM_indirect) {
s.Printf(" [%s]", DW_FORM_value_to_name(form_value.Form()));
}
@ -794,11 +794,11 @@ size_t DWARFDebugInfoEntry::GetAttributes(
cu->GetAddressByteSize(), cu->IsDWARF64());
const uint32_t num_attributes = abbrevDecl->NumAttributes();
uint32_t i;
dw_attr_t attr;
dw_form_t form;
for (i = 0; i < num_attributes; ++i) {
abbrevDecl->GetAttrAndFormByIndexUnchecked(i, attr, form);
for (uint32_t i = 0; i < num_attributes; ++i) {
DWARFFormValue form_value(cu);
dw_attr_t attr;
abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
const dw_form_t form = form_value.Form();
// If we are tracking down DW_AT_specification or DW_AT_abstract_origin
// attributes, the depth will be non-zero. We need to omit certain
@ -819,7 +819,6 @@ size_t DWARFDebugInfoEntry::GetAttributes(
}
if ((attr == DW_AT_specification) || (attr == DW_AT_abstract_origin)) {
DWARFFormValue form_value(cu, form);
if (form_value.ExtractValue(debug_info_data, &offset)) {
dw_offset_t die_offset = form_value.Reference();
DWARFDIE spec_die =

2
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
View File

@ -178,7 +178,7 @@ public:
DumpAttribute(SymbolFileDWARF *dwarf2Data, const DWARFUnit *cu,
const lldb_private::DWARFDataExtractor &debug_info_data,
lldb::offset_t *offset_ptr, lldb_private::Stream &s,
dw_attr_t attr, dw_form_t form);
dw_attr_t attr, DWARFFormValue &form_value);
// This one dumps the comp unit name, objfile name and die offset for this die
// so the stream S.
void DumpLocation(SymbolFileDWARF *dwarf2Data, DWARFUnit *cu,

8
lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp
View File

@ -154,6 +154,9 @@ DWARFFormValue::GetFixedFormSizesForAddressSize(uint8_t addr_size,
DWARFFormValue::DWARFFormValue() : m_cu(NULL), m_form(0), m_value() {}
DWARFFormValue::DWARFFormValue(const DWARFUnit *cu)
: m_cu(cu), m_form(0), m_value() {}
DWARFFormValue::DWARFFormValue(const DWARFUnit *cu, dw_form_t form)
: m_cu(cu), m_form(form), m_value() {}
@ -165,6 +168,9 @@ void DWARFFormValue::Clear() {
bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data,
lldb::offset_t *offset_ptr) {
if (m_form == DW_FORM_implicit_const)
return true;
bool indirect = false;
bool is_block = false;
m_value.data = NULL;
@ -366,6 +372,7 @@ bool DWARFFormValue::SkipValue(dw_form_t form,
// 0 bytes values (implied from DW_FORM)
case DW_FORM_flag_present:
case DW_FORM_implicit_const:
return true;
// 1 byte values
@ -822,6 +829,7 @@ bool DWARFFormValue::FormIsSupported(dw_form_t form) {
case DW_FORM_ref_sig8:
case DW_FORM_GNU_str_index:
case DW_FORM_GNU_addr_index:
case DW_FORM_implicit_const:
return true;
default:
break;

5
lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
View File

@ -56,12 +56,17 @@ public:
};
DWARFFormValue();
DWARFFormValue(const DWARFUnit *cu);
DWARFFormValue(const DWARFUnit *cu, dw_form_t form);
const DWARFUnit *GetCompileUnit() const { return m_cu; }
void SetCompileUnit(const DWARFUnit *cu) { m_cu = cu; }
dw_form_t Form() const { return m_form; }
dw_form_t& FormRef() { return m_form; }
void SetForm(dw_form_t form) { m_form = form; }
const ValueType &Value() const { return m_value; }
ValueType &ValueRef() { return m_value; }
void SetValue(const ValueType &val) { m_value = val; }
void Dump(lldb_private::Stream &s) const;
bool ExtractValue(const lldb_private::DWARFDataExtractor &data,
lldb::offset_t *offset_ptr);