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Google Breakpad DWARF reader: Add a handler function for DIE references.

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Add a new member function to dwarf2reader::Dwarf2Handler,
ProcessAttributeReference, for reporting attribute values that are
references to other DIEs. This handler member function always receives
an absolute offset (that is, relative to the start of the .debug_info
section, not to the start of the compilation unit), regardless of the
form the attribute uses. (Some forms are CU-relative, some are
absolute.)

a=jimblandy, r=nealsid


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@482 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
jimblandy 2010-01-12 16:53:02 +00:00
parent 0441036f9e
commit 330ca2f7c7
4 changed files with 70 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

45
src/common/dwarf/dwarf2reader.cc
View file

@ -331,24 +331,20 @@ const char* CompilationUnit::ProcessAttribute(
case DW_FORM_data1:
case DW_FORM_flag:
case DW_FORM_ref1:
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadOneByte(start));
return start + 1;
break;
case DW_FORM_ref2:
case DW_FORM_data2:
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadTwoBytes(start));
return start + 2;
break;
case DW_FORM_ref4:
case DW_FORM_data4:
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadFourBytes(start));
return start + 4;
break;
case DW_FORM_ref8:
case DW_FORM_data8:
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadEightBytes(start));
@ -362,7 +358,6 @@ const char* CompilationUnit::ProcessAttribute(
}
break;
case DW_FORM_udata:
case DW_FORM_ref_udata:
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadUnsignedLEB128(start,
&len));
@ -379,17 +374,49 @@ const char* CompilationUnit::ProcessAttribute(
reader_->ReadAddress(start));
return start + reader_->AddressSize();
break;
case DW_FORM_ref1:
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadOneByte(start)
+ offset_from_section_start_);
return start + 1;
break;
case DW_FORM_ref2:
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadTwoBytes(start)
+ offset_from_section_start_);
return start + 2;
break;
case DW_FORM_ref4:
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadFourBytes(start)
+ offset_from_section_start_);
return start + 4;
break;
case DW_FORM_ref8:
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadEightBytes(start)
+ offset_from_section_start_);
return start + 8;
break;
case DW_FORM_ref_udata:
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadUnsignedLEB128(start,
&len)
+ offset_from_section_start_);
return start + len;
break;
case DW_FORM_ref_addr:
// DWARF2 and 3 differ on whether ref_addr is address size or
// offset size.
assert(header_.version == 2 || header_.version == 3);
if (header_.version == 2) {
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadAddress(start));
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadAddress(start));
return start + reader_->AddressSize();
} else if (header_.version == 3) {
handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
reader_->ReadOffset(start));
handler_->ProcessAttributeReference(dieoffset, attr, form,
reader_->ReadOffset(start));
return start + reader_->OffsetSize();
}
break;

10
src/common/dwarf/dwarf2reader.h
View file

@ -358,6 +358,16 @@ class Dwarf2Handler {
enum DwarfForm form,
int64 data) { }
// Called when we have an attribute whose value is a reference to
// another DIE. The attribute belongs to the DIE at OFFSET from the
// beginning of the .debug_info section. Its name is ATTR, its form
// is FORM, and the offset of the DIE being referred to from the
// beginning of the .debug_info section is DATA.
virtual void ProcessAttributeReference(uint64 offset,
enum DwarfAttribute attr,
enum DwarfForm form,
uint64 data) { }
// Called when we have an attribute with a buffer of data to give to our
// handler. The attribute is for the DIE at OFFSET from the beginning of the
// .debug_info section. Its name is ATTR, its form is FORM, DATA points to

36
src/common/dwarf/functioninfo.cc
View file

@ -42,25 +42,6 @@
namespace dwarf2reader {
// Given an offset value, its form, and the base offset of the
// compilation unit containing this value, return an absolute offset
// within the .debug_info section.
uint64 GetAbsoluteOffset(uint64 offset,
enum DwarfForm form,
uint64 compilation_unit_base) {
switch (form) {
case DW_FORM_ref1:
case DW_FORM_ref2:
case DW_FORM_ref4:
case DW_FORM_ref8:
case DW_FORM_ref_udata:
return offset + compilation_unit_base;
case DW_FORM_ref_addr:
default:
return offset;
}
}
CULineInfoHandler::CULineInfoHandler(vector<SourceFileInfo>* files,
vector<string>* dirs,
LineMap* linemap):linemap_(linemap),
@ -198,6 +179,18 @@ void CUFunctionInfoHandler::ProcessAttributeUnsigned(uint64 offset,
case DW_AT_decl_file:
current_function_info_->file = files_->at(data).name;
break;
default:
break;
}
}
}
void CUFunctionInfoHandler::ProcessAttributeReference(uint64 offset,
enum DwarfAttribute attr,
enum DwarfForm form,
uint64 data) {
if (current_function_info_) {
switch (attr) {
case DW_AT_specification: {
// Some functions have a "specification" attribute
// which means they were defined elsewhere. The name
@ -205,14 +198,13 @@ void CUFunctionInfoHandler::ProcessAttributeUnsigned(uint64 offset,
// the specification DIE. Here we'll assume that
// any DIE referenced in this manner will already have
// been seen, but that's not really required by the spec.
uint64 abs_offset = GetAbsoluteOffset(data, form, current_compilation_unit_offset_);
FunctionMap::iterator iter = offset_to_funcinfo_->find(abs_offset);
FunctionMap::iterator iter = offset_to_funcinfo_->find(data);
if (iter != offset_to_funcinfo_->end()) {
current_function_info_->name = iter->second->name;
current_function_info_->mangled_name = iter->second->mangled_name;
} else {
// If you hit this, this code probably needs to be rewritten.
fprintf(stderr, "Error: DW_AT_specification was seen before the referenced DIE! (Looking for DIE at offset %08llx, in DIE at offset %08llx)\n", abs_offset, offset);
fprintf(stderr, "Error: DW_AT_specification was seen before the referenced DIE! (Looking for DIE at offset %08llx, in DIE at offset %08llx)\n", data, offset);
}
break;
}

10
src/common/dwarf/functioninfo.h
View file

@ -146,6 +146,16 @@ class CUFunctionInfoHandler: public Dwarf2Handler {
enum DwarfForm form,
uint64 data);
// Called when we have an attribute with a DIE reference to give to
// our handler. The attribute is for the DIE at OFFSET from the
// beginning of the .debug_info section, has a name of ATTR, a form of
// FORM, and the offset of the referenced DIE from the start of the
// .debug_info section is in DATA.
virtual void ProcessAttributeReference(uint64 offset,
enum DwarfAttribute attr,
enum DwarfForm form,
uint64 data);
// Called when we have an attribute with string data to give to
// our handler. The attribute is for the DIE at OFFSET from the
// beginning of the .debug_info section, has a name of ATTR, a form of