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Added the ability for Target::ReadMemory to prefer to read from the file 

cache even when a valid process exists. Previously, Target::ReadMemory would
read from the process if there was a valid one and then fallback to the
object file cache.

llvm-svn: 122989
This commit is contained in:
Greg Clayton 2011-01-07 01:57:07 +00:00
parent 1c926b78fe
commit db59823068
5 changed files with 74 additions and 19 deletions
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19
lldb/include/lldb/Target/Target.h
View File

@ -400,13 +400,28 @@ public:
bool
GetTargetTriple (ConstString &target_triple);
size_t
ReadMemoryFromFileCache (const Address& addr,
void *dst,
size_t dst_len,
Error &error);
// Reading memory through the target allows us to skip going to the process
// for reading memory if possible and it allows us to try and read from
// any constant sections in our object files on disk. If you always want
// live program memory, read straight from the process. If you possibly
// want to read from const sections in object files, read from the target.
// This version of ReadMemory will try and read memory from the process
// if the process is alive. The order is:
// 1 - if (prefer_file_cache == true) then read from object file cache
// 2 - if there is a valid process, try and read from its memory
// 3 - if (prefer_file_cache == false) then read from object file cache
size_t
ReadMemory (const Address& addr,
bool prefer_file_cache,
void *dst,
size_t dst_len,
Error &error);
SectionLoadList&
GetSectionLoadList()

3
lldb/source/Core/Address.cpp
View File

@ -68,7 +68,8 @@ ReadBytes (ExecutionContextScope *exe_scope, const Address &address, void *dst,
if (target)
{
Error error;
return target->ReadMemory (address, dst, dst_len, error);
bool prefer_file_cache = false;
return target->ReadMemory (address, prefer_file_cache, dst, dst_len, error);
}
return 0;
}

3
lldb/source/Core/Disassembler.cpp
View File

@ -422,7 +422,8 @@ Disassembler::ParseInstructions
DataBufferSP data_sp(heap_buffer);
Error error;
const size_t bytes_read = target->ReadMemory (range.GetBaseAddress(), heap_buffer->GetBytes(), heap_buffer->GetByteSize(), error);
bool prefer_file_cache = true;
const size_t bytes_read = target->ReadMemory (range.GetBaseAddress(), prefer_file_cache, heap_buffer->GetBytes(), heap_buffer->GetByteSize(), error);
if (bytes_read > 0)
{

14
lldb/source/Plugins/Process/Utility/UnwindAssemblyProfiler-x86.cpp
View File

@ -470,7 +470,8 @@ read_byte_for_edis (uint8_t *buf, uint64_t offset_address, void *arg)
uint8_t onebyte_buf[1];
Error error;
if (target->ReadMemory (read_addr, onebyte_buf, 1, error) != -1)
const bool prefer_file_cache = true;
if (target->ReadMemory (read_addr, prefer_file_cache, onebyte_buf, 1, error) != -1)
{
*buf = onebyte_buf[0];
return 0;
@ -550,6 +551,7 @@ AssemblyParse_x86::get_non_call_site_unwind_plan (UnwindPlan &unwind_plan)
row.SetRegisterInfo (m_lldb_ip_regnum, initial_regloc);
unwind_plan.AppendRow (row);
const bool prefer_file_cache = true;
while (m_func_bounds.ContainsFileAddress (m_cur_insn) && non_prologue_insn_count < 10)
{
@ -562,7 +564,7 @@ AssemblyParse_x86::get_non_call_site_unwind_plan (UnwindPlan &unwind_plan)
// An unrecognized/junk instruction
break;
}
if (m_target.ReadMemory (m_cur_insn, m_cur_insn_bytes, insn_len, error) == -1)
if (m_target.ReadMemory (m_cur_insn, prefer_file_cache, m_cur_insn_bytes, insn_len, error) == -1)
{
// Error reading the instruction out of the file, stop scanning
break;
@ -672,7 +674,7 @@ loopnext:
Address last_insn (m_func_bounds.GetBaseAddress());
last_insn.SetOffset (last_insn.GetOffset() + m_func_bounds.GetByteSize() - 1);
uint8_t bytebuf[1];
if (m_target.ReadMemory (last_insn, bytebuf, 1, error) != -1)
if (m_target.ReadMemory (last_insn, prefer_file_cache, bytebuf, 1, error) != -1)
{
if (bytebuf[0] == 0xc3) // ret aka retq
{
@ -723,7 +725,8 @@ AssemblyParse_x86::get_fast_unwind_plan (AddressRange& func, UnwindPlan &unwind_
uint8_t bytebuf[4];
Error error;
if (m_target.ReadMemory (func.GetBaseAddress(), bytebuf, sizeof (bytebuf), error) == -1)
const bool prefer_file_cache = true;
if (m_target.ReadMemory (func.GetBaseAddress(), prefer_file_cache, bytebuf, sizeof (bytebuf), error) == -1)
return false;
uint8_t i386_prologue[] = {0x55, 0x89, 0xe5};
@ -781,6 +784,7 @@ AssemblyParse_x86::find_first_non_prologue_insn (Address &address)
return false;
}
const bool prefer_file_cache = true;
while (m_func_bounds.ContainsFileAddress (m_cur_insn))
{
Error error;
@ -790,7 +794,7 @@ AssemblyParse_x86::find_first_non_prologue_insn (Address &address)
// An error parsing the instruction, i.e. probably data/garbage - stop scanning
break;
}
if (m_target.ReadMemory (m_cur_insn, m_cur_insn_bytes, insn_len, error) == -1)
if (m_target.ReadMemory (m_cur_insn, prefer_file_cache, m_cur_insn_bytes, insn_len, error) == -1)
{
// Error reading the instruction out of the file, stop scanning
break;

54
lldb/source/Target/Target.cpp
View File

@ -589,12 +589,43 @@ Target::ModulesDidUnload (ModuleList &module_list)
}
size_t
Target::ReadMemory (const Address& addr, void *dst, size_t dst_len, Error &error)
Target::ReadMemoryFromFileCache (const Address& addr, void *dst, size_t dst_len, Error &error)
{
const Section *section = addr.GetSection();
if (section && section->GetModule())
{
ObjectFile *objfile = section->GetModule()->GetObjectFile();
if (objfile)
{
size_t bytes_read = section->ReadSectionDataFromObjectFile (objfile,
addr.GetOffset(),
dst,
dst_len);
if (bytes_read > 0)
return bytes_read;
else
error.SetErrorStringWithFormat("error reading data from section %s", section->GetName().GetCString());
}
else
{
error.SetErrorString("address isn't from a object file");
}
}
else
{
error.SetErrorString("address doesn't contain a section that points to a section in a object file");
}
return 0;
}
size_t
Target::ReadMemory (const Address& addr, bool prefer_file_cache, void *dst, size_t dst_len, Error &error)
{
error.Clear();
bool process_is_valid = m_process_sp && m_process_sp->IsAlive();
size_t bytes_read = 0;
Address resolved_addr(addr);
if (!resolved_addr.IsSectionOffset())
{
@ -608,6 +639,12 @@ Target::ReadMemory (const Address& addr, void *dst, size_t dst_len, Error &error
}
}
if (prefer_file_cache)
{
bytes_read = ReadMemoryFromFileCache (resolved_addr, dst, dst_len, error);
if (bytes_read > 0)
return bytes_read;
}
if (process_is_valid)
{
@ -623,7 +660,7 @@ Target::ReadMemory (const Address& addr, void *dst, size_t dst_len, Error &error
}
else
{
size_t bytes_read = m_process_sp->ReadMemory(load_addr, dst, dst_len, error);
bytes_read = m_process_sp->ReadMemory(load_addr, dst, dst_len, error);
if (bytes_read != dst_len)
{
if (error.Success())
@ -646,14 +683,11 @@ Target::ReadMemory (const Address& addr, void *dst, size_t dst_len, Error &error
}
}
const Section *section = resolved_addr.GetSection();
if (section && section->GetModule())
if (!prefer_file_cache)
{
ObjectFile *objfile = section->GetModule()->GetObjectFile();
return section->ReadSectionDataFromObjectFile (objfile,
resolved_addr.GetOffset(),
dst,
dst_len);
// If we didn't already try and read from the object file cache, then
// try it after failing to read from the process.
return ReadMemoryFromFileCache (resolved_addr, dst, dst_len, error);
}
return 0;
}