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Patch from Andrew Kaylor for linux:

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The attached patch adds support for debugging 32-bit processes when running a 64-bit lldb on an x86_64 Linux system.
 
Making this work required two basic changes:
 
1)      Getting lldb to report that it could debug 32-bit processes
2)      Changing an assumption about how ptrace works when debugging cross-platform
 
For the first change, I took a conservative approach and only enabled this for x86_64 Linux platforms.  It may be that the change I made in Host.cpp could be extended to other 64-bit Linux platforms, but I'm not familiar enough with the other platforms to know for sure.
 
For the second change, the Linux ProcessMonitor class was assuming that ptrace(PTRACE_[PEEK|POKE]DATA...) would read/write a "word" based on the child process word size.  However, the ptrace documentation says that the "word" size read or written is "determined by the OS variant."  I verified experimentally that when ptracing a 32-bit child from a 64-bit parent a 64-bit word is read or written.

llvm-svn: 163398
This commit is contained in:
Greg Clayton
2012-09-07 17:49:29 +00:00
parent a5a00e830a
commit 542e407581
3 changed files with 43 additions and 26 deletions
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6
lldb/source/Host/common/Host.cpp
View File

@@ -339,6 +339,12 @@ Host::GetArchitecture (SystemDefaultArchitecture arch_kind)
break;
case llvm::Triple::x86_64:
g_host_arch_64.SetTriple(triple);
g_supports_64 = true;
g_host_arch_32.SetTriple(triple.get32BitArchVariant());
g_supports_32 = true;
break;
case llvm::Triple::sparcv9:
case llvm::Triple::ppc64:
case llvm::Triple::cellspu:

11
lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp
View File

@@ -312,6 +312,17 @@ PlatformLinux::GetSupportedArchitectureAtIndex (uint32_t idx, ArchSpec &arch)
arch = Host::GetArchitecture (Host::eSystemDefaultArchitecture);
return arch.IsValid();
}
else if (idx == 1)
{
// If the default host architecture is 64-bit, look for a 32-bit variant
ArchSpec hostArch
= Host::GetArchitecture(Host::eSystemDefaultArchitecture);
if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit())
{
arch = Host::GetArchitecture (Host::eSystemDefaultArchitecture32);
return arch.IsValid();
}
}
return false;
}

52
lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
View File

@@ -77,19 +77,19 @@ static void PtraceDisplayBytes(__ptrace_request &req, void *data)
verbose_log->Printf("PTRACE_POKETEXT %s", buf.GetData());
break;
}
case PTRACE_POKEDATA:
case PTRACE_POKEDATA:
{
DisplayBytes(buf, &data, 8);
verbose_log->Printf("PTRACE_POKEDATA %s", buf.GetData());
break;
}
case PTRACE_POKEUSER:
case PTRACE_POKEUSER:
{
DisplayBytes(buf, &data, 8);
verbose_log->Printf("PTRACE_POKEUSER %s", buf.GetData());
break;
}
case PTRACE_SETREGS:
case PTRACE_SETREGS:
{
DisplayBytes(buf, data, sizeof(user_regs_struct));
verbose_log->Printf("PTRACE_SETREGS %s", buf.GetData());
@@ -101,7 +101,7 @@ static void PtraceDisplayBytes(__ptrace_request &req, void *data)
verbose_log->Printf("PTRACE_SETFPREGS %s", buf.GetData());
break;
}
case PTRACE_SETSIGINFO:
case PTRACE_SETSIGINFO:
{
DisplayBytes(buf, data, sizeof(siginfo_t));
verbose_log->Printf("PTRACE_SETSIGINFO %s", buf.GetData());
@@ -126,7 +126,7 @@ PtraceWrapper(__ptrace_request req, pid_t pid, void *addr, void *data,
if (log)
log->Printf("ptrace(%s, %u, %p, %p) called from file %s line %d",
reqName, pid, addr, data, file, line);
PtraceDisplayBytes(req, data);
errno = 0;
@@ -163,9 +163,11 @@ PtraceWrapper(__ptrace_request req, pid_t pid, void *addr, void *data,
// functions without needed to go thru the thread funnel.
static size_t
DoReadMemory(lldb::pid_t pid, unsigned word_size,
DoReadMemory(lldb::pid_t pid,
lldb::addr_t vm_addr, void *buf, size_t size, Error &error)
{
// ptrace word size is determined by the host, not the child
static const unsigned word_size = sizeof(void*);
unsigned char *dst = static_cast<unsigned char*>(buf);
size_t bytes_read;
size_t remainder;
@@ -179,7 +181,6 @@ DoReadMemory(lldb::pid_t pid, unsigned word_size,
pid, word_size, (void*)vm_addr, buf, size);
assert(sizeof(data) >= word_size);
assert(sizeof(void*) == word_size);
for (bytes_read = 0; bytes_read < size; bytes_read += remainder)
{
errno = 0;
@@ -218,9 +219,11 @@ DoReadMemory(lldb::pid_t pid, unsigned word_size,
}
static size_t
DoWriteMemory(lldb::pid_t pid, unsigned word_size,
DoWriteMemory(lldb::pid_t pid,
lldb::addr_t vm_addr, const void *buf, size_t size, Error &error)
{
// ptrace word size is determined by the host, not the child
static const unsigned word_size = sizeof(void*);
const unsigned char *src = static_cast<const unsigned char*>(buf);
size_t bytes_written = 0;
size_t remainder;
@@ -232,7 +235,6 @@ DoWriteMemory(lldb::pid_t pid, unsigned word_size,
log->Printf ("ProcessMonitor::%s(%d, %d, %p, %p, %d, _)", __FUNCTION__,
pid, word_size, (void*)vm_addr, buf, size);
assert(sizeof(void*) == word_size);
for (bytes_written = 0; bytes_written < size; bytes_written += remainder)
{
remainder = size - bytes_written;
@@ -263,7 +265,7 @@ DoWriteMemory(lldb::pid_t pid, unsigned word_size,
else
{
unsigned char buff[8];
if (DoReadMemory(pid, word_size, vm_addr,
if (DoReadMemory(pid, vm_addr,
buff, word_size, error) != word_size)
{
if (log)
@@ -273,7 +275,7 @@ DoWriteMemory(lldb::pid_t pid, unsigned word_size,
memcpy(buff, src, remainder);
if (DoWriteMemory(pid, word_size, vm_addr,
if (DoWriteMemory(pid, vm_addr,
buff, word_size, error) != word_size)
{
if (log)
@@ -361,10 +363,9 @@ private:
void
ReadOperation::Execute(ProcessMonitor *monitor)
{
const unsigned word_size = monitor->GetProcess().GetAddressByteSize();
lldb::pid_t pid = monitor->GetPID();
m_result = DoReadMemory(pid, word_size, m_addr, m_buff, m_size, m_error);
m_result = DoReadMemory(pid, m_addr, m_buff, m_size, m_error);
}
//------------------------------------------------------------------------------
@@ -392,10 +393,9 @@ private:
void
WriteOperation::Execute(ProcessMonitor *monitor)
{
const unsigned word_size = monitor->GetProcess().GetAddressByteSize();
lldb::pid_t pid = monitor->GetPID();
m_result = DoWriteMemory(pid, word_size, m_addr, m_buff, m_size, m_error);
m_result = DoWriteMemory(pid, m_addr, m_buff, m_size, m_error);
}
@@ -744,7 +744,7 @@ DetachOperation::Execute(ProcessMonitor *monitor)
if (ptrace(PT_DETACH, pid, NULL, 0) < 0)
m_error.SetErrorToErrno();
}
ProcessMonitor::OperationArgs::OperationArgs(ProcessMonitor *monitor)
@@ -1060,22 +1060,22 @@ ProcessMonitor::Launch(LaunchArgs *args)
args->m_error.SetErrorToGenericError();
switch (WEXITSTATUS(status))
{
case ePtraceFailed:
case ePtraceFailed:
args->m_error.SetErrorString("Child ptrace failed.");
break;
case eDupStdinFailed:
case eDupStdinFailed:
args->m_error.SetErrorString("Child open stdin failed.");
break;
case eDupStdoutFailed:
case eDupStdoutFailed:
args->m_error.SetErrorString("Child open stdout failed.");
break;
case eDupStderrFailed:
case eDupStderrFailed:
args->m_error.SetErrorString("Child open stderr failed.");
break;
case eExecFailed:
case eExecFailed:
args->m_error.SetErrorString("Child exec failed.");
break;
default:
default:
args->m_error.SetErrorString("Child returned unknown exit status.");
break;
}
@@ -1228,7 +1228,7 @@ ProcessMonitor::MonitorCallback(void *callback_baton,
case SIGTRAP:
message = MonitorSIGTRAP(monitor, &info, pid);
break;
default:
message = MonitorSignal(monitor, &info, pid);
break;
@@ -1342,7 +1342,7 @@ ProcessMonitor::GetCrashReasonForSIGSEGV(const siginfo_t *info)
reason = ProcessMessage::eInvalidCrashReason;
switch (info->si_code)
switch (info->si_code)
{
default:
assert(false && "unexpected si_code for SIGSEGV");
@@ -1354,7 +1354,7 @@ ProcessMonitor::GetCrashReasonForSIGSEGV(const siginfo_t *info)
reason = ProcessMessage::ePrivilegedAddress;
break;
}
return reason;
}
@@ -1675,7 +1675,7 @@ ProcessMonitor::Detach()
DoOperation(&op);
StopMonitor();
return result;
}
}
bool
ProcessMonitor::DupDescriptor(const char *path, int fd, int flags)