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llvm-capstone/lldb/source/Expression/IRMemoryMap.cpp
Zachary Turner 3ddcd314f2 Dont' use a random probe & alloc strategy for the IRMemoryMap. 
The current strategy for host allocation is to choose a random
address and attempt to allocate there, eventually failing if the
allocation cannot be satisfied.

The C standard only guarantees that RAND_MAX >= 32767, so for
platforms that use a very small RAND_MAX allocations will fail
with very high probability.  On such platforms (Windows is one),
you can reproduce this trivially by running lldb, typing "expr (3)"
and then hitting enter you see a failure.  Failures generally
happen with a frequency of about 1 failure every 5 evaluations.

There is no good reason that allocations need to look like "real"
pointers, so this patch changes the allocation scheme to simply
jump straight to the end and grab a free chunk of memory.

Reviewed By: Sean Callanan

Differential Revision: http://reviews.llvm.org/D4300

llvm-svn: 212630
2014-07-09 16:42:27 +00:00

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//===-- IRMemoryMap.cpp -----------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Expression/IRMemoryMap.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
using namespace lldb_private;
IRMemoryMap::IRMemoryMap (lldb::TargetSP target_sp) :
m_target_wp(target_sp)
{
if (target_sp)
m_process_wp = target_sp->GetProcessSP();
}
IRMemoryMap::~IRMemoryMap ()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
AllocationMap::iterator iter;
Error err;
while ((iter = m_allocations.begin()) != m_allocations.end())
{
err.Clear();
if (iter->second.m_leak)
m_allocations.erase(iter);
else
Free(iter->first, err);
}
}
}
lldb::addr_t
IRMemoryMap::FindSpace (size_t size)
{
lldb::TargetSP target_sp = m_target_wp.lock();
lldb::ProcessSP process_sp = m_process_wp.lock();
lldb::addr_t ret = LLDB_INVALID_ADDRESS;
if (size == 0)
return ret;
if (process_sp && process_sp->CanJIT() && process_sp->IsAlive())
{
Error alloc_error;
ret = process_sp->AllocateMemory(size, lldb::ePermissionsReadable | lldb::ePermissionsWritable, alloc_error);
if (!alloc_error.Success())
return LLDB_INVALID_ADDRESS;
else
return ret;
}
ret = 0;
if (!m_allocations.empty())
{
auto back = m_allocations.rbegin();
lldb::addr_t addr = back->first;
size_t alloc_size = back->second.m_size;
ret = llvm::RoundUpToAlignment(addr+alloc_size, 4096);
}
return ret;
}
IRMemoryMap::AllocationMap::iterator
IRMemoryMap::FindAllocation (lldb::addr_t addr, size_t size)
{
if (addr == LLDB_INVALID_ADDRESS)
return m_allocations.end();
AllocationMap::iterator iter = m_allocations.lower_bound (addr);
if (iter == m_allocations.end() ||
iter->first > addr)
{
if (iter == m_allocations.begin())
return m_allocations.end();
iter--;
}
if (iter->first <= addr && iter->first + iter->second.m_size >= addr + size)
return iter;
return m_allocations.end();
}
bool
IRMemoryMap::IntersectsAllocation (lldb::addr_t addr, size_t size) const
{
if (addr == LLDB_INVALID_ADDRESS)
return false;
AllocationMap::const_iterator iter = m_allocations.lower_bound (addr);
// Since we only know that the returned interval begins at a location greater than or
// equal to where the given interval begins, it's possible that the given interval
// intersects either the returned interval or the previous interval. Thus, we need to
// check both. Note that we only need to check these two intervals. Since all intervals
// are disjoint it is not possible that an adjacent interval does not intersect, but a
// non-adjacent interval does intersect.
if (iter != m_allocations.end()) {
if (AllocationsIntersect(addr, size, iter->second.m_process_start, iter->second.m_size))
return true;
}
if (iter != m_allocations.begin()) {
--iter;
if (AllocationsIntersect(addr, size, iter->second.m_process_start, iter->second.m_size))
return true;
}
return false;
}
bool
IRMemoryMap::AllocationsIntersect(lldb::addr_t addr1, size_t size1, lldb::addr_t addr2, size_t size2) {
// Given two half open intervals [A, B) and [X, Y), the only 6 permutations that satisfy
// A<B and X<Y are the following:
// A B X Y
// A X B Y (intersects)
// A X Y B (intersects)
// X A B Y (intersects)
// X A Y B (intersects)
// X Y A B
// The first is B <= X, and the last is Y <= A.
// So the condition is !(B <= X || Y <= A)), or (X < B && A < Y)
return (addr2 < (addr1 + size1)) && (addr1 < (addr2 + size2));
}
lldb::ByteOrder
IRMemoryMap::GetByteOrder()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp->GetByteOrder();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp->GetArchitecture().GetByteOrder();
return lldb::eByteOrderInvalid;
}
uint32_t
IRMemoryMap::GetAddressByteSize()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp->GetAddressByteSize();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp->GetArchitecture().GetAddressByteSize();
return UINT32_MAX;
}
ExecutionContextScope *
IRMemoryMap::GetBestExecutionContextScope() const
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp.get();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp.get();
return NULL;
}
IRMemoryMap::Allocation::Allocation (lldb::addr_t process_alloc,
lldb::addr_t process_start,
size_t size,
uint32_t permissions,
uint8_t alignment,
AllocationPolicy policy) :
m_process_alloc (process_alloc),
m_process_start (process_start),
m_size (size),
m_permissions (permissions),
m_alignment (alignment),
m_policy (policy),
m_leak (false)
{
switch (policy)
{
default:
assert (0 && "We cannot reach this!");
case eAllocationPolicyHostOnly:
m_data.SetByteSize(size);
memset(m_data.GetBytes(), 0, size);
break;
case eAllocationPolicyProcessOnly:
break;
case eAllocationPolicyMirror:
m_data.SetByteSize(size);
memset(m_data.GetBytes(), 0, size);
break;
}
}
lldb::addr_t
IRMemoryMap::Malloc (size_t size, uint8_t alignment, uint32_t permissions, AllocationPolicy policy, Error &error)
{
lldb_private::Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
error.Clear();
lldb::ProcessSP process_sp;
lldb::addr_t allocation_address = LLDB_INVALID_ADDRESS;
lldb::addr_t aligned_address = LLDB_INVALID_ADDRESS;
size_t alignment_mask = alignment - 1;
size_t allocation_size;
if (size == 0)
allocation_size = alignment;
else
allocation_size = (size & alignment_mask) ? ((size + alignment) & (~alignment_mask)) : size;
switch (policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: invalid allocation policy");
return LLDB_INVALID_ADDRESS;
case eAllocationPolicyHostOnly:
allocation_address = FindSpace(allocation_size);
if (allocation_address == LLDB_INVALID_ADDRESS)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: address space is full");
return LLDB_INVALID_ADDRESS;
}
break;
case eAllocationPolicyMirror:
process_sp = m_process_wp.lock();
if (log)
log->Printf ("IRMemoryMap::%s process_sp=0x%" PRIx64 ", process_sp->CanJIT()=%s, process_sp->IsAlive()=%s", __FUNCTION__, (lldb::addr_t) process_sp.get (), process_sp && process_sp->CanJIT () ? "true" : "false", process_sp && process_sp->IsAlive () ? "true" : "false");
if (process_sp && process_sp->CanJIT() && process_sp->IsAlive())
{
allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
if (!error.Success())
return LLDB_INVALID_ADDRESS;
}
else
{
if (log)
log->Printf ("IRMemoryMap::%s switching to eAllocationPolicyHostOnly due to failed condition (see previous expr log message)", __FUNCTION__);
policy = eAllocationPolicyHostOnly;
allocation_address = FindSpace(allocation_size);
if (allocation_address == LLDB_INVALID_ADDRESS)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: address space is full");
return LLDB_INVALID_ADDRESS;
}
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
if (process_sp->CanJIT() && process_sp->IsAlive())
{
allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
if (!error.Success())
return LLDB_INVALID_ADDRESS;
}
else
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: process doesn't support allocating memory");
return LLDB_INVALID_ADDRESS;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: process doesn't exist, and this memory must be in the process");
return LLDB_INVALID_ADDRESS;
}
break;
}
lldb::addr_t mask = alignment - 1;
aligned_address = (allocation_address + mask) & (~mask);
m_allocations[aligned_address] = Allocation(allocation_address,
aligned_address,
allocation_size,
permissions,
alignment,
policy);
if (log)
{
const char * policy_string;
switch (policy)
{
default:
policy_string = "<invalid policy>";
break;
case eAllocationPolicyHostOnly:
policy_string = "eAllocationPolicyHostOnly";
break;
case eAllocationPolicyProcessOnly:
policy_string = "eAllocationPolicyProcessOnly";
break;
case eAllocationPolicyMirror:
policy_string = "eAllocationPolicyMirror";
break;
}
log->Printf("IRMemoryMap::Malloc (%" PRIu64 ", 0x%" PRIx64 ", 0x%" PRIx64 ", %s) -> 0x%" PRIx64,
(uint64_t)allocation_size,
(uint64_t)alignment,
(uint64_t)permissions,
policy_string,
aligned_address);
}
return aligned_address;
}
void
IRMemoryMap::Leak (lldb::addr_t process_address, Error &error)
{
error.Clear();
AllocationMap::iterator iter = m_allocations.find(process_address);
if (iter == m_allocations.end())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't leak: allocation doesn't exist");
return;
}
Allocation &allocation = iter->second;
allocation.m_leak = true;
}
void
IRMemoryMap::Free (lldb::addr_t process_address, Error &error)
{
error.Clear();
AllocationMap::iterator iter = m_allocations.find(process_address);
if (iter == m_allocations.end())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't free: allocation doesn't exist");
return;
}
Allocation &allocation = iter->second;
switch (allocation.m_policy)
{
default:
case eAllocationPolicyHostOnly:
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
if (process_sp->CanJIT() && process_sp->IsAlive())
process_sp->DeallocateMemory(allocation.m_process_alloc); // FindSpace allocated this for real
}
break;
}
case eAllocationPolicyMirror:
case eAllocationPolicyProcessOnly:
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
process_sp->DeallocateMemory(allocation.m_process_alloc);
}
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::Free (0x%" PRIx64 ") freed [0x%" PRIx64 "..0x%" PRIx64 ")",
(uint64_t)process_address,
iter->second.m_process_start,
iter->second.m_process_start + iter->second.m_size);
}
m_allocations.erase(iter);
}
void
IRMemoryMap::WriteMemory (lldb::addr_t process_address, const uint8_t *bytes, size_t size, Error &error)
{
error.Clear();
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
return;
}
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: no allocation contains the target range and the process doesn't exist");
return;
}
Allocation &allocation = iter->second;
uint64_t offset = process_address - allocation.m_process_start;
lldb::ProcessSP process_sp;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: invalid allocation policy");
return;
case eAllocationPolicyHostOnly:
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: data buffer is empty");
return;
}
::memcpy (allocation.m_data.GetBytes() + offset, bytes, size);
break;
case eAllocationPolicyMirror:
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: data buffer is empty");
return;
}
::memcpy (allocation.m_data.GetBytes() + offset, bytes, size);
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::WriteMemory (0x%" PRIx64 ", 0x%" PRIx64 ", 0x%" PRId64 ") went to [0x%" PRIx64 "..0x%" PRIx64 ")",
(uint64_t)process_address,
(uint64_t)bytes,
(uint64_t)size,
(uint64_t)allocation.m_process_start,
(uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
}
}
void
IRMemoryMap::WriteScalarToMemory (lldb::addr_t process_address, Scalar &scalar, size_t size, Error &error)
{
error.Clear();
if (size == UINT32_MAX)
size = scalar.GetByteSize();
if (size > 0)
{
uint8_t buf[32];
const size_t mem_size = scalar.GetAsMemoryData (buf, size, GetByteOrder(), error);
if (mem_size > 0)
{
return WriteMemory(process_address, buf, mem_size, error);
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't write scalar: failed to get scalar as memory data");
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't write scalar: its size was zero");
}
return;
}
void
IRMemoryMap::WritePointerToMemory (lldb::addr_t process_address, lldb::addr_t address, Error &error)
{
error.Clear();
Scalar scalar(address);
WriteScalarToMemory(process_address, scalar, GetAddressByteSize(), error);
}
void
IRMemoryMap::ReadMemory (uint8_t *bytes, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
return;
}
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
{
Address absolute_address(process_address);
target_sp->ReadMemory(absolute_address, false, bytes, size, error);
return;
}
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: no allocation contains the target range, and neither the process nor the target exist");
return;
}
Allocation &allocation = iter->second;
uint64_t offset = process_address - allocation.m_process_start;
if (offset > allocation.m_size)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: data is not in the allocation");
return;
}
lldb::ProcessSP process_sp;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: invalid allocation policy");
return;
case eAllocationPolicyHostOnly:
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: data buffer is empty");
return;
}
if (allocation.m_data.GetByteSize() < offset + size)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: not enough underlying data");
return;
}
::memcpy (bytes, allocation.m_data.GetBytes() + offset, size);
break;
case eAllocationPolicyMirror:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
else
{
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: data buffer is empty");
return;
}
::memcpy (bytes, allocation.m_data.GetBytes() + offset, size);
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::ReadMemory (0x%" PRIx64 ", 0x%" PRIx64 ", 0x%" PRId64 ") came from [0x%" PRIx64 "..0x%" PRIx64 ")",
(uint64_t)process_address,
(uint64_t)bytes,
(uint64_t)size,
(uint64_t)allocation.m_process_start,
(uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
}
}
void
IRMemoryMap::ReadScalarFromMemory (Scalar &scalar, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
if (size > 0)
{
DataBufferHeap buf(size, 0);
ReadMemory(buf.GetBytes(), process_address, size, error);
if (!error.Success())
return;
DataExtractor extractor(buf.GetBytes(), buf.GetByteSize(), GetByteOrder(), GetAddressByteSize());
lldb::offset_t offset = 0;
switch (size)
{
default:
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Couldn't read scalar: unsupported size %" PRIu64, (uint64_t)size);
return;
case 1: scalar = extractor.GetU8(&offset); break;
case 2: scalar = extractor.GetU16(&offset); break;
case 4: scalar = extractor.GetU32(&offset); break;
case 8: scalar = extractor.GetU64(&offset); break;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't read scalar: its size was zero");
}
return;
}
void
IRMemoryMap::ReadPointerFromMemory (lldb::addr_t *address, lldb::addr_t process_address, Error &error)
{
error.Clear();
Scalar pointer_scalar;
ReadScalarFromMemory(pointer_scalar, process_address, GetAddressByteSize(), error);
if (!error.Success())
return;
*address = pointer_scalar.ULongLong();
return;
}
void
IRMemoryMap::GetMemoryData (DataExtractor &extractor, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
if (size > 0)
{
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Couldn't find an allocation containing [0x%" PRIx64 "..0x%" PRIx64 ")", process_address, process_address + size);
return;
}
Allocation &allocation = iter->second;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: invalid allocation policy");
return;
case eAllocationPolicyProcessOnly:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: memory is only in the target");
return;
case eAllocationPolicyMirror:
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: data buffer is empty");
return;
}
if (process_sp)
{
process_sp->ReadMemory(allocation.m_process_start, allocation.m_data.GetBytes(), allocation.m_data.GetByteSize(), error);
if (!error.Success())
return;
uint64_t offset = process_address - allocation.m_process_start;
extractor = DataExtractor(allocation.m_data.GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
return;
}
}
case eAllocationPolicyHostOnly:
if (!allocation.m_data.GetByteSize())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: data buffer is empty");
return;
}
uint64_t offset = process_address - allocation.m_process_start;
extractor = DataExtractor(allocation.m_data.GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
return;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't get memory data: its size was zero");
return;
}
}
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