llvm-project/lldb/source/Symbol/UnwindPlan.cpp

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The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
//===-- UnwindPlan.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/Symbol/UnwindPlan.h"
#include "lldb/Target/Process.h"
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/Log.h"
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
using namespace lldb;
using namespace lldb_private;
bool UnwindPlan::Row::RegisterLocation::
operator==(const UnwindPlan::Row::RegisterLocation &rhs) const {
if (m_type == rhs.m_type) {
switch (m_type) {
case unspecified:
case undefined:
case same:
return true;
case atCFAPlusOffset:
case isCFAPlusOffset:
return m_location.offset == rhs.m_location.offset;
case inOtherRegister:
return m_location.reg_num == rhs.m_location.reg_num;
case atDWARFExpression:
case isDWARFExpression:
if (m_location.expr.length == rhs.m_location.expr.length)
return !memcmp(m_location.expr.opcodes, rhs.m_location.expr.opcodes,
m_location.expr.length);
break;
}
}
return false;
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
}
// This function doesn't copy the dwarf expression bytes; they must remain in
// allocated memory for the lifespan of this UnwindPlan object.
void UnwindPlan::Row::RegisterLocation::SetAtDWARFExpression(
const uint8_t *opcodes, uint32_t len) {
m_type = atDWARFExpression;
m_location.expr.opcodes = opcodes;
m_location.expr.length = len;
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
}
// This function doesn't copy the dwarf expression bytes; they must remain in
// allocated memory for the lifespan of this UnwindPlan object.
void UnwindPlan::Row::RegisterLocation::SetIsDWARFExpression(
const uint8_t *opcodes, uint32_t len) {
m_type = isDWARFExpression;
m_location.expr.opcodes = opcodes;
m_location.expr.length = len;
}
void UnwindPlan::Row::RegisterLocation::Dump(Stream &s,
const UnwindPlan *unwind_plan,
const UnwindPlan::Row *row,
Thread *thread,
bool verbose) const {
switch (m_type) {
case unspecified:
if (verbose)
s.PutCString("=<unspec>");
else
s.PutCString("=!");
break;
case undefined:
if (verbose)
s.PutCString("=<undef>");
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
else
s.PutCString("=?");
break;
case same:
s.PutCString("= <same>");
break;
case atCFAPlusOffset:
case isCFAPlusOffset: {
s.PutChar('=');
if (m_type == atCFAPlusOffset)
s.PutChar('[');
s.Printf("CFA%+d", m_location.offset);
if (m_type == atCFAPlusOffset)
s.PutChar(']');
} break;
case inOtherRegister: {
const RegisterInfo *other_reg_info = nullptr;
if (unwind_plan)
other_reg_info = unwind_plan->GetRegisterInfo(thread, m_location.reg_num);
if (other_reg_info)
s.Printf("=%s", other_reg_info->name);
else
s.Printf("=reg(%u)", m_location.reg_num);
} break;
case atDWARFExpression:
case isDWARFExpression: {
s.PutChar('=');
if (m_type == atDWARFExpression)
s.PutCString("[dwarf-expr]");
else
s.PutCString("dwarf-expr");
} break;
}
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
}
static void DumpRegisterName(Stream &s, const UnwindPlan *unwind_plan,
Thread *thread, uint32_t reg_num) {
const RegisterInfo *reg_info = unwind_plan->GetRegisterInfo(thread, reg_num);
if (reg_info)
s.PutCString(reg_info->name);
else
s.Printf("reg(%u)", reg_num);
}
bool UnwindPlan::Row::CFAValue::
operator==(const UnwindPlan::Row::CFAValue &rhs) const {
if (m_type == rhs.m_type) {
switch (m_type) {
case unspecified:
return true;
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
case isRegisterPlusOffset:
return m_value.reg.offset == rhs.m_value.reg.offset;
case isRegisterDereferenced:
return m_value.reg.reg_num == rhs.m_value.reg.reg_num;
case isDWARFExpression:
if (m_value.expr.length == rhs.m_value.expr.length)
return !memcmp(m_value.expr.opcodes, rhs.m_value.expr.opcodes,
m_value.expr.length);
break;
}
}
return false;
}
void UnwindPlan::Row::CFAValue::Dump(Stream &s, const UnwindPlan *unwind_plan,
Thread *thread) const {
switch (m_type) {
case isRegisterPlusOffset:
DumpRegisterName(s, unwind_plan, thread, m_value.reg.reg_num);
s.Printf("%+3d", m_value.reg.offset);
break;
case isRegisterDereferenced:
s.PutChar('[');
DumpRegisterName(s, unwind_plan, thread, m_value.reg.reg_num);
s.PutChar(']');
break;
case isDWARFExpression:
s.PutCString("dwarf-expr");
break;
default:
s.PutCString("unspecified");
break;
}
}
void UnwindPlan::Row::Clear() {
m_cfa_value.SetUnspecified();
m_offset = 0;
m_register_locations.clear();
}
void UnwindPlan::Row::Dump(Stream &s, const UnwindPlan *unwind_plan,
Thread *thread, addr_t base_addr) const {
if (base_addr != LLDB_INVALID_ADDRESS)
s.Printf("0x%16.16" PRIx64 ": CFA=", base_addr + GetOffset());
else
s.Printf("%4" PRId64 ": CFA=", GetOffset());
m_cfa_value.Dump(s, unwind_plan, thread);
s.Printf(" => ");
for (collection::const_iterator idx = m_register_locations.begin();
idx != m_register_locations.end(); ++idx) {
DumpRegisterName(s, unwind_plan, thread, idx->first);
const bool verbose = false;
idx->second.Dump(s, unwind_plan, this, thread, verbose);
s.PutChar(' ');
}
s.EOL();
}
UnwindPlan::Row::Row() : m_offset(0), m_cfa_value(), m_register_locations() {}
bool UnwindPlan::Row::GetRegisterInfo(
uint32_t reg_num,
UnwindPlan::Row::RegisterLocation &register_location) const {
collection::const_iterator pos = m_register_locations.find(reg_num);
if (pos != m_register_locations.end()) {
register_location = pos->second;
return true;
}
return false;
}
void UnwindPlan::Row::RemoveRegisterInfo(uint32_t reg_num) {
collection::const_iterator pos = m_register_locations.find(reg_num);
if (pos != m_register_locations.end()) {
m_register_locations.erase(pos);
}
}
void UnwindPlan::Row::SetRegisterInfo(
uint32_t reg_num,
const UnwindPlan::Row::RegisterLocation register_location) {
m_register_locations[reg_num] = register_location;
}
bool UnwindPlan::Row::SetRegisterLocationToAtCFAPlusOffset(uint32_t reg_num,
int32_t offset,
bool can_replace) {
if (!can_replace &&
m_register_locations.find(reg_num) != m_register_locations.end())
return false;
RegisterLocation reg_loc;
reg_loc.SetAtCFAPlusOffset(offset);
m_register_locations[reg_num] = reg_loc;
return true;
}
bool UnwindPlan::Row::SetRegisterLocationToIsCFAPlusOffset(uint32_t reg_num,
int32_t offset,
bool can_replace) {
if (!can_replace &&
m_register_locations.find(reg_num) != m_register_locations.end())
return false;
RegisterLocation reg_loc;
reg_loc.SetIsCFAPlusOffset(offset);
m_register_locations[reg_num] = reg_loc;
return true;
}
bool UnwindPlan::Row::SetRegisterLocationToUndefined(
uint32_t reg_num, bool can_replace, bool can_replace_only_if_unspecified) {
collection::iterator pos = m_register_locations.find(reg_num);
collection::iterator end = m_register_locations.end();
if (pos != end) {
if (!can_replace)
return false;
if (can_replace_only_if_unspecified && !pos->second.IsUnspecified())
return false;
}
RegisterLocation reg_loc;
reg_loc.SetUndefined();
m_register_locations[reg_num] = reg_loc;
return true;
}
bool UnwindPlan::Row::SetRegisterLocationToUnspecified(uint32_t reg_num,
bool can_replace) {
if (!can_replace &&
m_register_locations.find(reg_num) != m_register_locations.end())
return false;
RegisterLocation reg_loc;
reg_loc.SetUnspecified();
m_register_locations[reg_num] = reg_loc;
return true;
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
}
bool UnwindPlan::Row::SetRegisterLocationToRegister(uint32_t reg_num,
uint32_t other_reg_num,
bool can_replace) {
if (!can_replace &&
m_register_locations.find(reg_num) != m_register_locations.end())
return false;
RegisterLocation reg_loc;
reg_loc.SetInRegister(other_reg_num);
m_register_locations[reg_num] = reg_loc;
return true;
}
bool UnwindPlan::Row::SetRegisterLocationToSame(uint32_t reg_num,
bool must_replace) {
if (must_replace &&
m_register_locations.find(reg_num) == m_register_locations.end())
return false;
RegisterLocation reg_loc;
reg_loc.SetSame();
m_register_locations[reg_num] = reg_loc;
return true;
}
bool UnwindPlan::Row::operator==(const UnwindPlan::Row &rhs) const {
return m_offset == rhs.m_offset && m_cfa_value == rhs.m_cfa_value &&
m_register_locations == rhs.m_register_locations;
}
void UnwindPlan::AppendRow(const UnwindPlan::RowSP &row_sp) {
if (m_row_list.empty() ||
m_row_list.back()->GetOffset() != row_sp->GetOffset())
m_row_list.push_back(row_sp);
else
m_row_list.back() = row_sp;
}
void UnwindPlan::InsertRow(const UnwindPlan::RowSP &row_sp,
bool replace_existing) {
collection::iterator it = m_row_list.begin();
while (it != m_row_list.end()) {
RowSP row = *it;
if (row->GetOffset() >= row_sp->GetOffset())
break;
it++;
}
if (it == m_row_list.end() || (*it)->GetOffset() != row_sp->GetOffset())
m_row_list.insert(it, row_sp);
else if (replace_existing)
*it = row_sp;
}
UnwindPlan::RowSP UnwindPlan::GetRowForFunctionOffset(int offset) const {
RowSP row;
if (!m_row_list.empty()) {
if (offset == -1)
row = m_row_list.back();
else {
collection::const_iterator pos, end = m_row_list.end();
for (pos = m_row_list.begin(); pos != end; ++pos) {
if ((*pos)->GetOffset() <= static_cast<lldb::offset_t>(offset))
row = *pos;
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
else
break;
}
}
}
return row;
}
bool UnwindPlan::IsValidRowIndex(uint32_t idx) const {
return idx < m_row_list.size();
}
const UnwindPlan::RowSP UnwindPlan::GetRowAtIndex(uint32_t idx) const {
if (idx < m_row_list.size())
return m_row_list[idx];
else {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
if (log)
log->Printf("error: UnwindPlan::GetRowAtIndex(idx = %u) invalid index "
"(number rows is %u)",
idx, (uint32_t)m_row_list.size());
return UnwindPlan::RowSP();
}
}
const UnwindPlan::RowSP UnwindPlan::GetLastRow() const {
if (m_row_list.empty()) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
if (log)
log->Printf("UnwindPlan::GetLastRow() when rows are empty");
return UnwindPlan::RowSP();
}
return m_row_list.back();
}
int UnwindPlan::GetRowCount() const { return m_row_list.size(); }
void UnwindPlan::SetPlanValidAddressRange(const AddressRange &range) {
if (range.GetBaseAddress().IsValid() && range.GetByteSize() != 0)
m_plan_valid_address_range = range;
}
bool UnwindPlan::PlanValidAtAddress(Address addr) {
// If this UnwindPlan has no rows, it is an invalid UnwindPlan.
if (GetRowCount() == 0) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
if (log) {
StreamString s;
if (addr.Dump(&s, nullptr, Address::DumpStyleSectionNameOffset)) {
log->Printf("UnwindPlan is invalid -- no unwind rows for UnwindPlan "
"'%s' at address %s",
m_source_name.GetCString(), s.GetData());
} else {
log->Printf(
"UnwindPlan is invalid -- no unwind rows for UnwindPlan '%s'",
m_source_name.GetCString());
}
}
return false;
}
// If the 0th Row of unwind instructions is missing, or if it doesn't provide
// a register to use to find the Canonical Frame Address, this is not a valid
// UnwindPlan.
if (GetRowAtIndex(0).get() == nullptr ||
GetRowAtIndex(0)->GetCFAValue().GetValueType() ==
Row::CFAValue::unspecified) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND));
if (log) {
StreamString s;
if (addr.Dump(&s, nullptr, Address::DumpStyleSectionNameOffset)) {
log->Printf("UnwindPlan is invalid -- no CFA register defined in row 0 "
"for UnwindPlan '%s' at address %s",
m_source_name.GetCString(), s.GetData());
} else {
log->Printf("UnwindPlan is invalid -- no CFA register defined in row 0 "
"for UnwindPlan '%s'",
m_source_name.GetCString());
}
}
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
return false;
}
The first part of an lldb native stack unwinder. The Unwind and RegisterContext subclasses still need to be finished; none of this code is used by lldb at this point (unless you call into it by hand). The ObjectFile class now has an UnwindTable object. The UnwindTable object has a series of FuncUnwinders objects (Function Unwinders) -- one for each function in that ObjectFile we've backtraced through during this debug session. The FuncUnwinders object has a few different UnwindPlans. UnwindPlans are a generic way of describing how to find the canonical address of a given function's stack frame (the CFA idea from DWARF/eh_frame) and how to restore the caller frame's register values, if they have been saved by this function. UnwindPlans are created from different sources. One source is the eh_frame exception handling information generated by the compiler for unwinding an exception throw. Another source is an assembly language inspection class (UnwindAssemblyProfiler, uses the Plugin architecture) which looks at the instructions in the funciton prologue and describes the stack movements/register saves that are done. Two additional types of UnwindPlans that are worth noting are the "fast" stack UnwindPlan which is useful for making a first pass over a thread's stack, determining how many stack frames there are and retrieving the pc and CFA values for each frame (enough to create StackFrameIDs). Only a minimal set of registers is recovered during a fast stack walk. The final UnwindPlan is an architectural default unwind plan. These are provided by the ArchDefaultUnwindPlan class (which uses the plugin architecture). When no symbol/function address range can be found for a given pc value -- when we have no eh_frame information and when we don't have a start address so we can't examine the assembly language instrucitons -- we have to make a best guess about how to unwind. That's when we use the architectural default UnwindPlan. On x86_64, this would be to assume that rbp is used as a stack pointer and we can use that to find the caller's frame pointer and pc value. It's a last-ditch best guess about how to unwind out of a frame. There are heuristics about when to use one UnwindPlan versues the other -- this will all happen in the still-begin-written UnwindLLDB subclass of Unwind which runs the UnwindPlans. llvm-svn: 113581
2010-09-10 15:49:16 +08:00
if (!m_plan_valid_address_range.GetBaseAddress().IsValid() ||
m_plan_valid_address_range.GetByteSize() == 0)
return true;
if (!addr.IsValid())
return true;
if (m_plan_valid_address_range.ContainsFileAddress(addr))
return true;
return false;
}
void UnwindPlan::Dump(Stream &s, Thread *thread, lldb::addr_t base_addr) const {
if (!m_source_name.IsEmpty()) {
s.Printf("This UnwindPlan originally sourced from %s\n",
m_source_name.GetCString());
}
if (m_lsda_address.IsValid() && m_personality_func_addr.IsValid()) {
TargetSP target_sp(thread->CalculateTarget());
addr_t lsda_load_addr = m_lsda_address.GetLoadAddress(target_sp.get());
addr_t personality_func_load_addr =
m_personality_func_addr.GetLoadAddress(target_sp.get());
if (lsda_load_addr != LLDB_INVALID_ADDRESS &&
personality_func_load_addr != LLDB_INVALID_ADDRESS) {
s.Printf("LSDA address 0x%" PRIx64
", personality routine is at address 0x%" PRIx64 "\n",
lsda_load_addr, personality_func_load_addr);
}
}
s.Printf("This UnwindPlan is sourced from the compiler: ");
switch (m_plan_is_sourced_from_compiler) {
case eLazyBoolYes:
s.Printf("yes.\n");
break;
case eLazyBoolNo:
s.Printf("no.\n");
break;
case eLazyBoolCalculate:
s.Printf("not specified.\n");
break;
}
s.Printf("This UnwindPlan is valid at all instruction locations: ");
switch (m_plan_is_valid_at_all_instruction_locations) {
case eLazyBoolYes:
s.Printf("yes.\n");
break;
case eLazyBoolNo:
s.Printf("no.\n");
break;
case eLazyBoolCalculate:
s.Printf("not specified.\n");
break;
}
if (m_plan_valid_address_range.GetBaseAddress().IsValid() &&
m_plan_valid_address_range.GetByteSize() > 0) {
s.PutCString("Address range of this UnwindPlan: ");
TargetSP target_sp(thread->CalculateTarget());
m_plan_valid_address_range.Dump(&s, target_sp.get(),
Address::DumpStyleSectionNameOffset);
s.EOL();
}
collection::const_iterator pos, begin = m_row_list.begin(),
end = m_row_list.end();
for (pos = begin; pos != end; ++pos) {
s.Printf("row[%u]: ", (uint32_t)std::distance(begin, pos));
(*pos)->Dump(s, this, thread, base_addr);
}
}
void UnwindPlan::SetSourceName(const char *source) {
m_source_name = ConstString(source);
}
ConstString UnwindPlan::GetSourceName() const { return m_source_name; }
const RegisterInfo *UnwindPlan::GetRegisterInfo(Thread *thread,
uint32_t unwind_reg) const {
if (thread) {
RegisterContext *reg_ctx = thread->GetRegisterContext().get();
if (reg_ctx) {
uint32_t reg;
if (m_register_kind == eRegisterKindLLDB)
reg = unwind_reg;
else
reg = reg_ctx->ConvertRegisterKindToRegisterNumber(m_register_kind,
unwind_reg);
if (reg != LLDB_INVALID_REGNUM)
return reg_ctx->GetRegisterInfoAtIndex(reg);
}
}
return nullptr;
}