mirror of
https://github.com/encounter/objdiff.git
synced 2025-12-18 09:25:22 +00:00
849 lines
35 KiB
Rust
849 lines
35 KiB
Rust
use alloc::{
|
|
collections::{BTreeMap, BTreeSet},
|
|
string::{String, ToString},
|
|
vec,
|
|
vec::Vec,
|
|
};
|
|
|
|
use anyhow::{Result, bail, ensure};
|
|
use cwextab::{ExceptionTableData, decode_extab};
|
|
use flagset::Flags;
|
|
use object::{Object as _, ObjectSection as _, ObjectSymbol as _, elf};
|
|
|
|
use crate::{
|
|
arch::{Arch, DataType},
|
|
diff::{
|
|
DiffObjConfig,
|
|
data::resolve_relocation,
|
|
display::{ContextItem, HoverItem, HoverItemColor, InstructionPart, SymbolNavigationKind},
|
|
},
|
|
obj::{
|
|
InstructionRef, Object, Relocation, RelocationFlags, ResolvedInstructionRef,
|
|
ResolvedRelocation, ScannedInstruction, Symbol, SymbolFlag, SymbolFlagSet,
|
|
},
|
|
};
|
|
|
|
// Relative relocation, can be Simm, Offset or BranchDest
|
|
fn is_relative_arg(arg: &ppc750cl::Argument) -> bool {
|
|
matches!(
|
|
arg,
|
|
ppc750cl::Argument::Simm(_)
|
|
| ppc750cl::Argument::Offset(_)
|
|
| ppc750cl::Argument::BranchDest(_)
|
|
)
|
|
}
|
|
|
|
// Relative or absolute relocation, can be Uimm, Simm or Offset
|
|
fn is_rel_abs_arg(arg: &ppc750cl::Argument) -> bool {
|
|
matches!(
|
|
arg,
|
|
ppc750cl::Argument::Uimm(_) | ppc750cl::Argument::Simm(_) | ppc750cl::Argument::Offset(_)
|
|
)
|
|
}
|
|
|
|
fn is_offset_arg(arg: &ppc750cl::Argument) -> bool { matches!(arg, ppc750cl::Argument::Offset(_)) }
|
|
|
|
#[derive(Debug)]
|
|
pub struct ArchPpc {
|
|
/// Exception info
|
|
pub extab: Option<BTreeMap<usize, ExceptionInfo>>,
|
|
}
|
|
|
|
impl ArchPpc {
|
|
pub fn new(file: &object::File) -> Result<Self> {
|
|
Ok(Self { extab: decode_exception_info(file)? })
|
|
}
|
|
|
|
fn parse_ins_ref(&self, resolved: ResolvedInstructionRef) -> Result<ppc750cl::Ins> {
|
|
let mut code = u32::from_be_bytes(resolved.code.try_into()?);
|
|
if let Some(reloc) = resolved.relocation {
|
|
code = zero_reloc(code, reloc.relocation);
|
|
}
|
|
let op = ppc750cl::Opcode::from(resolved.ins_ref.opcode as u8);
|
|
Ok(ppc750cl::Ins { code, op })
|
|
}
|
|
|
|
fn find_reloc_arg(
|
|
&self,
|
|
ins: &ppc750cl::ParsedIns,
|
|
resolved: Option<ResolvedRelocation>,
|
|
) -> Option<usize> {
|
|
match resolved?.relocation.flags {
|
|
RelocationFlags::Elf(elf::R_PPC_EMB_SDA21) => Some(1),
|
|
RelocationFlags::Elf(elf::R_PPC_REL24 | elf::R_PPC_REL14) => {
|
|
ins.args.iter().rposition(is_relative_arg)
|
|
}
|
|
RelocationFlags::Elf(
|
|
elf::R_PPC_ADDR16_HI | elf::R_PPC_ADDR16_HA | elf::R_PPC_ADDR16_LO,
|
|
) => ins.args.iter().rposition(is_rel_abs_arg),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Arch for ArchPpc {
|
|
fn scan_instructions(
|
|
&self,
|
|
address: u64,
|
|
code: &[u8],
|
|
_section_index: usize,
|
|
_relocations: &[Relocation],
|
|
_diff_config: &DiffObjConfig,
|
|
) -> Result<Vec<ScannedInstruction>> {
|
|
ensure!(code.len() & 3 == 0, "Code length must be a multiple of 4");
|
|
let ins_count = code.len() / 4;
|
|
let mut insts = Vec::<ScannedInstruction>::with_capacity(ins_count);
|
|
for (cur_addr, ins) in ppc750cl::InsIter::new(code, address as u32) {
|
|
insts.push(ScannedInstruction {
|
|
ins_ref: InstructionRef {
|
|
address: cur_addr as u64,
|
|
size: 4,
|
|
opcode: u8::from(ins.op) as u16,
|
|
},
|
|
branch_dest: ins.branch_dest(cur_addr).map(u64::from),
|
|
});
|
|
}
|
|
Ok(insts)
|
|
}
|
|
|
|
fn display_instruction(
|
|
&self,
|
|
resolved: ResolvedInstructionRef,
|
|
_diff_config: &DiffObjConfig,
|
|
cb: &mut dyn FnMut(InstructionPart) -> Result<()>,
|
|
) -> Result<()> {
|
|
let ins = self.parse_ins_ref(resolved)?.simplified();
|
|
|
|
cb(InstructionPart::opcode(ins.mnemonic, resolved.ins_ref.opcode))?;
|
|
|
|
let reloc_arg = self.find_reloc_arg(&ins, resolved.relocation);
|
|
|
|
let mut writing_offset = false;
|
|
for (idx, arg) in ins.args_iter().enumerate() {
|
|
if idx > 0 && !writing_offset {
|
|
cb(InstructionPart::separator())?;
|
|
}
|
|
|
|
if reloc_arg == Some(idx) {
|
|
let reloc = resolved.relocation.unwrap();
|
|
display_reloc(reloc, cb)?;
|
|
// For @sda21, we can omit the register argument
|
|
if matches!(reloc.relocation.flags, RelocationFlags::Elf(elf::R_PPC_EMB_SDA21))
|
|
// Sanity check: the next argument should be r0
|
|
&& matches!(ins.args.get(idx + 1), Some(ppc750cl::Argument::GPR(ppc750cl::GPR(0))))
|
|
{
|
|
break;
|
|
}
|
|
} else {
|
|
match arg {
|
|
ppc750cl::Argument::Simm(simm) => cb(InstructionPart::signed(simm.0)),
|
|
ppc750cl::Argument::Uimm(uimm) => cb(InstructionPart::unsigned(uimm.0)),
|
|
ppc750cl::Argument::Offset(offset) => cb(InstructionPart::signed(offset.0)),
|
|
ppc750cl::Argument::BranchDest(dest) => cb(InstructionPart::branch_dest(
|
|
(resolved.ins_ref.address as u32).wrapping_add_signed(dest.0),
|
|
)),
|
|
_ => cb(InstructionPart::opaque(arg.to_string())),
|
|
}?;
|
|
}
|
|
|
|
if writing_offset {
|
|
cb(InstructionPart::basic(")"))?;
|
|
writing_offset = false;
|
|
}
|
|
if is_offset_arg(arg) {
|
|
cb(InstructionPart::basic("("))?;
|
|
writing_offset = true;
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
fn generate_pooled_relocations(
|
|
&self,
|
|
address: u64,
|
|
code: &[u8],
|
|
relocations: &[Relocation],
|
|
symbols: &[Symbol],
|
|
) -> Vec<Relocation> {
|
|
generate_fake_pool_relocations_for_function(address, code, relocations, symbols)
|
|
}
|
|
|
|
fn implcit_addend(
|
|
&self,
|
|
_file: &object::File<'_>,
|
|
_section: &object::Section,
|
|
address: u64,
|
|
_relocation: &object::Relocation,
|
|
flags: RelocationFlags,
|
|
) -> Result<i64> {
|
|
bail!("Unsupported PPC implicit relocation {:#x}:{:?}", address, flags)
|
|
}
|
|
|
|
fn demangle(&self, name: &str) -> Option<String> {
|
|
cwdemangle::demangle(name, &cwdemangle::DemangleOptions::default())
|
|
}
|
|
|
|
fn reloc_name(&self, flags: RelocationFlags) -> Option<&'static str> {
|
|
match flags {
|
|
RelocationFlags::Elf(r_type) => match r_type {
|
|
elf::R_PPC_NONE => Some("R_PPC_NONE"), // We use this for fake pool relocs
|
|
elf::R_PPC_ADDR16_LO => Some("R_PPC_ADDR16_LO"),
|
|
elf::R_PPC_ADDR16_HI => Some("R_PPC_ADDR16_HI"),
|
|
elf::R_PPC_ADDR16_HA => Some("R_PPC_ADDR16_HA"),
|
|
elf::R_PPC_EMB_SDA21 => Some("R_PPC_EMB_SDA21"),
|
|
elf::R_PPC_ADDR32 => Some("R_PPC_ADDR32"),
|
|
elf::R_PPC_UADDR32 => Some("R_PPC_UADDR32"),
|
|
elf::R_PPC_REL24 => Some("R_PPC_REL24"),
|
|
elf::R_PPC_REL14 => Some("R_PPC_REL14"),
|
|
_ => None,
|
|
},
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
fn data_reloc_size(&self, flags: RelocationFlags) -> usize {
|
|
match flags {
|
|
RelocationFlags::Elf(r_type) => match r_type {
|
|
elf::R_PPC_ADDR32 => 4,
|
|
elf::R_PPC_UADDR32 => 4,
|
|
_ => 1,
|
|
},
|
|
_ => 1,
|
|
}
|
|
}
|
|
|
|
fn extra_symbol_flags(&self, symbol: &object::Symbol) -> SymbolFlagSet {
|
|
if self.extab.as_ref().is_some_and(|extab| extab.contains_key(&(symbol.index().0 - 1))) {
|
|
SymbolFlag::HasExtra.into()
|
|
} else {
|
|
SymbolFlag::none()
|
|
}
|
|
}
|
|
|
|
fn guess_data_type(&self, resolved: ResolvedInstructionRef) -> Option<DataType> {
|
|
if resolved.relocation.is_some_and(|r| r.symbol.name.starts_with("@stringBase")) {
|
|
return Some(DataType::String);
|
|
}
|
|
let opcode = ppc750cl::Opcode::from(resolved.ins_ref.opcode as u8);
|
|
guess_data_type_from_load_store_inst_op(opcode)
|
|
}
|
|
|
|
fn symbol_hover(&self, _obj: &Object, symbol_index: usize) -> Vec<HoverItem> {
|
|
let mut out = Vec::new();
|
|
if let Some(extab) = self.extab_for_symbol(symbol_index) {
|
|
out.push(HoverItem::Text {
|
|
label: "extab symbol".into(),
|
|
value: extab.etb_symbol.name.clone(),
|
|
color: HoverItemColor::Special,
|
|
});
|
|
out.push(HoverItem::Text {
|
|
label: "extabindex symbol".into(),
|
|
value: extab.eti_symbol.name.clone(),
|
|
color: HoverItemColor::Special,
|
|
});
|
|
}
|
|
out
|
|
}
|
|
|
|
fn symbol_context(&self, _obj: &Object, symbol_index: usize) -> Vec<ContextItem> {
|
|
let mut out = Vec::new();
|
|
if let Some(_extab) = self.extab_for_symbol(symbol_index) {
|
|
out.push(ContextItem::Navigate {
|
|
label: "Decode exception table".to_string(),
|
|
symbol_index,
|
|
kind: SymbolNavigationKind::Extab,
|
|
});
|
|
}
|
|
out
|
|
}
|
|
|
|
fn instruction_hover(&self, _obj: &Object, resolved: ResolvedInstructionRef) -> Vec<HoverItem> {
|
|
let Ok(ins) = self.parse_ins_ref(resolved) else {
|
|
return Vec::new();
|
|
};
|
|
let orig = ins.basic().to_string();
|
|
let simplified = ins.simplified().to_string();
|
|
let show_orig = orig != simplified;
|
|
let rlwinm_decoded = rlwinmdec::decode(&orig);
|
|
let mut out = Vec::with_capacity(2);
|
|
if show_orig {
|
|
out.push(HoverItem::Text {
|
|
label: "Original".into(),
|
|
value: orig,
|
|
color: HoverItemColor::Normal,
|
|
});
|
|
}
|
|
if let Some(decoded) = rlwinm_decoded {
|
|
for line in decoded.lines() {
|
|
out.push(HoverItem::Text {
|
|
label: Default::default(),
|
|
value: line.to_string(),
|
|
color: HoverItemColor::Special,
|
|
});
|
|
}
|
|
}
|
|
out
|
|
}
|
|
|
|
fn instruction_context(
|
|
&self,
|
|
_obj: &Object,
|
|
resolved: ResolvedInstructionRef,
|
|
) -> Vec<ContextItem> {
|
|
let Ok(ins) = self.parse_ins_ref(resolved) else {
|
|
return Vec::new();
|
|
};
|
|
let orig = ins.basic().to_string();
|
|
let simplified = ins.simplified().to_string();
|
|
let show_orig = orig != simplified;
|
|
let mut out = Vec::with_capacity(2);
|
|
out.push(ContextItem::Copy { value: simplified, label: None });
|
|
if show_orig {
|
|
out.push(ContextItem::Copy { value: orig, label: Some("original".to_string()) });
|
|
}
|
|
out
|
|
}
|
|
}
|
|
|
|
impl ArchPpc {
|
|
pub fn extab_for_symbol(&self, symbol_index: usize) -> Option<&ExceptionInfo> {
|
|
self.extab.as_ref()?.get(&symbol_index)
|
|
}
|
|
}
|
|
|
|
fn zero_reloc(code: u32, reloc: &Relocation) -> u32 {
|
|
match reloc.flags {
|
|
RelocationFlags::Elf(elf::R_PPC_EMB_SDA21) => code & !0x1FFFFF,
|
|
RelocationFlags::Elf(elf::R_PPC_REL24) => code & !0x3FFFFFC,
|
|
RelocationFlags::Elf(elf::R_PPC_REL14) => code & !0xFFFC,
|
|
RelocationFlags::Elf(
|
|
elf::R_PPC_ADDR16_HI | elf::R_PPC_ADDR16_HA | elf::R_PPC_ADDR16_LO,
|
|
) => code & !0xFFFF,
|
|
_ => code,
|
|
}
|
|
}
|
|
|
|
fn display_reloc(
|
|
resolved: ResolvedRelocation,
|
|
cb: &mut dyn FnMut(InstructionPart) -> Result<()>,
|
|
) -> Result<()> {
|
|
match resolved.relocation.flags {
|
|
RelocationFlags::Elf(r_type) => match r_type {
|
|
elf::R_PPC_ADDR16_LO => {
|
|
cb(InstructionPart::reloc())?;
|
|
cb(InstructionPart::basic("@l"))?;
|
|
}
|
|
elf::R_PPC_ADDR16_HI => {
|
|
cb(InstructionPart::reloc())?;
|
|
cb(InstructionPart::basic("@h"))?;
|
|
}
|
|
elf::R_PPC_ADDR16_HA => {
|
|
cb(InstructionPart::reloc())?;
|
|
cb(InstructionPart::basic("@ha"))?;
|
|
}
|
|
elf::R_PPC_EMB_SDA21 => {
|
|
cb(InstructionPart::reloc())?;
|
|
cb(InstructionPart::basic("@sda21"))?;
|
|
}
|
|
elf::R_PPC_ADDR32 | elf::R_PPC_UADDR32 | elf::R_PPC_REL24 | elf::R_PPC_REL14 => {
|
|
cb(InstructionPart::reloc())?;
|
|
}
|
|
elf::R_PPC_NONE => {
|
|
// Fake pool relocation.
|
|
cb(InstructionPart::basic("<"))?;
|
|
cb(InstructionPart::reloc())?;
|
|
cb(InstructionPart::basic(">"))?;
|
|
}
|
|
_ => cb(InstructionPart::reloc())?,
|
|
},
|
|
_ => cb(InstructionPart::reloc())?,
|
|
};
|
|
Ok(())
|
|
}
|
|
|
|
#[derive(Debug, Clone)]
|
|
pub struct ExtabSymbolRef {
|
|
pub original_index: usize,
|
|
pub name: String,
|
|
pub demangled_name: Option<String>,
|
|
}
|
|
|
|
#[derive(Debug, Clone)]
|
|
pub struct ExceptionInfo {
|
|
pub eti_symbol: ExtabSymbolRef,
|
|
pub etb_symbol: ExtabSymbolRef,
|
|
pub data: ExceptionTableData,
|
|
pub dtors: Vec<ExtabSymbolRef>,
|
|
}
|
|
|
|
fn decode_exception_info(
|
|
file: &object::File<'_>,
|
|
) -> Result<Option<BTreeMap<usize, ExceptionInfo>>> {
|
|
let Some(extab_section) = file.section_by_name("extab") else {
|
|
return Ok(None);
|
|
};
|
|
let Some(extabindex_section) = file.section_by_name("extabindex") else {
|
|
return Ok(None);
|
|
};
|
|
|
|
let mut result = BTreeMap::new();
|
|
let extab_relocations =
|
|
extab_section.relocations().collect::<BTreeMap<u64, object::Relocation>>();
|
|
let extabindex_relocations =
|
|
extabindex_section.relocations().collect::<BTreeMap<u64, object::Relocation>>();
|
|
|
|
for extabindex in file.symbols().filter(|symbol| {
|
|
symbol.section_index() == Some(extabindex_section.index())
|
|
&& symbol.kind() == object::SymbolKind::Data
|
|
}) {
|
|
if extabindex.size() != 12 {
|
|
log::warn!("Invalid extabindex entry size {}", extabindex.size());
|
|
continue;
|
|
}
|
|
|
|
// Each extabindex entry has two relocations:
|
|
// - 0x0: The function that the exception table is for
|
|
// - 0x8: The relevant entry in extab section
|
|
let Some(extab_func_reloc) = extabindex_relocations.get(&extabindex.address()) else {
|
|
log::warn!("Failed to find function relocation for extabindex entry");
|
|
continue;
|
|
};
|
|
let Some(extab_reloc) = extabindex_relocations.get(&(extabindex.address() + 8)) else {
|
|
log::warn!("Failed to find extab relocation for extabindex entry");
|
|
continue;
|
|
};
|
|
|
|
// Resolve the function and extab symbols
|
|
let Some(extab_func) = relocation_symbol(file, extab_func_reloc)? else {
|
|
log::warn!("Failed to find function symbol for extabindex entry");
|
|
continue;
|
|
};
|
|
let extab_func_name = extab_func.name()?;
|
|
let Some(extab) = relocation_symbol(file, extab_reloc)? else {
|
|
log::warn!("Failed to find extab symbol for extabindex entry");
|
|
continue;
|
|
};
|
|
|
|
let extab_start_addr = extab.address() - extab_section.address();
|
|
let extab_end_addr = extab_start_addr + extab.size();
|
|
|
|
// All relocations in the extab section are dtors
|
|
let mut dtors: Vec<ExtabSymbolRef> = vec![];
|
|
for (_, reloc) in extab_relocations.range(extab_start_addr..extab_end_addr) {
|
|
let Some(symbol) = relocation_symbol(file, reloc)? else {
|
|
log::warn!("Failed to find symbol for extab relocation");
|
|
continue;
|
|
};
|
|
dtors.push(make_symbol_ref(&symbol)?);
|
|
}
|
|
|
|
// Decode the extab data
|
|
let Some(extab_data) = extab_section.data_range(extab_start_addr, extab.size())? else {
|
|
log::warn!("Failed to get extab data for function {}", extab_func_name);
|
|
continue;
|
|
};
|
|
let data = match decode_extab(extab_data) {
|
|
Ok(decoded_data) => decoded_data,
|
|
Err(e) => {
|
|
log::warn!(
|
|
"Exception table decoding failed for function {}, reason: {}",
|
|
extab_func_name,
|
|
e.to_string()
|
|
);
|
|
return Ok(None);
|
|
}
|
|
};
|
|
|
|
//Add the new entry to the list
|
|
result.insert(extab_func.index().0 - 1, ExceptionInfo {
|
|
eti_symbol: make_symbol_ref(&extabindex)?,
|
|
etb_symbol: make_symbol_ref(&extab)?,
|
|
data,
|
|
dtors,
|
|
});
|
|
}
|
|
|
|
Ok(Some(result))
|
|
}
|
|
|
|
fn relocation_symbol<'data, 'file>(
|
|
file: &'file object::File<'data>,
|
|
relocation: &object::Relocation,
|
|
) -> Result<Option<object::Symbol<'data, 'file>>> {
|
|
let addend = relocation.addend();
|
|
match relocation.target() {
|
|
object::RelocationTarget::Symbol(idx) => {
|
|
ensure!(addend == 0, "Symbol relocations must have zero addend");
|
|
Ok(Some(file.symbol_by_index(idx)?))
|
|
}
|
|
object::RelocationTarget::Section(idx) => {
|
|
ensure!(addend >= 0, "Section relocations must have non-negative addend");
|
|
let addend = addend as u64;
|
|
Ok(file
|
|
.symbols()
|
|
.find(|symbol| symbol.section_index() == Some(idx) && symbol.address() == addend))
|
|
}
|
|
target => bail!("Unsupported relocation target: {target:?}"),
|
|
}
|
|
}
|
|
|
|
fn make_symbol_ref(symbol: &object::Symbol) -> Result<ExtabSymbolRef> {
|
|
let name = symbol.name()?.to_string();
|
|
let demangled_name = cwdemangle::demangle(&name, &cwdemangle::DemangleOptions::default());
|
|
Ok(ExtabSymbolRef { original_index: symbol.index().0 - 1, name, demangled_name })
|
|
}
|
|
|
|
fn guess_data_type_from_load_store_inst_op(inst_op: ppc750cl::Opcode) -> Option<DataType> {
|
|
use ppc750cl::Opcode;
|
|
match inst_op {
|
|
Opcode::Lbz | Opcode::Lbzu | Opcode::Lbzux | Opcode::Lbzx => Some(DataType::Int8),
|
|
Opcode::Lhz | Opcode::Lhzu | Opcode::Lhzux | Opcode::Lhzx => Some(DataType::Int16),
|
|
Opcode::Lha | Opcode::Lhau | Opcode::Lhaux | Opcode::Lhax => Some(DataType::Int16),
|
|
Opcode::Lwz | Opcode::Lwzu | Opcode::Lwzux | Opcode::Lwzx => Some(DataType::Int32),
|
|
Opcode::Lfs | Opcode::Lfsu | Opcode::Lfsux | Opcode::Lfsx => Some(DataType::Float),
|
|
Opcode::Lfd | Opcode::Lfdu | Opcode::Lfdux | Opcode::Lfdx => Some(DataType::Double),
|
|
|
|
Opcode::Stb | Opcode::Stbu | Opcode::Stbux | Opcode::Stbx => Some(DataType::Int8),
|
|
Opcode::Sth | Opcode::Sthu | Opcode::Sthux | Opcode::Sthx => Some(DataType::Int16),
|
|
Opcode::Stw | Opcode::Stwu | Opcode::Stwux | Opcode::Stwx => Some(DataType::Int32),
|
|
Opcode::Stfs | Opcode::Stfsu | Opcode::Stfsux | Opcode::Stfsx => Some(DataType::Float),
|
|
Opcode::Stfd | Opcode::Stfdu | Opcode::Stfdux | Opcode::Stfdx => Some(DataType::Double),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
struct PoolReference {
|
|
addr_src_gpr: ppc750cl::GPR,
|
|
addr_offset: i16,
|
|
addr_dst_gpr: Option<ppc750cl::GPR>,
|
|
}
|
|
|
|
// Given an instruction, check if it could be accessing pooled data at the address in a register.
|
|
// If so, return information pertaining to where the instruction is getting that address from and
|
|
// what it's doing with the address (e.g. copying it into another register, adding an offset, etc).
|
|
fn get_pool_reference_for_inst(
|
|
opcode: ppc750cl::Opcode,
|
|
simplified: &ppc750cl::ParsedIns,
|
|
) -> Option<PoolReference> {
|
|
use ppc750cl::{Argument, Opcode};
|
|
let args = &simplified.args;
|
|
if guess_data_type_from_load_store_inst_op(opcode).is_some() {
|
|
match (args[1], args[2]) {
|
|
(Argument::Offset(offset), Argument::GPR(addr_src_gpr)) => {
|
|
// e.g. lwz. Immediate offset.
|
|
Some(PoolReference { addr_src_gpr, addr_offset: offset.0, addr_dst_gpr: None })
|
|
}
|
|
(Argument::GPR(addr_src_gpr), Argument::GPR(_offset_gpr)) => {
|
|
// e.g. lwzx. The offset is in a register and was likely calculated from an index.
|
|
// Treat the offset as being 0 in this case to show the first element of the array.
|
|
// It may be possible to show all elements by figuring out the stride of the array
|
|
// from the calculations performed on the index before it's put into offset_gpr, but
|
|
// this would be much more complicated, so it's not currently done.
|
|
Some(PoolReference { addr_src_gpr, addr_offset: 0, addr_dst_gpr: None })
|
|
}
|
|
_ => None,
|
|
}
|
|
} else {
|
|
// If it's not a load/store instruction, there's two more possibilities we need to handle.
|
|
// 1. It could be loading a pointer to a string.
|
|
// 2. It could be moving the relocation address plus an offset into a different register to
|
|
// load from later.
|
|
// If either of these match, we also want to return the destination register that the
|
|
// address is being copied into so that we can detect any future references to that new
|
|
// register as well.
|
|
match (opcode, args[0], args[1], args[2]) {
|
|
(
|
|
Opcode::Addi,
|
|
Argument::GPR(addr_dst_gpr),
|
|
Argument::GPR(addr_src_gpr),
|
|
Argument::Simm(simm),
|
|
) => Some(PoolReference {
|
|
addr_src_gpr,
|
|
addr_offset: simm.0,
|
|
addr_dst_gpr: Some(addr_dst_gpr),
|
|
}),
|
|
(
|
|
// `mr` or `mr.`
|
|
Opcode::Or,
|
|
Argument::GPR(addr_dst_gpr),
|
|
Argument::GPR(addr_src_gpr),
|
|
Argument::None,
|
|
) => Some(PoolReference {
|
|
addr_src_gpr,
|
|
addr_offset: 0,
|
|
addr_dst_gpr: Some(addr_dst_gpr),
|
|
}),
|
|
(
|
|
Opcode::Add,
|
|
Argument::GPR(addr_dst_gpr),
|
|
Argument::GPR(addr_src_gpr),
|
|
Argument::GPR(_offset_gpr),
|
|
) => Some(PoolReference {
|
|
addr_src_gpr,
|
|
addr_offset: 0,
|
|
addr_dst_gpr: Some(addr_dst_gpr),
|
|
}),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
// Remove the relocation we're keeping track of in a particular register when an instruction reuses
|
|
// that register to hold some other value, unrelated to pool relocation addresses.
|
|
fn clear_overwritten_gprs(ins: ppc750cl::Ins, gpr_pool_relocs: &mut BTreeMap<u8, Relocation>) {
|
|
use ppc750cl::{Argument, Arguments, Opcode};
|
|
let mut def_args = Arguments::default();
|
|
ins.parse_defs(&mut def_args);
|
|
for arg in def_args {
|
|
if let Argument::GPR(gpr) = arg {
|
|
if ins.op == Opcode::Lmw {
|
|
// `lmw` overwrites all registers from rd to r31.
|
|
// ppc750cl only returns rd itself, so we manually clear the rest of them.
|
|
for reg in gpr.0..31 {
|
|
gpr_pool_relocs.remove(®);
|
|
}
|
|
break;
|
|
}
|
|
gpr_pool_relocs.remove(&gpr.0);
|
|
}
|
|
}
|
|
}
|
|
|
|
// We create a fake relocation for an instruction, vaguely simulating what the actual relocation
|
|
// might have looked like if it wasn't pooled. This is so minimal changes are needed to display
|
|
// pooled accesses vs non-pooled accesses. We set the relocation type to R_PPC_NONE to indicate that
|
|
// there isn't really a relocation here, as copying the pool relocation's type wouldn't make sense.
|
|
// Also, if this instruction is accessing the middle of a symbol instead of the start, we add an
|
|
// addend to indicate that.
|
|
fn make_fake_pool_reloc(
|
|
offset: i16,
|
|
cur_addr: u32,
|
|
pool_reloc: &Relocation,
|
|
symbols: &[Symbol],
|
|
) -> Option<Relocation> {
|
|
let pool_reloc = resolve_relocation(symbols, pool_reloc);
|
|
let offset_from_pool = pool_reloc.relocation.addend + offset as i64;
|
|
let target_address = pool_reloc.symbol.address.checked_add_signed(offset_from_pool)?;
|
|
let target_symbol;
|
|
let addend;
|
|
if let Some(section_index) = pool_reloc.symbol.section {
|
|
// Find the exact data symbol within the pool being accessed here based on the address.
|
|
target_symbol = symbols.iter().position(|s| {
|
|
s.section == Some(section_index)
|
|
&& s.size > 0
|
|
&& (s.address..s.address + s.size).contains(&target_address)
|
|
})?;
|
|
addend = target_address.checked_sub(symbols[target_symbol].address)? as i64;
|
|
} else {
|
|
// If the target symbol is in a different object (extern), we simply copy the pool
|
|
// relocation's target. This is because it's not possible to locate the actual symbol if
|
|
// it's extern. And doing that for external symbols would also be unnecessary, because when
|
|
// the compiler generates an instruction that accesses an external "pool" plus some offset,
|
|
// that won't be a normal pool that contains other symbols within it that we want to
|
|
// display. It will be something like a vtable for a class with multiple inheritance (for
|
|
// example, dCcD_Cyl in The Wind Waker). So just showing that vtable symbol plus an addend
|
|
// to represent the offset into it works fine in this case.
|
|
target_symbol = pool_reloc.relocation.target_symbol;
|
|
addend = offset_from_pool;
|
|
}
|
|
Some(Relocation {
|
|
flags: RelocationFlags::Elf(elf::R_PPC_NONE),
|
|
address: cur_addr as u64,
|
|
target_symbol,
|
|
addend,
|
|
})
|
|
}
|
|
|
|
// Searches through all instructions in a function, determining which registers have the addresses
|
|
// of pooled data relocations in them, finding which instructions load data from those addresses,
|
|
// and returns a Vec of "fake pool relocations" that simulate what a relocation for that instruction
|
|
// would look like if data hadn't been pooled.
|
|
// This method tries to follow the function's proper control flow. It keeps track of a queue of
|
|
// states it hasn't traversed yet, where each state holds an instruction address and a HashMap of
|
|
// which registers hold which pool relocations at that point.
|
|
// When a conditional or unconditional branch is encountered, the destination of the branch is added
|
|
// to the queue. Conditional branches will traverse both the path where the branch is taken and the
|
|
// one where it's not. Unconditional branches only follow the branch, ignoring any code immediately
|
|
// after the branch instruction.
|
|
// Limitations: This method does not currently read switch statement jump tables.
|
|
// Instead, we guess that any parts of a function we missed were switch cases, and traverse them as
|
|
// if the last `bctr` before that address had branched there. This should be fairly accurate in
|
|
// practice - in testing the only instructions it seems to miss are double branches that the
|
|
// compiler generates in error which can never be reached during normal execution anyway.
|
|
// It should be possible to implement jump tables properly by reading them out of .data. But this
|
|
// will require keeping track of what value is loaded into each register so we can retrieve the jump
|
|
// table symbol when we encounter a `bctr`.
|
|
fn generate_fake_pool_relocations_for_function(
|
|
func_address: u64,
|
|
code: &[u8],
|
|
relocations: &[Relocation],
|
|
symbols: &[Symbol],
|
|
) -> Vec<Relocation> {
|
|
use ppc750cl::{Argument, InsIter, Opcode};
|
|
let mut visited_ins_addrs = BTreeSet::new();
|
|
let mut pool_reloc_for_addr = BTreeMap::new();
|
|
let mut ins_iters_with_gpr_state =
|
|
vec![(InsIter::new(code, func_address as u32), BTreeMap::new())];
|
|
let mut gpr_state_at_bctr = BTreeMap::new();
|
|
while let Some((ins_iter, mut gpr_pool_relocs)) = ins_iters_with_gpr_state.pop() {
|
|
for (cur_addr, ins) in ins_iter {
|
|
if visited_ins_addrs.contains(&cur_addr) {
|
|
// Avoid getting stuck in an infinite loop when following looping branches.
|
|
break;
|
|
}
|
|
visited_ins_addrs.insert(cur_addr);
|
|
|
|
let simplified = ins.simplified();
|
|
|
|
// First handle traversing the function's control flow.
|
|
let mut branch_dest = None;
|
|
for arg in simplified.args_iter() {
|
|
if let Argument::BranchDest(dest) = arg {
|
|
let dest = cur_addr.wrapping_add_signed(dest.0);
|
|
branch_dest = Some(dest);
|
|
break;
|
|
}
|
|
}
|
|
if let Some(branch_dest) = branch_dest {
|
|
if branch_dest >= func_address as u32
|
|
&& (branch_dest - func_address as u32) < code.len() as u32
|
|
{
|
|
let dest_offset_into_func = branch_dest - func_address as u32;
|
|
let dest_code_slice = &code[dest_offset_into_func as usize..];
|
|
match ins.op {
|
|
Opcode::Bc => {
|
|
// Conditional branch.
|
|
// Add the branch destination to the queue to do later.
|
|
ins_iters_with_gpr_state.push((
|
|
InsIter::new(dest_code_slice, branch_dest),
|
|
gpr_pool_relocs.clone(),
|
|
));
|
|
// Then continue on with the current iterator.
|
|
}
|
|
Opcode::B => {
|
|
if simplified.mnemonic != "bl" {
|
|
// Unconditional branch.
|
|
// Add the branch destination to the queue.
|
|
ins_iters_with_gpr_state.push((
|
|
InsIter::new(dest_code_slice, branch_dest),
|
|
gpr_pool_relocs.clone(),
|
|
));
|
|
// Break out of the current iterator so we can do the newly added one.
|
|
break;
|
|
}
|
|
}
|
|
_ => unreachable!(),
|
|
}
|
|
}
|
|
}
|
|
if let Opcode::Bcctr = ins.op {
|
|
if simplified.mnemonic == "bctr" {
|
|
// Unconditional branch to count register.
|
|
// Likely a jump table.
|
|
gpr_state_at_bctr.insert(cur_addr, gpr_pool_relocs.clone());
|
|
}
|
|
}
|
|
|
|
// Then handle keeping track of which GPR contains which pool relocation.
|
|
let reloc = relocations.iter().find(|r| (r.address as u32 & !3) == cur_addr);
|
|
if let Some(reloc) = reloc {
|
|
// This instruction has a real relocation, so it may be a pool load we want to keep
|
|
// track of.
|
|
let args = &simplified.args;
|
|
match (ins.op, args[0], args[1], args[2]) {
|
|
(
|
|
// `lis` + `addi`
|
|
Opcode::Addi,
|
|
Argument::GPR(addr_dst_gpr),
|
|
Argument::GPR(_addr_src_gpr),
|
|
Argument::Simm(_simm),
|
|
) => {
|
|
gpr_pool_relocs.insert(addr_dst_gpr.0, reloc.clone());
|
|
}
|
|
(
|
|
// `lis` + `ori`
|
|
Opcode::Ori,
|
|
Argument::GPR(addr_dst_gpr),
|
|
Argument::GPR(_addr_src_gpr),
|
|
Argument::Uimm(_uimm),
|
|
) => {
|
|
gpr_pool_relocs.insert(addr_dst_gpr.0, reloc.clone());
|
|
}
|
|
(Opcode::B, _, _, _) => {
|
|
if simplified.mnemonic == "bl" {
|
|
// When encountering a function call, clear any active pool relocations from
|
|
// the volatile registers (r0, r3-r12), but not the nonvolatile registers.
|
|
gpr_pool_relocs.remove(&0);
|
|
for gpr in 3..12 {
|
|
gpr_pool_relocs.remove(&gpr);
|
|
}
|
|
}
|
|
}
|
|
_ => {
|
|
clear_overwritten_gprs(ins, &mut gpr_pool_relocs);
|
|
}
|
|
}
|
|
} else if let Some(pool_ref) = get_pool_reference_for_inst(ins.op, &simplified) {
|
|
// This instruction doesn't have a real relocation, so it may be a reference to one of
|
|
// the already-loaded pools.
|
|
if let Some(pool_reloc) = gpr_pool_relocs.get(&pool_ref.addr_src_gpr.0) {
|
|
if let Some(fake_pool_reloc) =
|
|
make_fake_pool_reloc(pool_ref.addr_offset, cur_addr, pool_reloc, symbols)
|
|
{
|
|
pool_reloc_for_addr.insert(cur_addr, fake_pool_reloc);
|
|
}
|
|
if let Some(addr_dst_gpr) = pool_ref.addr_dst_gpr {
|
|
// If the address of the pool relocation got copied into another register, we
|
|
// need to keep track of it in that register too as future instructions may
|
|
// reference the symbol indirectly via this new register, instead of the
|
|
// register the symbol's address was originally loaded into.
|
|
// For example, the start of the function might `lis` + `addi` the start of the
|
|
// ...data pool into r25, and then later the start of a loop will `addi` r25
|
|
// with the offset within the .data section of an array variable into r21.
|
|
// Then the body of the loop will `lwzx` one of the array elements from r21.
|
|
let mut new_reloc = pool_reloc.clone();
|
|
new_reloc.addend += pool_ref.addr_offset as i64;
|
|
gpr_pool_relocs.insert(addr_dst_gpr.0, new_reloc);
|
|
} else {
|
|
clear_overwritten_gprs(ins, &mut gpr_pool_relocs);
|
|
}
|
|
} else {
|
|
clear_overwritten_gprs(ins, &mut gpr_pool_relocs);
|
|
}
|
|
} else {
|
|
clear_overwritten_gprs(ins, &mut gpr_pool_relocs);
|
|
}
|
|
}
|
|
|
|
// Finally, if we're about to finish the outer loop and don't have any more control flow to
|
|
// follow, we check if there are any instruction addresses in this function that we missed.
|
|
// If so, and if there were any `bctr` instructions before those points in this function,
|
|
// then we try to traverse those missing spots as switch cases.
|
|
if ins_iters_with_gpr_state.is_empty() {
|
|
let unseen_addrs = (func_address as u32..func_address as u32 + code.len() as u32)
|
|
.step_by(4)
|
|
.filter(|addr| !visited_ins_addrs.contains(addr));
|
|
for unseen_addr in unseen_addrs {
|
|
let prev_bctr_gpr_state = gpr_state_at_bctr
|
|
.iter()
|
|
.filter(|&(&addr, _)| addr < unseen_addr)
|
|
.min_by_key(|&(&addr, _)| addr)
|
|
.map(|(_, gpr_state)| gpr_state);
|
|
if let Some(gpr_pool_relocs) = prev_bctr_gpr_state {
|
|
let dest_offset_into_func = unseen_addr - func_address as u32;
|
|
let dest_code_slice = &code[dest_offset_into_func as usize..];
|
|
ins_iters_with_gpr_state.push((
|
|
InsIter::new(dest_code_slice, unseen_addr),
|
|
gpr_pool_relocs.clone(),
|
|
));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pool_reloc_for_addr.values().cloned().collect()
|
|
}
|