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use std::collections::HashMap;
use crate::frontend::{
ao::Op,
BasicBlockPointer,
ChunkContent,
Elf,
FunctionPointer,
GlobalPointer,
HasId,
Pointer,
Relocation,
VAddr,
};
pub(crate) struct SymbolizerPass {
addr_map: HashMap<VAddr, Pointer>,
}
impl SymbolizerPass {
#[allow(clippy::new_without_default)]
pub(crate) fn new() -> Self {
Self {
addr_map: HashMap::new(),
}
}
fn resolve_address(&mut self, elf: &Elf, vaddr: VAddr) {
let mut pointer = None;
if self.addr_map.contains_key(&vaddr) {
return;
}
for section in elf.iter_sections() {
if !section.contains_address(vaddr) {
continue;
}
for symbol in section.iter_symbols() {
if !symbol.contains_address(vaddr) {
continue;
}
for chunk in symbol.iter_chunks() {
if !chunk.contains_address(vaddr) {
continue;
}
if chunk.pending().is_some() {
assert!(!section.perms().is_executable());
let offset = vaddr - chunk.vaddr();
assert!(pointer.is_none());
pointer = Some(Pointer::Global(GlobalPointer {
elf: elf.id(),
section: section.id(),
symbol: symbol.id(),
chunk: chunk.id(),
offset: offset as usize,
}));
} else {
match chunk.content() {
ChunkContent::Code(func) => {
let entry = func.cfg().entry();
for bb in func.cfg().iter_basic_blocks() {
if bb.vaddr() == Some(vaddr) {
assert!(pointer.is_none());
if bb.id() == entry {
pointer = Some(Pointer::Function(FunctionPointer {
elf: elf.id(),
section: section.id(),
symbol: symbol.id(),
chunk: chunk.id(),
}));
} else {
pointer = Some(Pointer::BasicBlock(BasicBlockPointer {
elf: elf.id(),
section: section.id(),
symbol: symbol.id(),
chunk: chunk.id(),
bb: bb.id(),
}));
}
}
}
},
ChunkContent::Data {
..
} => {
let offset = vaddr - chunk.vaddr();
assert!(pointer.is_none());
pointer = Some(Pointer::Global(GlobalPointer {
elf: elf.id(),
section: section.id(),
symbol: symbol.id(),
chunk: chunk.id(),
offset: offset as usize,
}));
},
ChunkContent::Pointer(_) => {
assert_eq!(vaddr, chunk.vaddr());
assert!(pointer.is_none());
pointer = Some(Pointer::Global(GlobalPointer {
elf: elf.id(),
section: section.id(),
symbol: symbol.id(),
chunk: chunk.id(),
offset: 0,
}));
},
}
}
}
}
}
if let Some(pointer) = pointer {
self.addr_map.insert(vaddr, pointer);
} else {
panic!("Unable to symbolize {:#x} in {}", vaddr, elf.path().display());
}
}
fn collect_addresses(&mut self, elf: &Elf) {
for section in elf.iter_sections() {
for symbol in section.iter_symbols() {
for chunk in symbol.iter_chunks() {
if let Some(reloc) = chunk.pending() {
match reloc {
Relocation::Offset(addr) => self.resolve_address(elf, *addr as VAddr),
_ => panic!("Encountered an unresolved symbol import in symbolizer pass"),
}
} else if let ChunkContent::Code(func) = chunk.content() {
for bb in func.cfg().iter_basic_blocks() {
for op in bb.ops() {
if let Op::LoadVirtAddr {
vaddr,
..
} = op
{
self.resolve_address(elf, *vaddr);
}
}
}
}
}
}
}
}
fn rewrite_addresses(&self, elf: &mut Elf) {
for section in elf.iter_sections_mut() {
for symbol in section.iter_symbols_mut() {
for chunk in symbol.iter_chunks_mut() {
if let Some(reloc) = chunk.pending() {
let pointer = match reloc {
Relocation::Offset(addr) => self.addr_map.get(&(*addr as VAddr)).unwrap().clone(),
_ => panic!("Encountered an unresolved symbol import in symbolizer pass"),
};
chunk.resolve(pointer);
} else if let ChunkContent::Code(func) = chunk.content_mut() {
for bb in func.cfg_mut().iter_basic_blocks_mut() {
bb.set_cursor(0);
while let Some(op) = bb.cursor_op() {
if let Op::LoadVirtAddr {
dst,
vaddr,
} = op
{
let pointer = self.addr_map.get(vaddr).unwrap().clone();
bb.replace_op(Op::LoadPointer {
dst: *dst,
pointer,
});
}
if !bb.move_cursor_forward() {
break;
}
}
}
}
}
}
}
}
fn check(&self, elf: &Elf) {
for section in elf.iter_sections() {
for symbol in section.iter_symbols() {
for chunk in symbol.iter_chunks() {
assert!(chunk.pending().is_none());
}
}
}
}
pub(crate) fn run(&mut self, elf: &mut Elf) -> Result<(), String> {
self.collect_addresses(elf);
self.rewrite_addresses(elf);
self.check(elf);
Ok(())
}
}