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ignoring ifuncs on fixed map LTO

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This commit is contained in:
van Hauser
2020-08-11 01:31:44 +02:00
parent 1e38c10efb
commit 432638404f
1 changed files with 38 additions and 11 deletions
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47
llvm_mode/afl-llvm-lto-instrumentation.so.cc
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@ -219,21 +219,30 @@ bool AFLLTOPass::runOnModule(Module &M) {
*/
if (map_addr)
std::vector<std::string> module_block_list;
if (map_addr) {
for (GlobalIFunc &IF : M.ifuncs()) {
// No clue how to follow these up and find the resolver function.
// If we would know that resolver function name we could just skip
// instrumenting it and everything would be fine :-(
// StringRef ifunc_name = IF.getName();
// Constant *r = IF.getResolver();
FATAL(
"Target uses ifunc attribute for %s, fixed map cannot be used, "
"remove AFL_LLVM_MAP_ADDR",
IF.getName().str().c_str());
StringRef ifunc_name = IF.getName();
Constant *r = IF.getResolver();
StringRef r_name = cast<Function>(r->getOperand(0))->getName();
if (!be_quiet)
fprintf(stderr, "Found an ifunc with name %s that points to resolver function %s, we cannot instrument this, putting it into a block list.\n",
ifunc_name.str().c_str(), r_name.str().c_str());
module_block_list.push_back(r_name.str());
}
// next up: ctors run before __afl_init()
// TODO
}
/* Instrument all the things! */
int inst_blocks = 0;
@ -250,6 +259,24 @@ bool AFLLTOPass::runOnModule(Module &M) {
if (F.size() < function_minimum_size) continue;
if (isIgnoreFunction(&F)) continue;
if (module_block_list.size()) {
for (auto bname : module_block_list) {
std::string fname = F.getName().str();
if (fname.compare(bname) == 0) {
if (!be_quiet)
WARNF("Skipping instrumentation of ifunc resolver function %s",
fname.c_str());
}
}
}
// the instrument file list check
AttributeList Attrs = F.getAttributes();
if (Attrs.hasAttribute(-1, StringRef("skipinstrument"))) {