7
我試圖爲LLVM 3.2優化器構建一個通行證,我需要一個支配樹。這應該很容易通過從PassManager請求DominatorTree
分析結果,但即使這個簡單的示例崩潰。LLVM通過getAnalysis通過segfaults <DominatorTree>()
我在做什麼錯?
namespace {
struct Mypass : public FunctionPass {
static char ID;
Mypass() : FunctionPass(ID) { }
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTree>();
}
virtual bool runOnFunction(Function &F) {
DominatorTree& DT = getAnalysis<DominatorTree>(F);
return false;
}
};
}
char Mypass::ID = 0;
static RegisterPass<Mypass> X("mypass", "My test analysis", true, true);
時調用
opt --load mypass.so -mypass --debug-pass=Structure test.bc
立即出現segfaults與
Pass Arguments: -targetlibinfo -datalayout -domtree -mypass -preverify -domtree -verify
Target Library Information
Data Layout
ModulePass Manager
FunctionPass Manager
Dominator Tree Construction
My test analysis
Preliminary module verification
Dominator Tree Construction
Module Verifier
0 libLLVM-3.2.so.1 0x00007f2d8172a1df
1 libLLVM-3.2.so.1 0x00007f2d8172a649
2 libpthread.so.0 0x00007f2d80842bd0
3 mypass.so 0x00007f2d7f63deb9 llvm::DominatorTree& llvm::Pass::getAnalysisID<llvm::DominatorTree>(void const*, llvm::Function&) + 217
4 mypass.so 0x00007f2d7f63ddce llvm::DominatorTree& llvm::Pass::getAnalysis<llvm::DominatorTree>(llvm::Function&) + 94
5 mypass.so 0x00007f2d7f63dc38
6 libLLVM-3.2.so.1 0x00007f2d811e0e3f llvm::FPPassManager::runOnFunction(llvm::Function&) + 575
7 libLLVM-3.2.so.1 0x00007f2d811e0e83 llvm::FPPassManager::runOnModule(llvm::Module&) + 51
8 libLLVM-3.2.so.1 0x00007f2d811e0ba4 llvm::MPPassManager::runOnModule(llvm::Module&) + 484
9 libLLVM-3.2.so.1 0x00007f2d811e44bb llvm::PassManagerImpl::run(llvm::Module&) + 107
10 opt 0x000000000040d606 main + 4230
11 libc.so.6 0x00007f2d80189ea5 __libc_start_main + 245
12 opt 0x000000000040db41
Stack dump:
0. Program arguments: opt --load mypass.so -mypass --debug-pass=Structure
1. Running pass 'Function Pass Manager' on module '<stdin>'.
2. Running pass 'My test analysis' on function '@const_expr'
Segmentation fault (core dumped)
是的,這似乎工作!但我仍然感到困惑,因爲http://llvm.org/docs/WritingAnLLVMPass.html#the-getanalysis-and-getanalysisifavailable-方法中的示例使用參數調用方法... – 2013-02-12 19:32:16
正如本教程所述:「A __module級別pass__可以使用__function__使用此接口的級別分析信息「;你的pass是一個'FunctionPass',參數化方法是一個'ModulePass',因爲dominatorTree是一個功能相關的分析,你可以直接在你的FunctionPass中使用它。 – 2013-02-13 02:49:51