我正在开发一个项目,在其中使用clang生成一些LLVM IR,然后在我的主机应用程序中进行即时编译和运行。JIT代码调用主机应用程序中的一些函数,这些函数可能会引发异常。我希望异常通过JIT代码抛出并在主机应用程序中捕获回来。据我所知,LLVM应该可以做到这一点,但不幸的是,我的测试应用程序总是崩溃并显示“terminate called after throwing an instance of 'int'”错误。让我举个简单的例子。
我使用clang 3.5将以下简单程序编译为LLVM IR:
extern void test() ;
extern "C" void exec(void*) {
test();
}
随着
./clang -O0 -S -emit-llvm test.cpp -c
结果是test.ll
; ModuleID = 'test.cpp'
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: uwtable
define void @exec(i8*) #0 {
%2 = alloca i8*, align 8
store i8* %0, i8** %2, align 8
call void @_Z4testv()
ret void
}
declare void @_Z4testv() #1
attributes #0 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.ident = !{!0}
!0 = metadata !{metadata !"clang version 3.5.0 (224841)"}
我的主机应用程序长这样:
static void test() {
throw 1;
}
int main(int, const char **) {
llvm::InitializeNativeTarget();
llvm::InitializeNativeTargetAsmPrinter();
llvm::InitializeNativeTargetAsmParser();
llvm::LLVMContext &Context = llvm::getGlobalContext();
llvm::SMDiagnostic Err;
llvm::Module *Mod = llvm::ParseIRFile("test.ll", Err, Context);
llvm::ExecutionEngine* m_EE = llvm::EngineBuilder(Mod)
.setEngineKind(llvm::EngineKind::JIT)
.create();
llvm::Function* f = Mod->getFunction("_Z4testv");
m_EE->addGlobalMapping(f, reinterpret_cast<void*>(test));
f = Mod->getFunction("exec");
void* poi = m_EE->getPointerToFunction(f);
void (*exec)(void*) = reinterpret_cast<void (*)(void*)>(poi);
try {
exec(NULL);
} catch (...) {
std::cout << "catched exception" << std::endl;
}
return 0;
}
我使用CMake编译的LLVM 3.5版本。在编译时,我将LLVM_ENABLE_EH和LLVM_ENABLE_RTTI参数设置为ON。请问我是否在编译LLVM时遗漏了什么或者我的主机应用程序代码有问题?
谢谢!