[llvm] Call the LLVM Jit from c program-白红宇

[llvm] Call the LLVM Jit from c program

阅读量：4982 次

发布时间：2019-06-12

本文共 2055 字，大约阅读时间需要 6 分钟。

stackoverflow: http://stackoverflow.com/questions/1838304/call-the-llvm-jit-from-c-program

Another trial under llvm 3.2;

In prepared IR "tst.ll", code:

; ModuleID = 'tst.bc'                                                 define i32 @add1(i32 %AnArg) {     EntryBlock:                          %0 = add i32 1, %AnArg             ret i32 %0                       }                                                                     define i32 @foo() {                EntryBlock:                          %0 = tail call i32 @add1(i32 10)   ret i32 %0                       }

run " llvm-as tst.ll " to create the asm file tst.bc

then the caller programe:

#include 
     
                                                                               #include 
      
                                                                                #include 
       
                                                                                                                                                                         #include 
        
                                                                      #include 
         
                                                              #include 
          
            #include 
           
             #include 
            
              #include 
             
               #include 
              
                #include 
               
                 using namespace std; using namespace llvm; int main() { InitializeNativeTarget(); llvm_start_multithreaded(); LLVMContext context; string error; OwningPtr
                
                  file_buffer; MemoryBuffer::getFile("tst.bc", file_buffer); Module *m = ParseBitcodeFile(file_buffer.get(), context, &error); ExecutionEngine *ee = ExecutionEngine::create(m); Function* func = ee->FindFunctionNamed("foo"); typedef int (*PFN)(); PFN pfn = reinterpret_cast
                 
                  (ee->getPointerToFunction(func)); int x = pfn(); cout << "~~~ " << x << "\n"; delete ee; }

In the above example, IR codes are load from a file. In more dymanic usage, we could construct the IR code as a string according to input "query" type. Then compile the IR to bitcode on the fly.

转载于:https://www.cnblogs.com/luweiseu/p/3161146.html

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