llvm-project/llvm/examples/OrcV2Examples/OrcV2CBindingsRemovableCode/OrcV2CBindingsRemovableCode.c

177 lines
5.4 KiB
C

//===-------- BasicOrcV2CBindings.c - Basic OrcV2 C Bindings Demo ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm-c/Core.h"
#include "llvm-c/Error.h"
#include "llvm-c/Initialization.h"
#include "llvm-c/LLJIT.h"
#include "llvm-c/Support.h"
#include "llvm-c/Target.h"
#include <stdio.h>
int handleError(LLVMErrorRef Err) {
char *ErrMsg = LLVMGetErrorMessage(Err);
fprintf(stderr, "Error: %s\n", ErrMsg);
LLVMDisposeErrorMessage(ErrMsg);
return 1;
}
LLVMOrcThreadSafeModuleRef createDemoModule(void) {
// Create a new ThreadSafeContext and underlying LLVMContext.
LLVMOrcThreadSafeContextRef TSCtx = LLVMOrcCreateNewThreadSafeContext();
// Get a reference to the underlying LLVMContext.
LLVMContextRef Ctx = LLVMOrcThreadSafeContextGetContext(TSCtx);
// Create a new LLVM module.
LLVMModuleRef M = LLVMModuleCreateWithNameInContext("demo", Ctx);
// Add a "sum" function":
// - Create the function type and function instance.
LLVMTypeRef ParamTypes[] = {LLVMInt32Type(), LLVMInt32Type()};
LLVMTypeRef SumFunctionType =
LLVMFunctionType(LLVMInt32Type(), ParamTypes, 2, 0);
LLVMValueRef SumFunction = LLVMAddFunction(M, "sum", SumFunctionType);
// - Add a basic block to the function.
LLVMBasicBlockRef EntryBB = LLVMAppendBasicBlock(SumFunction, "entry");
// - Add an IR builder and point it at the end of the basic block.
LLVMBuilderRef Builder = LLVMCreateBuilder();
LLVMPositionBuilderAtEnd(Builder, EntryBB);
// - Get the two function arguments and use them co construct an "add"
// instruction.
LLVMValueRef SumArg0 = LLVMGetParam(SumFunction, 0);
LLVMValueRef SumArg1 = LLVMGetParam(SumFunction, 1);
LLVMValueRef Result = LLVMBuildAdd(Builder, SumArg0, SumArg1, "result");
// - Build the return instruction.
LLVMBuildRet(Builder, Result);
// Our demo module is now complete. Wrap it and our ThreadSafeContext in a
// ThreadSafeModule.
LLVMOrcThreadSafeModuleRef TSM = LLVMOrcCreateNewThreadSafeModule(M, TSCtx);
// Dispose of our local ThreadSafeContext value. The underlying LLVMContext
// will be kept alive by our ThreadSafeModule, TSM.
LLVMOrcDisposeThreadSafeContext(TSCtx);
// Return the result.
return TSM;
}
int main(int argc, char *argv[]) {
int MainResult = 0;
// Parse command line arguments and initialize LLVM Core.
LLVMParseCommandLineOptions(argc, (const char **)argv, "");
LLVMInitializeCore(LLVMGetGlobalPassRegistry());
// Initialize native target codegen and asm printer.
LLVMInitializeNativeTarget();
LLVMInitializeNativeAsmPrinter();
// Create the JIT instance.
LLVMOrcLLJITRef J;
{
LLVMErrorRef Err;
if ((Err = LLVMOrcCreateLLJIT(&J, 0))) {
MainResult = handleError(Err);
goto llvm_shutdown;
}
}
// Create our demo module.
LLVMOrcThreadSafeModuleRef TSM = createDemoModule();
LLVMOrcResourceTrackerRef RT;
// Add our demo module to the JIT.
{
LLVMOrcJITDylibRef MainJD = LLVMOrcLLJITGetMainJITDylib(J);
RT = LLVMOrcJITDylibCreateResourceTracker(MainJD);
LLVMErrorRef Err;
if ((Err = LLVMOrcLLJITAddLLVMIRModuleWithRT(J, RT, TSM))) {
// If adding the ThreadSafeModule fails then we need to clean it up
// ourselves. If adding it succeeds the JIT will manage the memory.
LLVMOrcDisposeThreadSafeModule(TSM);
MainResult = handleError(Err);
goto jit_cleanup;
}
}
// Look up the address of our demo entry point.
printf("Looking up before removal...\n");
LLVMOrcJITTargetAddress SumAddr;
{
LLVMErrorRef Err;
if ((Err = LLVMOrcLLJITLookup(J, &SumAddr, "sum"))) {
MainResult = handleError(Err);
goto jit_cleanup;
}
}
// If we made it here then everything succeeded. Execute our JIT'd code.
int32_t (*Sum)(int32_t, int32_t) = (int32_t(*)(int32_t, int32_t))SumAddr;
int32_t Result = Sum(1, 2);
// Print the result.
printf("1 + 2 = %i\n", Result);
// Remove the code.
{
LLVMErrorRef Err;
if ((Err = LLVMOrcResourceTrackerRemove(RT))) {
MainResult = handleError(Err);
goto jit_cleanup;
}
}
// Attempt a second lookup. Here we expect an error as the code and symbols
// should have been removed.
printf("Attempting to remove code / symbols...\n");
{
LLVMOrcJITTargetAddress ThrowAwayAddress;
LLVMErrorRef Err = LLVMOrcLLJITLookup(J, &ThrowAwayAddress, "sum");
if (Err) {
printf("Received error as expected:\n");
handleError(Err);
} else {
printf("Failure: Second lookup should have generated an error.\n");
MainResult = 1;
}
}
jit_cleanup:
// Destroy our JIT instance. This will clean up any memory that the JIT has
// taken ownership of. This operation is non-trivial (e.g. it may need to
// JIT static destructors) and may also fail. In that case we want to render
// the error to stderr, but not overwrite any existing return value.
printf("Releasing resource tracker...\n");
LLVMOrcReleaseResourceTracker(RT);
printf("Destroying LLJIT instance and exiting.\n");
{
LLVMErrorRef Err;
if ((Err = LLVMOrcDisposeLLJIT(J))) {
int NewFailureResult = handleError(Err);
if (MainResult == 0)
MainResult = NewFailureResult;
}
}
llvm_shutdown:
// Shut down LLVM.
LLVMShutdown();
return MainResult;
}