1 //===-------- BasicOrcV2CBindings.c - Basic OrcV2 C Bindings Demo ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm-c/Core.h"
10 #include "llvm-c/Error.h"
11 #include "llvm-c/Initialization.h"
12 #include "llvm-c/LLJIT.h"
13 #include "llvm-c/Support.h"
14 #include "llvm-c/Target.h"
15 
16 #include <stdio.h>
17 
18 int handleError(LLVMErrorRef Err) {
19   char *ErrMsg = LLVMGetErrorMessage(Err);
20   fprintf(stderr, "Error: %s\n", ErrMsg);
21   LLVMDisposeErrorMessage(ErrMsg);
22   return 1;
23 }
24 
25 LLVMOrcThreadSafeModuleRef createDemoModule() {
26   // Create a new ThreadSafeContext and underlying LLVMContext.
27   LLVMOrcThreadSafeContextRef TSCtx = LLVMOrcCreateNewThreadSafeContext();
28 
29   // Get a reference to the underlying LLVMContext.
30   LLVMContextRef Ctx = LLVMOrcThreadSafeContextGetContext(TSCtx);
31 
32   // Create a new LLVM module.
33   LLVMModuleRef M = LLVMModuleCreateWithNameInContext("demo", Ctx);
34 
35   // Add a "sum" function":
36   //  - Create the function type and function instance.
37   LLVMTypeRef ParamTypes[] = {LLVMInt32Type(), LLVMInt32Type()};
38   LLVMTypeRef SumFunctionType =
39       LLVMFunctionType(LLVMInt32Type(), ParamTypes, 2, 0);
40   LLVMValueRef SumFunction = LLVMAddFunction(M, "sum", SumFunctionType);
41 
42   //  - Add a basic block to the function.
43   LLVMBasicBlockRef EntryBB = LLVMAppendBasicBlock(SumFunction, "entry");
44 
45   //  - Add an IR builder and point it at the end of the basic block.
46   LLVMBuilderRef Builder = LLVMCreateBuilder();
47   LLVMPositionBuilderAtEnd(Builder, EntryBB);
48 
49   //  - Get the two function arguments and use them co construct an "add"
50   //    instruction.
51   LLVMValueRef SumArg0 = LLVMGetParam(SumFunction, 0);
52   LLVMValueRef SumArg1 = LLVMGetParam(SumFunction, 1);
53   LLVMValueRef Result = LLVMBuildAdd(Builder, SumArg0, SumArg1, "result");
54 
55   //  - Build the return instruction.
56   LLVMBuildRet(Builder, Result);
57 
58   // Our demo module is now complete. Wrap it and our ThreadSafeContext in a
59   // ThreadSafeModule.
60   LLVMOrcThreadSafeModuleRef TSM = LLVMOrcCreateNewThreadSafeModule(M, TSCtx);
61 
62   // Dispose of our local ThreadSafeContext value. The underlying LLVMContext
63   // will be kept alive by our ThreadSafeModule, TSM.
64   LLVMOrcDisposeThreadSafeContext(TSCtx);
65 
66   // Return the result.
67   return TSM;
68 }
69 
70 int main(int argc, char *argv[]) {
71 
72   int MainResult = 0;
73 
74   // Parse command line arguments and initialize LLVM Core.
75   LLVMParseCommandLineOptions(argc, (const char **)argv, "");
76   LLVMInitializeCore(LLVMGetGlobalPassRegistry());
77 
78   // Initialize native target codegen and asm printer.
79   LLVMInitializeNativeTarget();
80   LLVMInitializeNativeAsmPrinter();
81 
82   // Create the JIT instance.
83   LLVMOrcLLJITRef J;
84   {
85     LLVMErrorRef Err;
86     if ((Err = LLVMOrcCreateLLJIT(&J, 0))) {
87       MainResult = handleError(Err);
88       goto llvm_shutdown;
89     }
90   }
91 
92   // Create our demo module.
93   LLVMOrcThreadSafeModuleRef TSM = createDemoModule();
94 
95   // Add our demo module to the JIT.
96   {
97     LLVMOrcJITDylibRef MainJD = LLVMOrcLLJITGetMainJITDylib(J);
98     LLVMErrorRef Err;
99     if ((Err = LLVMOrcLLJITAddLLVMIRModule(J, MainJD, TSM))) {
100       // If adding the ThreadSafeModule fails then we need to clean it up
101       // ourselves. If adding it succeeds the JIT will manage the memory.
102       LLVMOrcDisposeThreadSafeModule(TSM);
103       MainResult = handleError(Err);
104       goto jit_cleanup;
105     }
106   }
107 
108   // Look up the address of our demo entry point.
109   LLVMOrcJITTargetAddress SumAddr;
110   {
111     LLVMErrorRef Err;
112     if ((Err = LLVMOrcLLJITLookup(J, &SumAddr, "sum"))) {
113       MainResult = handleError(Err);
114       goto jit_cleanup;
115     }
116   }
117 
118   // If we made it here then everything succeeded. Execute our JIT'd code.
119   int32_t (*Sum)(int32_t, int32_t) = (int32_t(*)(int32_t, int32_t))SumAddr;
120   int32_t Result = Sum(1, 2);
121 
122   // Print the result.
123   printf("1 + 2 = %i\n", Result);
124 
125 jit_cleanup:
126   // Destroy our JIT instance. This will clean up any memory that the JIT has
127   // taken ownership of. This operation is non-trivial (e.g. it may need to
128   // JIT static destructors) and may also fail. In that case we want to render
129   // the error to stderr, but not overwrite any existing return value.
130   {
131     LLVMErrorRef Err;
132     if ((Err = LLVMOrcDisposeLLJIT(J))) {
133       int NewFailureResult = handleError(Err);
134       if (MainResult == 0)
135         MainResult = NewFailureResult;
136     }
137   }
138 
139 llvm_shutdown:
140   // Shut down LLVM.
141   LLVMShutdown();
142 
143   return MainResult;
144 }
145