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/LLJIT.h"
12 #include "llvm-c/Support.h"
13 #include "llvm-c/Target.h"
14
15 #include <stdio.h>
16
handleError(LLVMErrorRef Err)17 int handleError(LLVMErrorRef Err) {
18 char *ErrMsg = LLVMGetErrorMessage(Err);
19 fprintf(stderr, "Error: %s\n", ErrMsg);
20 LLVMDisposeErrorMessage(ErrMsg);
21 return 1;
22 }
23
createDemoModule(void)24 LLVMOrcThreadSafeModuleRef createDemoModule(void) {
25 // Create a new ThreadSafeContext and underlying LLVMContext.
26 LLVMOrcThreadSafeContextRef TSCtx = LLVMOrcCreateNewThreadSafeContext();
27
28 // Get a reference to the underlying LLVMContext.
29 LLVMContextRef Ctx = LLVMOrcThreadSafeContextGetContext(TSCtx);
30
31 // Create a new LLVM module.
32 LLVMModuleRef M = LLVMModuleCreateWithNameInContext("demo", Ctx);
33
34 // Add a "sum" function":
35 // - Create the function type and function instance.
36 LLVMTypeRef ParamTypes[] = {LLVMInt32Type(), LLVMInt32Type()};
37 LLVMTypeRef SumFunctionType =
38 LLVMFunctionType(LLVMInt32Type(), ParamTypes, 2, 0);
39 LLVMValueRef SumFunction = LLVMAddFunction(M, "sum", SumFunctionType);
40
41 // - Add a basic block to the function.
42 LLVMBasicBlockRef EntryBB = LLVMAppendBasicBlock(SumFunction, "entry");
43
44 // - Add an IR builder and point it at the end of the basic block.
45 LLVMBuilderRef Builder = LLVMCreateBuilder();
46 LLVMPositionBuilderAtEnd(Builder, EntryBB);
47
48 // - Get the two function arguments and use them co construct an "add"
49 // instruction.
50 LLVMValueRef SumArg0 = LLVMGetParam(SumFunction, 0);
51 LLVMValueRef SumArg1 = LLVMGetParam(SumFunction, 1);
52 LLVMValueRef Result = LLVMBuildAdd(Builder, SumArg0, SumArg1, "result");
53
54 // - Build the return instruction.
55 LLVMBuildRet(Builder, Result);
56
57 // - Free the builder.
58 LLVMDisposeBuilder(Builder);
59
60 // Our demo module is now complete. Wrap it and our ThreadSafeContext in a
61 // ThreadSafeModule.
62 LLVMOrcThreadSafeModuleRef TSM = LLVMOrcCreateNewThreadSafeModule(M, TSCtx);
63
64 // Dispose of our local ThreadSafeContext value. The underlying LLVMContext
65 // will be kept alive by our ThreadSafeModule, TSM.
66 LLVMOrcDisposeThreadSafeContext(TSCtx);
67
68 // Return the result.
69 return TSM;
70 }
71
main(int argc,const char * argv[])72 int main(int argc, const char *argv[]) {
73
74 int MainResult = 0;
75
76 // Parse command line arguments and initialize LLVM Core.
77 LLVMParseCommandLineOptions(argc, argv, "");
78
79 // Initialize native target codegen and asm printer.
80 LLVMInitializeNativeTarget();
81 LLVMInitializeNativeAsmPrinter();
82
83 // Create the JIT instance.
84 LLVMOrcLLJITRef J;
85 {
86 LLVMErrorRef Err;
87 if ((Err = LLVMOrcCreateLLJIT(&J, 0))) {
88 MainResult = handleError(Err);
89 goto llvm_shutdown;
90 }
91 }
92
93 // Create our demo module.
94 LLVMOrcThreadSafeModuleRef TSM = createDemoModule();
95 LLVMOrcResourceTrackerRef RT;
96
97 // Add our demo module to the JIT.
98 {
99 LLVMOrcJITDylibRef MainJD = LLVMOrcLLJITGetMainJITDylib(J);
100 RT = LLVMOrcJITDylibCreateResourceTracker(MainJD);
101 LLVMErrorRef Err;
102 if ((Err = LLVMOrcLLJITAddLLVMIRModuleWithRT(J, RT, TSM))) {
103 // If adding the ThreadSafeModule fails then we need to clean it up
104 // ourselves. If adding it succeeds the JIT will manage the memory.
105 LLVMOrcDisposeThreadSafeModule(TSM);
106 MainResult = handleError(Err);
107 goto jit_cleanup;
108 }
109 }
110
111 // Look up the address of our demo entry point.
112 printf("Looking up before removal...\n");
113 LLVMOrcJITTargetAddress SumAddr;
114 {
115 LLVMErrorRef Err;
116 if ((Err = LLVMOrcLLJITLookup(J, &SumAddr, "sum"))) {
117 MainResult = handleError(Err);
118 goto jit_cleanup;
119 }
120 }
121
122 // If we made it here then everything succeeded. Execute our JIT'd code.
123 int32_t (*Sum)(int32_t, int32_t) = (int32_t(*)(int32_t, int32_t))SumAddr;
124 int32_t Result = Sum(1, 2);
125
126 // Print the result.
127 printf("1 + 2 = %i\n", Result);
128
129 // Remove the code.
130 {
131 LLVMErrorRef Err;
132 if ((Err = LLVMOrcResourceTrackerRemove(RT))) {
133 MainResult = handleError(Err);
134 goto jit_cleanup;
135 }
136 }
137
138 // Attempt a second lookup. Here we expect an error as the code and symbols
139 // should have been removed.
140 printf("Attempting to remove code / symbols...\n");
141 {
142 LLVMOrcJITTargetAddress ThrowAwayAddress;
143 LLVMErrorRef Err = LLVMOrcLLJITLookup(J, &ThrowAwayAddress, "sum");
144 if (Err) {
145 printf("Received error as expected:\n");
146 handleError(Err);
147 } else {
148 printf("Failure: Second lookup should have generated an error.\n");
149 MainResult = 1;
150 }
151 }
152
153 jit_cleanup:
154 // Destroy our JIT instance. This will clean up any memory that the JIT has
155 // taken ownership of. This operation is non-trivial (e.g. it may need to
156 // JIT static destructors) and may also fail. In that case we want to render
157 // the error to stderr, but not overwrite any existing return value.
158
159 printf("Releasing resource tracker...\n");
160 LLVMOrcReleaseResourceTracker(RT);
161
162 printf("Destroying LLJIT instance and exiting.\n");
163 {
164 LLVMErrorRef Err;
165 if ((Err = LLVMOrcDisposeLLJIT(J))) {
166 int NewFailureResult = handleError(Err);
167 if (MainResult == 0)
168 MainResult = NewFailureResult;
169 }
170 }
171
172 llvm_shutdown:
173 // Shut down LLVM.
174 LLVMShutdown();
175
176 return MainResult;
177 }
178