[llvm] 10d0bd4 - [C-API] Add example code to exercise new MCJIT-like-memory-manager API.
Lang Hames via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 16 19:15:16 PST 2022
Author: Wenzel Jakob
Date: 2022-12-17T14:15:07+11:00
New Revision: 10d0bd44ae15c8e9398a177c45b9c415ce813550
URL: https://github.com/llvm/llvm-project/commit/10d0bd44ae15c8e9398a177c45b9c415ce813550
DIFF: https://github.com/llvm/llvm-project/commit/10d0bd44ae15c8e9398a177c45b9c415ce813550.diff
LOG: [C-API] Add example code to exercise new MCJIT-like-memory-manager API.
This example shows how to use the newly added
LLVMOrcCreateRTDyldObjectLinkingLayerWithMCJITMemoryManagerLikeCallbacks API.
Added:
llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/CMakeLists.txt
llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/OrcV2CBindingsMCJITLikeMemoryManager.c
Modified:
llvm/examples/OrcV2Examples/CMakeLists.txt
Removed:
################################################################################
diff --git a/llvm/examples/OrcV2Examples/CMakeLists.txt b/llvm/examples/OrcV2Examples/CMakeLists.txt
index d4957c20f5ff1..af738e7bcb309 100644
--- a/llvm/examples/OrcV2Examples/CMakeLists.txt
+++ b/llvm/examples/OrcV2Examples/CMakeLists.txt
@@ -13,6 +13,7 @@ add_subdirectory(OrcV2CBindingsAddObjectFile)
add_subdirectory(OrcV2CBindingsBasicUsage)
add_subdirectory(OrcV2CBindingsDumpObjects)
add_subdirectory(OrcV2CBindingsIRTransforms)
+add_subdirectory(OrcV2CBindingsMCJITLikeMemoryManager)
add_subdirectory(OrcV2CBindingsReflectProcessSymbols)
add_subdirectory(OrcV2CBindingsRemovableCode)
add_subdirectory(OrcV2CBindingsLazy)
diff --git a/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/CMakeLists.txt b/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/CMakeLists.txt
new file mode 100644
index 0000000000000..4cdc2b114e9a5
--- /dev/null
+++ b/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/CMakeLists.txt
@@ -0,0 +1,15 @@
+set(LLVM_LINK_COMPONENTS
+ Core
+ ExecutionEngine
+ IRReader
+ JITLink
+ MC
+ OrcJIT
+ Support
+ Target
+ nativecodegen
+ )
+
+add_llvm_example(OrcV2CBindingsMCJITLikeMemoryManager
+ OrcV2CBindingsMCJITLikeMemoryManager.c
+ )
diff --git a/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/OrcV2CBindingsMCJITLikeMemoryManager.c b/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/OrcV2CBindingsMCJITLikeMemoryManager.c
new file mode 100644
index 0000000000000..1e80ae091ff20
--- /dev/null
+++ b/llvm/examples/OrcV2Examples/OrcV2CBindingsMCJITLikeMemoryManager/OrcV2CBindingsMCJITLikeMemoryManager.c
@@ -0,0 +1,277 @@
+//=== OrcV2CBindingsMemoryManager.c - OrcV2 Memory Manager 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This demo illustrates the C-API bindings for custom memory managers in
+// ORCv2. They are used here to place generated code into manually allocated
+// buffers that are subsequently marked as executable.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-c/Core.h"
+#include "llvm-c/Error.h"
+#include "llvm-c/Initialization.h"
+#include "llvm-c/LLJIT.h"
+#include "llvm-c/OrcEE.h"
+#include "llvm-c/Support.h"
+#include "llvm-c/Target.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#include <sys/mman.h>
+#endif
+
+struct Section {
+ void *Ptr;
+ size_t Size;
+ LLVMBool IsCode;
+};
+
+char CtxCtxPlaceholder;
+char CtxPlaceholder;
+
+const size_t MaxSections = 16;
+static size_t SectionCount = 0;
+static struct Section Sections[MaxSections];
+
+void *addSection(size_t Size, LLVMBool IsCode) {
+ if (SectionCount >= MaxSections) {
+ fprintf(stderr, "addSection(): Too many sections!\n");
+ abort();
+ }
+
+#if defined(_WIN32)
+ void *Ptr =
+ VirtualAlloc(NULL, Size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+ if (!Ptr) {
+ fprintf(stderr, "addSection(): Memory allocation failed!\n");
+ abort();
+ }
+#else
+ void *Ptr = mmap(NULL, Size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (Ptr == MAP_FAILED) {
+ fprintf(stderr, "addSection(): Memory allocation failed!\n");
+ abort();
+ }
+#endif
+
+ Sections[SectionCount].Ptr = Ptr;
+ Sections[SectionCount].Size = Size;
+ Sections[SectionCount].IsCode = IsCode;
+ SectionCount++;
+ return Ptr;
+}
+
+// Callbacks to create the context for the subsequent functions (not used in
+// this example)
+void *memCreateContext(void *CtxCtx) {
+ assert(CtxCtx == &CtxCtxPlaceholder && "Unexpected CtxCtx value");
+ return &CtxPlaceholder;
+}
+
+void memNotifyTerminating(void *CtxCtx) {
+ assert(CtxCtx == &CtxCtxPlaceholder && "Unexpected CtxCtx value");
+}
+
+uint8_t *memAllocate(void *Opaque, uintptr_t Size, unsigned Align, unsigned Id,
+ const char *Name) {
+ printf("Allocated code section \"%s\"\n", Name);
+ return addSection(Size, 1);
+}
+
+uint8_t *memAllocateData(void *Opaque, uintptr_t Size, unsigned Align,
+ unsigned Id, const char *Name, LLVMBool ReadOnly) {
+ printf("Allocated data section \"%s\"\n", Name);
+ return addSection(Size, 0);
+}
+
+LLVMBool memFinalize(void *Opaque, char **Err) {
+ printf("Marking code sections as executable ..\n");
+ for (size_t i = 0; i < SectionCount; ++i) {
+ if (Sections[i].IsCode) {
+ LLVMBool fail;
+#if defined(_WIN32)
+ DWORD unused;
+ fail = VirtualProtect(Sections[i].Ptr, Sections[i].Size,
+ PAGE_EXECUTE_READ, &unused) == 0;
+#else
+ fail = mprotect(Sections[i].Ptr, Sections[i].Size,
+ PROT_READ | PROT_EXEC) == -1;
+#endif
+ if (fail) {
+ fprintf(stderr, "Could not mark code section as executable!\n");
+ abort();
+ }
+ }
+ }
+ return 0;
+}
+
+void memDestroy(void *Opaque) {
+ assert(Opaque == &CtxPlaceholder && "Unexpected Ctx value");
+ printf("Releasing section memory ..\n");
+ for (size_t i = 0; i < SectionCount; ++i) {
+ LLVMBool fail;
+#if defined(_WIN32)
+ fail = VirtualFree(Sections[i].Ptr, 0, MEM_RELEASE) == 0;
+#else
+ fail = munmap(Sections[i].Ptr, Sections[i].Size) == -1;
+#endif
+ if (fail) {
+ fprintf(stderr, "Could not release memory for section!");
+ abort();
+ }
+ }
+}
+
+LLVMOrcObjectLayerRef objectLinkingLayerCreator(void *Opaque,
+ LLVMOrcExecutionSessionRef ES,
+ const char *Triple) {
+ return LLVMOrcCreateRTDyldObjectLinkingLayerWithMCJITMemoryManagerLikeCallbacks(
+ ES, &CtxCtxPlaceholder, memCreateContext, memNotifyTerminating,
+ memAllocate, memAllocateData, memFinalize, memDestroy);
+}
+
+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;
+
+ LLVMOrcLLJITBuilderRef Builder = LLVMOrcCreateLLJITBuilder();
+ LLVMOrcLLJITBuilderSetObjectLinkingLayerCreator(
+ Builder, objectLinkingLayerCreator, NULL);
+
+ if ((Err = LLVMOrcCreateLLJIT(&J, Builder))) {
+ MainResult = handleError(Err);
+ goto llvm_shutdown;
+ }
+ }
+
+ // Create our demo module.
+ LLVMOrcThreadSafeModuleRef TSM = createDemoModule();
+
+ // Add our demo module to the JIT.
+ {
+ LLVMOrcJITDylibRef MainJD = LLVMOrcLLJITGetMainJITDylib(J);
+ LLVMErrorRef Err;
+ if ((Err = LLVMOrcLLJITAddLLVMIRModule(J, MainJD, 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.
+ 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);
+
+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.
+ {
+ LLVMErrorRef Err;
+ if ((Err = LLVMOrcDisposeLLJIT(J))) {
+ int NewFailureResult = handleError(Err);
+ if (MainResult == 0)
+ MainResult = NewFailureResult;
+ }
+ }
+
+llvm_shutdown:
+ // Shut down LLVM.
+ LLVMShutdown();
+
+ return MainResult;
+}
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