Exposing MCJIT through C API

Patch by Filip Pizlo



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180229 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm-c/ExecutionEngine.h

@@ -34,11 +34,17 @@ extern "C" {
  */
 
 void LLVMLinkInJIT(void);
+void LLVMLinkInMCJIT(void);
 void LLVMLinkInInterpreter(void);
 
 typedef struct LLVMOpaqueGenericValue *LLVMGenericValueRef;
 typedef struct LLVMOpaqueExecutionEngine *LLVMExecutionEngineRef;
 
+struct LLVMMCJITCompilerOptions {
+  unsigned OptLevel;
+  LLVMBool NoFramePointerElim;
+};
+
 /*===-- Operations on generic values --------------------------------------===*/
 
 LLVMGenericValueRef LLVMCreateGenericValueOfInt(LLVMTypeRef Ty,
@@ -75,6 +81,28 @@ LLVMBool LLVMCreateJITCompilerForModule(LLVMExecutionEngineRef *OutJIT,
                                         unsigned OptLevel,
                                         char **OutError);
 
+/**
+ * Create an MCJIT execution engine for a module, with the given options. It is
+ * the responsibility of the caller to ensure that all fields in Options up to
+ * the given SizeOfOptions are initialized. It is correct to pass a smaller value
+ * of SizeOfOptions that omits some fields, and it is also correct to set any
+ * field to zero. The canonical way of using this is:
+ *
+ * LLVMMCJITCompilerOptions options;
+ * memset(&options, 0, sizeof(options));
+ * ... fill in those options you care about
+ * LLVMCreateMCJITCompilerForModule(&jit, mod, &options, sizeof(options), &error);
+ *
+ * Note that this is also correct, though possibly suboptimal:
+ *
+ * LLVMCreateMCJITCompilerForModule(&jit, mod, 0, 0, &error);
+ */
+LLVMBool LLVMCreateMCJITCompilerForModule(LLVMExecutionEngineRef *OutJIT,
+                                          LLVMModuleRef M,
+                                          struct LLVMMCJITCompilerOptions *Options,
+                                          size_t SizeOfOptions,
+                                          char **OutError);
+
 /** Deprecated: Use LLVMCreateExecutionEngineForModule instead. */
 LLVMBool LLVMCreateExecutionEngine(LLVMExecutionEngineRef *OutEE,
                                    LLVMModuleProviderRef MP,

lib/ExecutionEngine/ExecutionEngineBindings.cpp

@@ -15,6 +15,7 @@
 #include "llvm-c/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/SectionMemoryManager.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <cstring>
 
@@ -152,6 +153,47 @@ LLVMBool LLVMCreateJITCompilerForModule(LLVMExecutionEngineRef *OutJIT,
   return 1;
 }
 
+LLVMBool LLVMCreateMCJITCompilerForModule(LLVMExecutionEngineRef *OutJIT,
+                                          LLVMModuleRef M,
+                                          LLVMMCJITCompilerOptions *PassedOptions,
+                                          size_t SizeOfPassedOptions,
+                                          char **OutError) {
+  LLVMMCJITCompilerOptions options;
+  // If the user passed a larger sized options struct, then they were compiled
+  // against a newer LLVM. Tell them that something is wrong.
+  if (SizeOfPassedOptions > sizeof(options)) {
+    *OutError = strdup(
+      "Refusing to use options struct that is larger than my own; assuming LLVM "
+      "library mismatch.");
+    return 1;
+  }
+  
+  // Defend against the user having an old version of the API by ensuring that
+  // any fields they didn't see are cleared. We must defend against fields being
+  // set to the bitwise equivalent of zero, and assume that this means "do the
+  // default" as if that option hadn't been available.
+  memset(&options, 0, sizeof(options));
+  memcpy(&options, PassedOptions, SizeOfPassedOptions);
+  
+  TargetOptions targetOptions;
+  targetOptions.NoFramePointerElim = options.NoFramePointerElim;
+
+  std::string Error;
+  EngineBuilder builder(unwrap(M));
+  builder.setEngineKind(EngineKind::JIT)
+         .setErrorStr(&Error)
+         .setUseMCJIT(true)
+         .setOptLevel((CodeGenOpt::Level)options.OptLevel)
+         .setJITMemoryManager(new SectionMemoryManager())
+         .setTargetOptions(targetOptions);
+  if (ExecutionEngine *JIT = builder.create()) {
+    *OutJIT = wrap(JIT);
+    return 0;
+  }
+  *OutError = strdup(Error.c_str());
+  return 1;
+}
+
 LLVMBool LLVMCreateExecutionEngine(LLVMExecutionEngineRef *OutEE,
                                    LLVMModuleProviderRef MP,
                                    char **OutError) {
@@ -196,6 +238,8 @@ void LLVMRunStaticDestructors(LLVMExecutionEngineRef EE) {
 int LLVMRunFunctionAsMain(LLVMExecutionEngineRef EE, LLVMValueRef F,
                           unsigned ArgC, const char * const *ArgV,
                           const char * const *EnvP) {
+  unwrap(EE)->finalizeObject();
+  
   std::vector<std::string> ArgVec;
   for (unsigned I = 0; I != ArgC; ++I)
     ArgVec.push_back(ArgV[I]);
@@ -206,6 +250,8 @@ int LLVMRunFunctionAsMain(LLVMExecutionEngineRef EE, LLVMValueRef F,
 LLVMGenericValueRef LLVMRunFunction(LLVMExecutionEngineRef EE, LLVMValueRef F,
                                     unsigned NumArgs,
                                     LLVMGenericValueRef *Args) {
+  unwrap(EE)->finalizeObject();
+  
   std::vector<GenericValue> ArgVec;
   ArgVec.reserve(NumArgs);
   for (unsigned I = 0; I != NumArgs; ++I)
@@ -268,5 +314,7 @@ void LLVMAddGlobalMapping(LLVMExecutionEngineRef EE, LLVMValueRef Global,
 }
 
 void *LLVMGetPointerToGlobal(LLVMExecutionEngineRef EE, LLVMValueRef Global) {
+  unwrap(EE)->finalizeObject();
+  
   return unwrap(EE)->getPointerToGlobal(unwrap<GlobalValue>(Global));
 }

unittests/ExecutionEngine/MCJIT/CMakeLists.txt

@@ -9,6 +9,7 @@ set(LLVM_LINK_COMPONENTS
 
 set(MCJITTestsSources
   MCJITTest.cpp
+  MCJITCAPITest.cpp
   MCJITMemoryManagerTest.cpp
   MCJITObjectCacheTest.cpp
   )

unittests/ExecutionEngine/MCJIT/MCJITCAPITest.cpp

@@ -0,0 +1,93 @@
+//===- MCJITTest.cpp - Unit tests for the MCJIT ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This test suite verifies basic MCJIT functionality when invoked form the C
+// API.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-c/Analysis.h"
+#include "llvm-c/Core.h"
+#include "llvm-c/ExecutionEngine.h"
+#include "llvm-c/Target.h"
+#include "llvm-c/Transforms/Scalar.h"
+#include "llvm/Support/Host.h"
+#include "MCJITTestAPICommon.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+class MCJITCAPITest : public testing::Test, public MCJITTestAPICommon {
+protected:
+  MCJITCAPITest() {
+    // The architectures below are known to be compatible with MCJIT as they
+    // are copied from test/ExecutionEngine/MCJIT/lit.local.cfg and should be
+    // kept in sync.
+    SupportedArchs.push_back(Triple::arm);
+    SupportedArchs.push_back(Triple::mips);
+    SupportedArchs.push_back(Triple::x86);
+    SupportedArchs.push_back(Triple::x86_64);
+
+    // The operating systems below are known to be sufficiently incompatible
+    // that they will fail the MCJIT C API tests.
+    UnsupportedOSs.push_back(Triple::Cygwin);
+  }
+};
+
+TEST_F(MCJITCAPITest, simple_function) {
+  SKIP_UNSUPPORTED_PLATFORM;
+  
+  char *error = 0;
+  
+  // Creates a function that returns 42, compiles it, and runs it.
+  
+  LLVMModuleRef module = LLVMModuleCreateWithName("simple_module");
+  
+  LLVMValueRef function = LLVMAddFunction(
+    module, "simple_function", LLVMFunctionType(LLVMInt32Type(), 0, 0, 0));
+  LLVMSetFunctionCallConv(function, LLVMCCallConv);
+  
+  LLVMBasicBlockRef entry = LLVMAppendBasicBlock(function, "entry");
+  LLVMBuilderRef builder = LLVMCreateBuilder();
+  LLVMPositionBuilderAtEnd(builder, entry);
+  LLVMBuildRet(builder, LLVMConstInt(LLVMInt32Type(), 42, 0));
+  
+  LLVMVerifyModule(module, LLVMAbortProcessAction, &error);
+  LLVMDisposeMessage(error);
+  
+  LLVMDisposeBuilder(builder);
+  
+  LLVMMCJITCompilerOptions options;
+  memset(&options, 0, sizeof(options));
+  options.OptLevel = 2;
+  options.NoFramePointerElim = false; // Just ensure that this field still exists.
+  
+  LLVMExecutionEngineRef engine;
+  ASSERT_EQ(
+    0, LLVMCreateMCJITCompilerForModule(&engine, module, &options, sizeof(options),
+                                        &error));
+  
+  LLVMPassManagerRef pass = LLVMCreatePassManager();
+  LLVMAddTargetData(LLVMGetExecutionEngineTargetData(engine), pass);
+  LLVMAddConstantPropagationPass(pass);
+  LLVMAddInstructionCombiningPass(pass);
+  LLVMRunPassManager(pass, module);
+  LLVMDisposePassManager(pass);
+  
+  union {
+    void *raw;
+    int (*usable)();
+  } functionPointer;
+  functionPointer.raw = LLVMGetPointerToGlobal(engine, function);
+  
+  EXPECT_EQ(42, functionPointer.usable());
+  
+  LLVMDisposeExecutionEngine(engine);
+}
+

unittests/ExecutionEngine/MCJIT/MCJITTestAPICommon.h

@@ -0,0 +1,77 @@
+//===- MCJITTestBase.h - Common base class for MCJIT Unit tests  ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class implements functionality shared by both MCJIT C API tests, and
+// the C++ API tests.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MCJIT_TEST_API_COMMON_H
+#define MCJIT_TEST_API_COMMON_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/TargetSelect.h"
+
+// Used to skip tests on unsupported architectures and operating systems.
+// To skip a test, add this macro at the top of a test-case in a suite that
+// inherits from MCJITTestBase. See MCJITTest.cpp for examples.
+#define SKIP_UNSUPPORTED_PLATFORM \
+  do \
+    if (!ArchSupportsMCJIT() || !OSSupportsMCJIT()) \
+      return; \
+  while(0)
+
+namespace llvm {
+
+class MCJITTestAPICommon {
+protected:
+  MCJITTestAPICommon()
+    : HostTriple(sys::getProcessTriple())
+  {
+    InitializeNativeTarget();
+    InitializeNativeTargetAsmPrinter();
+
+#ifdef LLVM_ON_WIN32
+    // On Windows, generate ELF objects by specifying "-elf" in triple
+    HostTriple += "-elf";
+#endif // LLVM_ON_WIN32
+    HostTriple = Triple::normalize(HostTriple);
+  }
+
+  /// Returns true if the host architecture is known to support MCJIT
+  bool ArchSupportsMCJIT() {
+    Triple Host(HostTriple);
+    if (std::find(SupportedArchs.begin(), SupportedArchs.end(), Host.getArch())
+        == SupportedArchs.end()) {
+      return false;
+    }
+    return true;
+  }
+
+  /// Returns true if the host OS is known to support MCJIT
+  bool OSSupportsMCJIT() {
+    Triple Host(HostTriple);
+    if (std::find(UnsupportedOSs.begin(), UnsupportedOSs.end(), Host.getOS())
+        == UnsupportedOSs.end()) {
+      return true;
+    }
+    return false;
+  }
+
+  std::string HostTriple;
+  SmallVector<Triple::ArchType, 4> SupportedArchs;
+  SmallVector<Triple::OSType, 4> UnsupportedOSs;
+};
+
+} // namespace llvm
+
+#endif // MCJIT_TEST_API_COMMON_H
+

unittests/ExecutionEngine/MCJIT/MCJITTestBase.h

@@ -17,8 +17,6 @@
 #ifndef MCJIT_TEST_BASE_H
 #define MCJIT_TEST_BASE_H
 
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Triple.h"
 #include "llvm/Config/config.h"
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
@@ -28,21 +26,11 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/TypeBuilder.h"
 #include "llvm/Support/CodeGen.h"
-#include "llvm/Support/Host.h"
-#include "llvm/Support/TargetSelect.h"
-
-// Used to skip tests on unsupported architectures and operating systems.
-// To skip a test, add this macro at the top of a test-case in a suite that
-// inherits from MCJITTestBase. See MCJITTest.cpp for examples.
-#define SKIP_UNSUPPORTED_PLATFORM \
-  do \
-    if (!ArchSupportsMCJIT() || !OSSupportsMCJIT()) \
-      return; \
-  while(0);
+#include "MCJITTestAPICommon.h"
 
 namespace llvm {
 
-class MCJITTestBase {
+class MCJITTestBase : public MCJITTestAPICommon {
 protected:
 
   MCJITTestBase()
@@ -52,17 +40,7 @@ protected:
     , MArch("")
     , Builder(Context)
     , MM(new SectionMemoryManager)
-    , HostTriple(sys::getProcessTriple())
   {
-    InitializeNativeTarget();
-    InitializeNativeTargetAsmPrinter();
-
-#ifdef LLVM_ON_WIN32
-    // On Windows, generate ELF objects by specifying "-elf" in triple
-    HostTriple += "-elf";
-#endif // LLVM_ON_WIN32
-    HostTriple = Triple::normalize(HostTriple);
-
     // The architectures below are known to be compatible with MCJIT as they
     // are copied from test/ExecutionEngine/MCJIT/lit.local.cfg and should be
     // kept in sync.
@@ -78,26 +56,6 @@ protected:
     UnsupportedOSs.push_back(Triple::Darwin);
   }
 
-  /// Returns true if the host architecture is known to support MCJIT
-  bool ArchSupportsMCJIT() {
-    Triple Host(HostTriple);
-    if (std::find(SupportedArchs.begin(), SupportedArchs.end(), Host.getArch())
-        == SupportedArchs.end()) {
-      return false;
-    }
-    return true;
-  }
-
-  /// Returns true if the host OS is known to support MCJIT
-  bool OSSupportsMCJIT() {
-    Triple Host(HostTriple);
-    if (std::find(UnsupportedOSs.begin(), UnsupportedOSs.end(), Host.getOS())
-        == UnsupportedOSs.end()) {
-      return true;
-    }
-    return false;
-  }
-
   Module *createEmptyModule(StringRef Name) {
     Module * M = new Module(Name, Context);
     M->setTargetTriple(Triple::normalize(HostTriple));
@@ -232,10 +190,6 @@ protected:
   IRBuilder<> Builder;
   JITMemoryManager *MM;
 
-  std::string HostTriple;
-  SmallVector<Triple::ArchType, 4> SupportedArchs;
-  SmallVector<Triple::OSType, 4> UnsupportedOSs;
-
   OwningPtr<Module> M;
 };