This exposes more MCJIT options via the C API:

CodeModel: It's now possible to create an MCJIT instance with any CodeModel you like.  Previously it was only possible to 
create an MCJIT that used CodeModel::JITDefault.

EnableFastISel: It's now possible to turn on the fast instruction selector.

The CodeModel option required some trickery.  The problem is that previously, we were ensuring future binary compatibility in 
the MCJITCompilerOptions by mandating that the user bzero's the options struct and passes the sizeof() that he saw; the 
bindings then bzero the remaining bits.  This works great but assumes that the bitwise zero equivalent of any field is a 
sensible default value.

But this is not the case for LLVMCodeModel, or its internal equivalent, llvm::CodeModel::Model.  In both of those, the default 
for a JIT is CodeModel::JITDefault (or LLVMCodeModelJITDefault), which is not bitwise zero.

Hence this change introduces LLVMInitializeMCJITCompilerOptions(), which will initialize the user's options struct with
defaults. The user will use this in the same way that they would have previously used memset() or bzero(). MCJITCAPITest.cpp
illustrates the change, as does the comment in ExecutionEngine.h.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180893 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 57 insertions, 11 deletions

diff --git a/include/llvm-c/ExecutionEngine.h b/include/llvm-c/ExecutionEngine.h
index 8b654d5..8fae77d 100644
--- a/include/llvm-c/ExecutionEngine.h
+++ b/include/llvm-c/ExecutionEngine.h
@@ -21,6 +21,7 @@
 
 #include "llvm-c/Core.h"
 #include "llvm-c/Target.h"
+#include "llvm-c/TargetMachine.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -42,7 +43,9 @@ typedef struct LLVMOpaqueExecutionEngine *LLVMExecutionEngineRef;
 
 struct LLVMMCJITCompilerOptions {
   unsigned OptLevel;
+  LLVMCodeModel CodeModel;
   LLVMBool NoFramePointerElim;
+  LLVMBool EnableFastISel;
 };
 
 /*===-- Operations on generic values --------------------------------------===*/
@@ -81,27 +84,30 @@ LLVMBool LLVMCreateJITCompilerForModule(LLVMExecutionEngineRef *OutJIT,
                                         unsigned OptLevel,
                                         char **OutError);
 
+void LLVMInitializeMCJITCompilerOptions(
+  struct LLVMMCJITCompilerOptions *Options, size_t SizeOfOptions);
+
 /**
  * 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:
+ * the given SizeOfOptions are initialized. It is correct to pass a smaller
+ * value of SizeOfOptions that omits some fields. The canonical way of using
+ * this is:
  *
  * LLVMMCJITCompilerOptions options;
- * memset(&options, 0, sizeof(options));
+ * LLVMInitializeMCJITCompilerOptions(&options, sizeof(options));
  * ... fill in those options you care about
- * LLVMCreateMCJITCompilerForModule(&jit, mod, &options, sizeof(options), &error);
+ * 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);
+LLVMBool LLVMCreateMCJITCompilerForModule(
+  LLVMExecutionEngineRef *OutJIT, LLVMModuleRef M,
+  struct LLVMMCJITCompilerOptions *Options, size_t SizeOfOptions,
+  char **OutError);
 
 /** Deprecated: Use LLVMCreateExecutionEngineForModule instead. */
 LLVMBool LLVMCreateExecutionEngine(LLVMExecutionEngineRef *OutEE,
@@ -151,7 +157,8 @@ LLVMBool LLVMRemoveModuleProvider(LLVMExecutionEngineRef EE,
 LLVMBool LLVMFindFunction(LLVMExecutionEngineRef EE, const char *Name,
                           LLVMValueRef *OutFn);
 
-void *LLVMRecompileAndRelinkFunction(LLVMExecutionEngineRef EE, LLVMValueRef Fn);
+void *LLVMRecompileAndRelinkFunction(LLVMExecutionEngineRef EE,
+                                     LLVMValueRef Fn);
 
 LLVMTargetDataRef LLVMGetExecutionEngineTargetData(LLVMExecutionEngineRef EE);
 
diff --git a/include/llvm/Support/CodeGen.h b/include/llvm/Support/CodeGen.h
index 1b66c94..240eba6 100644
--- a/include/llvm/Support/CodeGen.h
+++ b/include/llvm/Support/CodeGen.h
@@ -15,6 +15,9 @@
 #ifndef LLVM_SUPPORT_CODEGEN_H
 #define LLVM_SUPPORT_CODEGEN_H
 
+#include "llvm-c/TargetMachine.h"
+#include "llvm/Support/ErrorHandling.h"
+
 namespace llvm {
 
   // Relocation model types.
@@ -47,6 +50,42 @@ namespace llvm {
     };
   }
 
+  // Create wrappers for C Binding types (see CBindingWrapping.h).
+  inline CodeModel::Model unwrap(LLVMCodeModel Model) {
+    switch (Model) {
+      case LLVMCodeModelDefault:
+        return CodeModel::Default;
+      case LLVMCodeModelJITDefault:
+        return CodeModel::JITDefault;
+      case LLVMCodeModelSmall:
+        return CodeModel::Small;
+      case LLVMCodeModelKernel:
+        return CodeModel::Kernel;
+      case LLVMCodeModelMedium:
+        return CodeModel::Medium;
+      case LLVMCodeModelLarge:
+        return CodeModel::Large;
+    }
+    return CodeModel::Default;
+  }
+
+  inline LLVMCodeModel wrap(CodeModel::Model Model) {
+    switch (Model) {
+      case CodeModel::Default:
+        return LLVMCodeModelDefault;
+      case CodeModel::JITDefault:
+        return LLVMCodeModelJITDefault;
+      case CodeModel::Small:
+        return LLVMCodeModelSmall;
+      case CodeModel::Kernel:
+        return LLVMCodeModelKernel;
+      case CodeModel::Medium:
+        return LLVMCodeModelMedium;
+      case CodeModel::Large:
+        return LLVMCodeModelLarge;
+    }
+    llvm_unreachable("Bad CodeModel!");
+  }
 }  // end llvm namespace
 
 #endif