[mlir][llvmir] expose Type(To/From)LLVMIRTranslator C API

[makslevental]

I'd like to enable the ability to convert between LLVM Types and MLIR Types using libMLIR-C only.

In addition I'd like to enable call_intrinsic return type inference, i.e., I'd like to retrieve intrinsic signatures without having to require/provide a return type. Thus, this PR adds TypeToLLVMIRTranslator::uncheckedGetIntrinsicSignature (and auxiliary code) which only requires an intrinsic ID and the parameter types (return type inference is handled by llvm::Intrinsic::getType).

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-llvm

Author: Maksim Levental (makslevental)

Changes

I'd like to expose the ability to convert between LLVM Types and MLIR Types using libMLIR-C only.

---

Full diff: https://github.com/llvm/llvm-project/pull/124864.diff

3 Files Affected:

• (modified) mlir/include/mlir-c/Target/LLVMIR.h (+15)
• (modified) mlir/lib/CAPI/Target/LLVMIR.cpp (+19-3)
• (modified) mlir/test/CAPI/translation.c (+17)

diff --git a/mlir/include/mlir-c/Target/LLVMIR.h b/mlir/include/mlir-c/Target/LLVMIR.h
index effa74b905ce66..90204626013952 100644
--- a/mlir/include/mlir-c/Target/LLVMIR.h
+++ b/mlir/include/mlir-c/Target/LLVMIR.h
@@ -32,6 +32,21 @@ extern "C" {
 MLIR_CAPI_EXPORTED LLVMModuleRef
 mlirTranslateModuleToLLVMIR(MlirOperation module, LLVMContextRef context);
 
+struct MlirTypeFromLLVMIRTranslator {
+  void *ptr;
+};
+
+typedef struct MlirTypeFromLLVMIRTranslator MlirTypeFromLLVMIRTranslator;
+
+MLIR_CAPI_EXPORTED MlirTypeFromLLVMIRTranslator
+mlirTypeFromLLVMIRTranslatorCreate(MlirContext ctx);
+
+MLIR_CAPI_EXPORTED MlirTypeFromLLVMIRTranslator
+mlirTypeFromLLVMIRTranslatorCreate(MlirContext ctx);
+
+MLIR_CAPI_EXPORTED MlirType mlirTypeFromLLVMIRTranslatorTranslateType(
+    MlirTypeFromLLVMIRTranslator translator, LLVMTypeRef llvmType);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/mlir/lib/CAPI/Target/LLVMIR.cpp b/mlir/lib/CAPI/Target/LLVMIR.cpp
index dc798372be7467..7d81b490ed0c7b 100644
--- a/mlir/lib/CAPI/Target/LLVMIR.cpp
+++ b/mlir/lib/CAPI/Target/LLVMIR.cpp
@@ -8,16 +8,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "mlir-c/Target/LLVMIR.h"
-#include "llvm-c/Support.h"
 
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
-#include <memory>
+#include "llvm/IR/Type.h"
 
 #include "mlir/CAPI/IR.h"
-#include "mlir/CAPI/Support.h"
 #include "mlir/CAPI/Wrap.h"
 #include "mlir/Target/LLVMIR/ModuleTranslation.h"
+#include "mlir/Target/LLVMIR/TypeFromLLVM.h"
 
 using namespace mlir;
 
@@ -34,3 +33,20 @@ LLVMModuleRef mlirTranslateModuleToLLVMIR(MlirOperation module,
 
   return moduleRef;
 }
+
+DEFINE_C_API_PTR_METHODS(MlirTypeFromLLVMIRTranslator,
+                         mlir::LLVM::TypeFromLLVMIRTranslator);
+
+MlirTypeFromLLVMIRTranslator
+mlirTypeFromLLVMIRTranslatorCreate(MlirContext ctx) {
+  MLIRContext *context = unwrap(ctx);
+  auto *translator = new LLVM::TypeFromLLVMIRTranslator(*context);
+  return wrap(translator);
+}
+
+MlirType mlirTypeFromLLVMIRTranslatorTranslateType(
+    MlirTypeFromLLVMIRTranslator translator, LLVMTypeRef llvmType) {
+  LLVM::TypeFromLLVMIRTranslator *translator_ = unwrap(translator);
+  mlir::Type type = translator_->translateType(llvm::unwrap(llvmType));
+  return wrap(type);
+}
\ No newline at end of file
diff --git a/mlir/test/CAPI/translation.c b/mlir/test/CAPI/translation.c
index c9233d95fd5120..ddbf217c1d9862 100644
--- a/mlir/test/CAPI/translation.c
+++ b/mlir/test/CAPI/translation.c
@@ -58,11 +58,28 @@ static void testToLLVMIR(MlirContext ctx) {
   LLVMContextDispose(llvmCtx);
 }
 
+// CHECK-LABEL: testTypeFromLLVMIRTranslator
+static void testTypeFromLLVMIRTranslator(MlirContext ctx) {
+  fprintf(stderr, "testTypeFromLLVMIRTranslator\n");
+  LLVMContextRef llvmCtx = LLVMContextCreate();
+
+  LLVMTypeRef llvmTy = LLVMInt32TypeInContext(llvmCtx);
+  MlirTypeFromLLVMIRTranslator translator =
+      mlirTypeFromLLVMIRTranslatorCreate(ctx);
+  MlirType mlirTy =
+      mlirTypeFromLLVMIRTranslatorTranslateType(translator, llvmTy);
+  // CHECK: i32
+  mlirTypeDump(mlirTy);
+
+  LLVMContextDispose(llvmCtx);
+}
+
 int main(void) {
   MlirContext ctx = mlirContextCreate();
   mlirDialectHandleRegisterDialect(mlirGetDialectHandle__llvm__(), ctx);
   mlirContextGetOrLoadDialect(ctx, mlirStringRefCreateFromCString("llvm"));
   testToLLVMIR(ctx);
+  testTypeFromLLVMIRTranslator(ctx);
   mlirContextDestroy(ctx);
   return 0;
 }

[makslevental]

As discussed offline, I've removed uncheckedGetIntrinsicSignature and will replace it (elsewhere) with direct uses of LLVM C APIs.

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[zero9178]

LGTM!

[kazutakahirata]

I've merged 0e43b95 to fix warnings from this PR.

[makslevental]

I've merged 0e43b95 to fix warnings from this PR.

Thank you for that (and sorry for both missing them and stepping) but does this resolve the other buildbot failures? I got this in an email

/usr/bin/ld: tools/mlir/lib/CAPI/Target/CMakeFiles/obj.MLIRCAPITarget.dir/LLVMIR.cpp.o: in function `mlirTypeFromLLVMIRTranslatorCreate':
LLVMIR.cpp:(.text.mlirTypeFromLLVMIRTranslatorCreate+0x20): undefined reference to `mlir::LLVM::TypeFromLLVMIRTranslator::TypeFromLLVMIRTranslator(mlir::MLIRContext&)'
/usr/bin/ld: tools/mlir/lib/CAPI/Target/CMakeFiles/obj.MLIRCAPITarget.dir/LLVMIR.cpp.o: in function `mlirTypeFromLLVMIRTranslatorDestroy':
LLVMIR.cpp:(.text.mlirTypeFromLLVMIRTranslatorDestroy+0x14): undefined reference to `mlir::LLVM::TypeFromLLVMIRTranslator::~TypeFromLLVMIRTranslator()'
/usr/bin/ld: tools/mlir/lib/CAPI/Target/CMakeFiles/obj.MLIRCAPITarget.dir/LLVMIR.cpp.o: in function `mlirTypeFromLLVMIRTranslatorTranslateType':
LLVMIR.cpp:(.text.mlirTypeFromLLVMIRTranslatorTranslateType+0x0): undefined reference to `mlir::LLVM::TypeFromLLVMIRTranslator::translateType(llvm::Type*)'

[makslevental]

I reverted both 345512c