[MLIR][mlir-link] Set alignment in LLVM mixin (#58)

Author: Jezurko

clang/lib/CIR/Dialect/IR/CIRLinkerInterface.cpp

@@ -164,6 +164,13 @@ class CIRSymbolLinkerInterface
     llvm_unreachable("unexpected operation");
   }
 
+  static void setAlignment(Operation *op, std::optional<uint64_t> align) {
+    if (auto gv = dyn_cast<cir::GlobalOp>(op))
+      return gv.setAlignment(align);
+    // FIXME: CIR does not (yet?) have alignment for functions
+    llvm_unreachable("unexpected operation");
+  }
+
   static bool isConstant(Operation *op) {
     if (auto gv = dyn_cast<cir::GlobalOp>(op))
       return gv.getConstant();

mlir/include/mlir/Dialect/LLVMIR/LLVMLinkerInterface.h

@@ -22,6 +22,7 @@ class LLVMSymbolLinkerInterface
   static UnnamedAddr getUnnamedAddr(Operation *op);
   static void setUnnamedAddr(Operation *op, UnnamedAddr val);
   static std::optional<uint64_t> getAlignment(Operation *op);
+  static void setAlignment(Operation *op, std::optional<uint64_t>);
   static bool isConstant(Operation *op);
   static llvm::StringRef getSection(Operation *op);
   static uint32_t getAddressSpace(Operation *op);

mlir/include/mlir/Linker/LLVMLinkerMixin.h

@@ -279,6 +279,14 @@ class LLVMLinkerMixin {
     const bool srcIsDeclaration = isDeclarationForLinker(pair.src);
     const bool dstIsDeclaration = isDeclarationForLinker(pair.dst);
 
+    std::optional<uint64_t> srcAlignment = derived.getAlignment(pair.src);
+    std::optional<uint64_t> dstAlignment = derived.getAlignment(pair.dst);
+    std::optional<uint64_t> alignment = std::nullopt;
+    if (srcAlignment || dstAlignment)
+      alignment = std::max(srcAlignment.value_or(1), dstAlignment.value_or(1));
+    derived.setAlignment(pair.src, alignment);
+    derived.setAlignment(pair.dst, alignment);
+
     if (isAppendingLinkage(dstLinkage)) {
       return ConflictResolution::LinkFromSrc;
     }

mlir/lib/Dialect/LLVMIR/IR/LLVMLinkerInterface.cpp

@@ -170,6 +170,17 @@ LLVM::LLVMSymbolLinkerInterface::getAlignment(Operation *op) {
   llvm_unreachable("unexpected operation");
 }
 
+void LLVM::LLVMSymbolLinkerInterface::setAlignment(
+    Operation *op, std::optional<uint64_t> align) {
+  if (auto gv = dyn_cast<LLVM::GlobalOp>(op))
+    return gv.setAlignment(align);
+  if (auto fn = dyn_cast<LLVM::LLVMFuncOp>(op))
+    return fn.setAlignment(align);
+  if (isa<LLVM::GlobalCtorsOp, LLVM::GlobalDtorsOp, LLVM::AliasOp>(op))
+    return;
+  llvm_unreachable("unexpected operation");
+}
+
 bool LLVM::LLVMSymbolLinkerInterface::isConstant(Operation *op) {
   if (auto gv = dyn_cast<LLVM::GlobalOp>(op))
     return gv.getConstant();

mlir/test/mlir-link/adapted/linkage2.mlir

@@ -1,8 +1,5 @@
 // RUN: mlir-link %s %p/Inputs/linkage2.mlir -o - | FileCheck %s
-// RUN: mlir-link %p/Inputs/linkage2.ll %s -o - | FileCheck %s
-
-// broken alignment resolution
-// XFAIL: *
+// RUN: mlir-link %p/Inputs/linkage2.mlir %s -o - | FileCheck %s
 
 module {
   llvm.mlir.global common @test1_a(0 : i8) {addr_space = 0 : i32} : i8
@@ -12,5 +9,5 @@ module {
   llvm.mlir.global common @test3_a(0 : i8) {addr_space = 0 : i32} : i8
 // CHECK-DAG: llvm.mlir.global common @test3_a(0 : i16)
   llvm.mlir.global common @test4_a(0 : i8) {addr_space = 0 : i32, alignment = 8 : i64} : i8
-// CHECK-DAG: llvm.mlir.global common @test4_a(0 : i16) {addr_space = {[0-9]+} : i32, alignment = 8 : i64}
+// CHECK-DAG: llvm.mlir.global common @test4_a(0 : i16) {addr_space = {{[0-9]+}} : i32, alignment = 8 : i64}
 }