[Mlir-commits] [mlir] 7e54ae2 - [mlir][llvm] Do not inline variadic functions (#77241)

[llvmlistbot at llvm.org]

Author: Tobias Gysi
Date: 2024-01-08T08:30:10+01:00
New Revision: 7e54ae24d84bce4452ac4a28acb6568db52980fb

URL: https://github.com/llvm/llvm-project/commit/7e54ae24d84bce4452ac4a28acb6568db52980fb
DIFF: https://github.com/llvm/llvm-project/commit/7e54ae24d84bce4452ac4a28acb6568db52980fb.diff

LOG: [mlir][llvm] Do not inline variadic functions (#77241)

This revision updates the llvm dialect inliner to explicitly disallow
the inlining of variadic functions. Already previously the inlining
failed if the number of function arguments did not match the number of
call arguments. After the change, inlining checks the function is not
variadic and it does not contain a va_start intrinsic.

Added: 
    

Modified: 
    mlir/lib/Dialect/LLVMIR/IR/LLVMInlining.cpp
    mlir/test/Dialect/LLVMIR/inlining.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMInlining.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMInlining.cpp
index 65c1daee6711adc..4a6154ea6d3004e 100644
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMInlining.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMInlining.cpp
@@ -663,6 +663,10 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
                  << "Cannot inline: callable is not an LLVM::LLVMFuncOp\n");
       return false;
     }
+    if (funcOp.isVarArg()) {
+      LLVM_DEBUG(llvm::dbgs() << "Cannot inline: callable is variadic\n");
+      return false;
+    }
     // TODO: Generate aliasing metadata from noalias argument/result attributes.
     if (auto attrs = funcOp.getArgAttrs()) {
       for (DictionaryAttr attrDict : attrs->getAsRange<DictionaryAttr>()) {
@@ -704,7 +708,8 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
   }
 
   bool isLegalToInline(Operation *op, Region *, bool, IRMapping &) const final {
-    return true;
+    // The inliner cannot handle variadic function arguments.
+    return !isa<LLVM::VaStartOp>(op);
   }
 
   /// Handle the given inlined return by replacing it with a branch. This

diff  --git a/mlir/test/Dialect/LLVMIR/inlining.mlir b/mlir/test/Dialect/LLVMIR/inlining.mlir
index 63e7a46f1bdb060..3af8753bc318ab8 100644
--- a/mlir/test/Dialect/LLVMIR/inlining.mlir
+++ b/mlir/test/Dialect/LLVMIR/inlining.mlir
@@ -644,3 +644,28 @@ llvm.func @caller(%ptr : !llvm.ptr) -> i32 {
   llvm.store %c5, %ptr { access_groups = [#caller] } : i32, !llvm.ptr
   llvm.return %0 : i32
 }
+
+// -----
+
+llvm.func @vararg_func(...) {
+  llvm.return
+}
+
+llvm.func @vararg_intrinrics() {
+  %0 = llvm.mlir.constant(1 : i32) : i32
+  %list = llvm.alloca %0 x !llvm.struct<"struct.va_list_opaque", (ptr)> : (i32) -> !llvm.ptr
+  // The vararg intinriscs should normally be part of a variadic function.
+  // However, this test uses a non-variadic function to ensure the presence of
+  // the intrinsic alone suffices to prevent inlining.
+  llvm.intr.vastart %list : !llvm.ptr
+  llvm.return
+}
+
+// CHECK-LABEL: func @caller
+llvm.func @caller() {
+  // CHECK-NEXT: llvm.call @vararg_func()
+  llvm.call @vararg_func() vararg(!llvm.func<void (...)>) : () -> ()
+  // CHECK-NEXT: llvm.call @vararg_intrinrics()
+  llvm.call @vararg_intrinrics() : () -> ()
+  llvm.return
+}