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Disallow inlining for selected function attributes #7

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75 changes: 25 additions & 50 deletions mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2850,15 +2850,37 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
auto funcOp = dyn_cast<LLVM::LLVMFuncOp>(callable);
if (!callOp || !funcOp)
return false;
return isLegalToInlineCallAttributes(callOp) &&
isLegalToInlineFuncAttributes(funcOp);
// TODO: Handle argument and result attributes;
if (funcOp.getArgAttrs() || funcOp.getResAttrs())
return false;
// TODO: Handle exceptions.
if (funcOp.getPersonality())
return false;
if (funcOp.getPassthrough()) {
// TODO: Used attributes should not be passthrough.
DenseSet<StringAttr> disallowed(
{StringAttr::get(funcOp->getContext(), "noduplicate"),
StringAttr::get(funcOp->getContext(), "noinline"),
StringAttr::get(funcOp->getContext(), "optnone"),
StringAttr::get(funcOp->getContext(), "presplitcoroutine"),
StringAttr::get(funcOp->getContext(), "returns_twice"),
StringAttr::get(funcOp->getContext(), "strictfp")});
if (llvm::any_of(*funcOp.getPassthrough(), [&](Attribute attr) {
auto stringAttr = dyn_cast<StringAttr>(attr);
if (!stringAttr)
return false;
return disallowed.contains(stringAttr);
}))
return false;
}
return true;
}

bool isLegalToInline(Region *, Region *, bool, IRMapping &) const final {
return true;
}

/// Conservative allowlist-based inlining of operations supported so far.
/// Conservative allowlist of operations supported so far.
bool isLegalToInline(Operation *op, Region *, bool, IRMapping &) const final {
if (isPure(op))
return true;
Expand Down Expand Up @@ -2919,53 +2941,6 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
// which newly inlined block was previously the entry block of the callee.
moveConstantAllocasToEntryBlock(inlinedBlocks);
}

private:
/// Returns true if all attributes of `callOp` are handled during inlining.
[[nodiscard]] static bool isLegalToInlineCallAttributes(LLVM::CallOp callOp) {
return all_of(callOp.getAttributeNames(), [&](StringRef attrName) {
return llvm::StringSwitch<bool>(attrName)
// TODO: Propagate and update branch weights.
.Case("branch_weights", !callOp.getBranchWeights())
.Case("callee", true)
.Case("fastmathFlags", true)
.Default(false);
});
}

/// Returns true if all attributes of `funcOp` are handled during inlining.
[[nodiscard]] static bool
isLegalToInlineFuncAttributes(LLVM::LLVMFuncOp funcOp) {
return all_of(funcOp.getAttributeNames(), [&](StringRef attrName) {
return llvm::StringSwitch<bool>(attrName)
.Case("CConv", true)
.Case("arg_attrs", ([&]() {
if (!funcOp.getArgAttrs())
return true;
return llvm::all_of(funcOp.getArgAttrs().value(),
[&](Attribute) {
// TODO: Handle argument attributes.
return false;
});
})())
.Case("dso_local", true)
.Case("function_entry_count", true)
.Case("function_type", true)
// TODO: Once the garbage collector attribute is supported on
// LLVM::CallOp, make sure that the garbage collector matches.
.Case("garbageCollector", !funcOp.getGarbageCollector())
.Case("linkage", true)
.Case("memory", true)
.Case("passthrough", !funcOp.getPassthrough())
// Exception handling is not yet supported, so bail out if the
// personality is set.
.Case("personality", !funcOp.getPersonality())
// TODO: Handle result attributes.
.Case("res_attrs", !funcOp.getResAttrs())
.Case("sym_name", true)
.Default(false);
});
}
};
} // end anonymous namespace

Expand Down
60 changes: 28 additions & 32 deletions mlir/test/Dialect/LLVMIR/inlining.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ llvm.func internal fastcc @callee() -> (i32) attributes { function_entry_count =
// CHECK-NEXT: llvm.return %[[CST]]
llvm.func @caller() -> (i32) {
// Include all call attributes that don't prevent inlining.
%0 = llvm.call @callee() { fastmathFlags = #llvm.fastmath<nnan, ninf> } : () -> (i32)
%0 = llvm.call @callee() { fastmathFlags = #llvm.fastmath<nnan, ninf>, branch_weights = dense<42> : vector<1xi32> } : () -> (i32)
llvm.return %0 : i32
}

Expand Down Expand Up @@ -147,32 +147,42 @@ llvm.func @caller() -> (i32) {

// -----

llvm.func @callee() -> (i32) attributes { passthrough = ["foo"] } {
%0 = llvm.mlir.constant(42 : i32) : i32
llvm.return %0 : i32
llvm.func @callee() attributes { passthrough = ["foo", "bar"] } {
llvm.return
}

// CHECK-LABEL: llvm.func @caller
// CHECK-NEXT: llvm.call @callee
// CHECK-NEXT: return
llvm.func @caller() -> (i32) {
%0 = llvm.call @callee() : () -> (i32)
llvm.return %0 : i32
// CHECK-NEXT: llvm.return
llvm.func @caller() {
llvm.call @callee() : () -> ()
llvm.return
}

// -----

llvm.func @callee() -> (i32) attributes { garbageCollector = "foo" } {
%0 = llvm.mlir.constant(42 : i32) : i32
llvm.return %0 : i32
}
llvm.func @callee_noinline() attributes { passthrough = ["noinline"] }
llvm.func @callee_optnone() attributes { passthrough = ["optnone"] }
llvm.func @callee_noduplicate() attributes { passthrough = ["noduplicate"] }
llvm.func @callee_presplitcoroutine() attributes { passthrough = ["presplitcoroutine"] }
llvm.func @callee_returns_twice() attributes { passthrough = ["returns_twice"] }
llvm.func @callee_strictfp() attributes { passthrough = ["strictfp"] }

// CHECK-LABEL: llvm.func @caller
// CHECK-NEXT: llvm.call @callee
// CHECK-NEXT: return
llvm.func @caller() -> (i32) {
%0 = llvm.call @callee() : () -> (i32)
llvm.return %0 : i32
// CHECK-NEXT: llvm.call @callee_noinline
// CHECK-NEXT: llvm.call @callee_optnone
// CHECK-NEXT: llvm.call @callee_noduplicate
// CHECK-NEXT: llvm.call @callee_presplitcoroutine
// CHECK-NEXT: llvm.call @callee_returns_twice
// CHECK-NEXT: llvm.call @callee_strictfp
// CHECK-NEXT: llvm.return
llvm.func @caller() {
llvm.call @callee_noinline() : () -> ()
llvm.call @callee_optnone() : () -> ()
llvm.call @callee_noduplicate() : () -> ()
llvm.call @callee_presplitcoroutine() : () -> ()
llvm.call @callee_returns_twice() : () -> ()
llvm.call @callee_strictfp() : () -> ()
llvm.return
}

// -----
Expand All @@ -191,20 +201,6 @@ llvm.func @caller(%ptr : !llvm.ptr) -> (!llvm.ptr) {

// -----

llvm.func @callee() {
llvm.return
}

// CHECK-LABEL: llvm.func @caller
// CHECK-NEXT: llvm.call @callee
// CHECK-NEXT: llvm.return
llvm.func @caller() {
llvm.call @callee() { branch_weights = dense<42> : vector<1xi32> } : () -> ()
llvm.return
}

// -----

llvm.func @static_alloca() -> f32 {
%0 = llvm.mlir.constant(4 : i32) : i32
%1 = llvm.alloca %0 x f32 : (i32) -> !llvm.ptr
Expand Down