[llvm] [LLVM][TableGen] Add additional target independent intrinsic checks (PR #109826)

[Rahul Joshi via llvm-commits]

https://github.com/jurahul created https://github.com/llvm/llvm-project/pull/109826

Validate that for target independent intrinsics the second dotted component of their name (after the `llvm.`) does not match any existing target names (for which atleast one intrinsic has been defined). Doing so is invalid as LLVM will search for that intrinsic in that target's intrinsic table and not find it, and conclude that its an unknown intrinsic.

>From e9a62f9bbd452bf8d514ed04a7322013af700224 Mon Sep 17 00:00:00 2001
From: Rahul Joshi <rjoshi at nvidia.com>
Date: Tue, 24 Sep 2024 09:28:31 -0700
Subject: [PATCH] [LLVM][TableGen] Add additional target independent intrinsic
 checks

Validate that for target independent intrinsics the second dotted
component of their name (after the `llvm.`) does not match any existing
target names (for which atleast one intrinsic has been defined). Doing
so is invalid as LLVM will search for that intrinsic in that target's
intrinsic table and not find it, and conclude that its an unknown
intrinsic.
---
 ...ic-target-prefix-for-target-independent.td |  9 ++++++++
 .../TableGen/Basic/CodeGenIntrinsics.cpp      | 23 +++++++++++++++++++
 llvm/utils/TableGen/Basic/CodeGenIntrinsics.h |  1 +
 3 files changed, 33 insertions(+)
 create mode 100644 llvm/test/TableGen/intrinsic-target-prefix-for-target-independent.td

diff --git a/llvm/test/TableGen/intrinsic-target-prefix-for-target-independent.td b/llvm/test/TableGen/intrinsic-target-prefix-for-target-independent.td
new file mode 100644
index 00000000000000..157b9490439fca
--- /dev/null
+++ b/llvm/test/TableGen/intrinsic-target-prefix-for-target-independent.td
@@ -0,0 +1,9 @@
+// RUN: not llvm-tblgen -gen-intrinsic-enums -I %p/../../include %s 2>&1 | FileCheck %s -DFILE=%s
+
+include "llvm/IR/Intrinsics.td"
+
+// Check that target independent intrinsics with a prefix that matches a target
+// name are flagged.
+// CHECK: [[FILE]]:[[@LINE+1]]:5: error: target independent intrinsic `llvm.aarch64.foo' has prefix `llvm.aarch64` that conflicts with target intrinsics for target `aarch64`
+def int_aarch64_foo : Intrinsic<[],[]>;
+
diff --git a/llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp b/llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp
index a30dc72a83154a..b727795cb74db5 100644
--- a/llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp
+++ b/llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp
@@ -75,6 +75,7 @@ CodeGenIntrinsicTable::CodeGenIntrinsicTable(const RecordKeeper &RC) {
   Targets.back().Count = Intrinsics.size() - Targets.back().Offset;
 
   CheckDuplicateIntrinsics();
+  CheckTargetIndependentIntrinsics();
 }
 
 // Check for duplicate intrinsic names.
@@ -101,6 +102,28 @@ void CodeGenIntrinsicTable::CheckDuplicateIntrinsics() const {
   PrintFatalNote(First.TheDef, "Previous definition here");
 }
 
+// For target independent intrinsics, check that their second dotted component
+// does not match any target name.
+void CodeGenIntrinsicTable::CheckTargetIndependentIntrinsics() const {
+  SmallDenseSet<StringRef> TargetNames;
+  for (const auto &Target : ArrayRef(Targets).drop_front())
+    TargetNames.insert(Target.Name);
+
+  // Set of target independent intrinsics.
+  const auto &Set = Targets[0];
+  for (const auto &Int : ArrayRef(&Intrinsics[Set.Offset], Set.Count)) {
+    StringRef Name = Int.Name;
+    StringRef Prefix = Name.drop_front(5).split('.').first;
+    if (!TargetNames.contains(Prefix))
+      continue;
+    PrintFatalError(Int.TheDef,
+                    "target independent intrinsic `" + Name +
+                        "' has prefix `llvm." + Prefix +
+                        "` that conflicts with target intrinsics for target `" +
+                        Prefix + "`");
+  }
+}
+
 CodeGenIntrinsic &CodeGenIntrinsicMap::operator[](const Record *Record) {
   if (!Record->isSubClassOf("Intrinsic"))
     PrintFatalError("Intrinsic defs should be subclass of 'Intrinsic' class");
diff --git a/llvm/utils/TableGen/Basic/CodeGenIntrinsics.h b/llvm/utils/TableGen/Basic/CodeGenIntrinsics.h
index 2df598da3f2507..1cdeaacd52dcdb 100644
--- a/llvm/utils/TableGen/Basic/CodeGenIntrinsics.h
+++ b/llvm/utils/TableGen/Basic/CodeGenIntrinsics.h
@@ -192,6 +192,7 @@ class CodeGenIntrinsicTable {
 
 private:
   void CheckDuplicateIntrinsics() const;
+  void CheckTargetIndependentIntrinsics() const;
 };
 
 // This class builds `CodeGenIntrinsic` on demand for a given Def.