From 563a9cf7ba3055921b7de9f05dd9223e82d20aba Mon Sep 17 00:00:00 2001
From: Justin Holewinski <jholewinski@nvidia.com>
Date: Thu, 25 Jul 2013 12:32:00 +0000
Subject: [PATCH] Fix a bug in TableGen where the intrinsic function name
 recognizer could mis-identify names if one was a prefix substring of the
 other

For two intrinsics 'llvm.nvvm.texsurf.handle' and 'llvm.nvvm.texsurf.handle.internal',
TableGen was emitting matching code like:

  if (Name.startswith("llvm.nvvm.texsurf.handle")) ...
  if (Name.startswith("llvm.nvvm.texsurf.handle.internal")) ...

We can never match "llvm.nvvm.texsurf.handle.internal" here because it will
always be erroneously matched by the first condition.

The fix is to sort the intrinsic names and emit them in reverse order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187119 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/TableGen/intrinsic-order.td    | 35 +++++++++++++++++++++++++++++
 utils/TableGen/IntrinsicEmitter.cpp | 18 +++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 test/TableGen/intrinsic-order.td

diff --git a/test/TableGen/intrinsic-order.td b/test/TableGen/intrinsic-order.td
new file mode 100644
index 00000000000..5eadf60a6ef
--- /dev/null
+++ b/test/TableGen/intrinsic-order.td
@@ -0,0 +1,35 @@
+// RUN: llvm-tblgen -gen-intrinsic %s | FileCheck %s
+
+class IntrinsicProperty;
+
+class ValueType<int size, int value> {
+  string Namespace = "MVT";
+  int Size = size;
+  int Value = value;
+}
+
+class LLVMType<ValueType vt> {
+  ValueType VT = vt;
+}
+
+class Intrinsic<string name, list<LLVMType> param_types = []> {
+  string LLVMName = name;
+  bit isTarget = 0;
+  string TargetPrefix = "";
+  list<LLVMType> RetTypes = [];
+  list<LLVMType> ParamTypes = param_types;
+  list<IntrinsicProperty> Properties = [];
+}
+
+def iAny : ValueType<0, 254>;
+def llvm_anyint_ty : LLVMType<iAny>;
+
+
+// Make sure an intrinsic name that is a prefix of another is checked after the
+// other.
+
+// CHECK: if (NameR.startswith("oo.bar.")) return Intrinsic::foo_bar;
+// CHECK: if (NameR.startswith("oo.")) return Intrinsic::foo;
+
+def int_foo : Intrinsic<"llvm.foo", [llvm_anyint_ty]>;
+def int_foo_bar : Intrinsic<"llvm.foo.bar", [llvm_anyint_ty]>;
diff --git a/utils/TableGen/IntrinsicEmitter.cpp b/utils/TableGen/IntrinsicEmitter.cpp
index c83797c25df..c508795cc88 100644
--- a/utils/TableGen/IntrinsicEmitter.cpp
+++ b/utils/TableGen/IntrinsicEmitter.cpp
@@ -131,6 +131,20 @@ void IntrinsicEmitter::EmitEnumInfo(const std::vector<CodeGenIntrinsic> &Ints,
   OS << "#endif\n\n";
 }
 
+struct IntrinsicNameSorter {
+  IntrinsicNameSorter(const std::vector<CodeGenIntrinsic> &I)
+  : Ints(I) {}
+
+  // Sort in reverse order of intrinsic name so "abc.def" appears after
+  // "abd.def.ghi" in the overridden name matcher
+  bool operator()(unsigned i, unsigned j) {
+    return Ints[i].Name > Ints[j].Name;
+  }
+
+private:
+  const std::vector<CodeGenIntrinsic> &Ints;
+};
+
 void IntrinsicEmitter::
 EmitFnNameRecognizer(const std::vector<CodeGenIntrinsic> &Ints, 
                      raw_ostream &OS) {
@@ -144,12 +158,16 @@ EmitFnNameRecognizer(const std::vector<CodeGenIntrinsic> &Ints,
   OS << "  StringRef NameR(Name+6, Len-6);   // Skip over 'llvm.'\n";
   OS << "  switch (Name[5]) {                  // Dispatch on first letter.\n";
   OS << "  default: break;\n";
+  IntrinsicNameSorter Sorter(Ints);
   // Emit the intrinsic matching stuff by first letter.
   for (std::map<char, std::vector<unsigned> >::iterator I = IntMapping.begin(),
        E = IntMapping.end(); I != E; ++I) {
     OS << "  case '" << I->first << "':\n";
     std::vector<unsigned> &IntList = I->second;
 
+    // Sort intrinsics in reverse order of their names
+    std::sort(IntList.begin(), IntList.end(), Sorter);
+
     // Emit all the overloaded intrinsics first, build a table of the
     // non-overloaded ones.
     std::vector<StringMatcher::StringPair> MatchTable;