1 files changed, 93 insertions, 0 deletions
diff --git a/utils/TableGen/GlobalISel/CodeExpander.cpp b/utils/TableGen/GlobalISel/CodeExpander.cpp
new file mode 100644
index 000000000000..d59a9b8e3b65
--- /dev/null
+++ b/utils/TableGen/GlobalISel/CodeExpander.cpp
@@ -0,0 +1,93 @@
+//===- CodeExpander.cpp - Expand variables in a string --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file Expand the variables in a string.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeExpander.h"
+#include "CodeExpansions.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/TableGen/Error.h"
+
+using namespace llvm;
+
+void CodeExpander::emit(raw_ostream &OS) const {
+  StringRef Current = Code;
+
+  while (!Current.empty()) {
+    size_t Pos = Current.find_first_of("$\n\\");
+    if (Pos == StringRef::npos) {
+      OS << Current;
+      Current = "";
+      continue;
+    }
+
+    OS << Current.substr(0, Pos);
+    Current = Current.substr(Pos);
+
+    if (Current.startswith("\n")) {
+      OS << "\n" << Indent;
+      Current = Current.drop_front(1);
+      continue;
+    }
+
+    if (Current.startswith("\\$") || Current.startswith("\\\\")) {
+      OS << Current[1];
+      Current = Current.drop_front(2);
+      continue;
+    }
+
+    if (Current.startswith("\\")) {
+      Current = Current.drop_front(1);
+      continue;
+    }
+
+    if (Current.startswith("${")) {
+      StringRef StartVar = Current;
+      Current = Current.drop_front(2);
+      StringRef Var;
+      std::tie(Var, Current) = Current.split("}");
+
+      // Warn if we split because no terminator was found.
+      StringRef EndVar = StartVar.drop_front(2 /* ${ */ + Var.size());
+      if (EndVar.empty()) {
+        size_t LocOffset = StartVar.data() - Code.data();
+        PrintWarning(
+            Loc.size() > 0 && Loc[0].isValid()
+                ? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
+                : SMLoc(),
+            "Unterminated expansion");
+      }
+
+      auto ValueI = Expansions.find(Var);
+      if (ValueI == Expansions.end()) {
+        size_t LocOffset = StartVar.data() - Code.data();
+        PrintError(Loc.size() > 0 && Loc[0].isValid()
+                       ? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
+                       : SMLoc(),
+                   "Attempting to expand an undeclared variable " + Var);
+      }
+      if (ShowExpansions)
+        OS << "/*$" << Var << "{*/";
+      OS << Expansions.lookup(Var);
+      if (ShowExpansions)
+        OS << "/*}*/";
+      continue;
+    }
+
+    size_t LocOffset = Current.data() - Code.data();
+    PrintWarning(Loc.size() > 0 && Loc[0].isValid()
+                     ? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
+                     : SMLoc(),
+                 "Assuming missing escape character");
+    OS << "$";
+    Current = Current.drop_front(1);
+  }
+}