Escape and unescape strings in the parser and printer so they can roundtrip,

print floating point in a structured form that we know can round trip,
enumerate attributes in the visitor so we print affine mapping attributes
symbolically (the majority of the testcase updates).

We still have an issue where the hexadecimal floating point syntax is reparsed
as an integer, but that can evolve in subsequent patches.

PiperOrigin-RevId: 208828876

1 files changed, 40 insertions, 3 deletions

diff --git a/mlir/lib/Parser/Token.cpp b/mlir/lib/Parser/Token.cpp
index 2bce68153c2..1b14ae0b88f 100644
--- a/mlir/lib/Parser/Token.cpp
+++ b/mlir/lib/Parser/Token.cpp
@@ -20,6 +20,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Token.h"
+#include "llvm/ADT/StringExtras.h"
 using namespace mlir;
 using llvm::SMLoc;
 using llvm::SMRange;
@@ -79,11 +80,47 @@ Optional<unsigned> Token::getIntTypeBitwidth() const {
 }
 
 /// Given a 'string' token, return its value, including removing the quote
-/// characters and unescaping the contents of the string.
+/// characters and unescaping the contents of the string.  The lexer has already
+/// verified that this token is valid.
 std::string Token::getStringValue() const {
+  assert(getKind() == string);
   // Start by dropping the quotes.
-  // TODO: Un-escape the string here instead of passing through the raw content.
-  return getSpelling().drop_front().drop_back().str();
+  StringRef bytes = getSpelling().drop_front().drop_back();
+
+  std::string result;
+  result.reserve(bytes.size());
+  for (unsigned i = 0, e = bytes.size(); i != e;) {
+    auto c = bytes[i++];
+    if (c != '\\') {
+      result.push_back(c);
+      continue;
+    }
+
+    assert(i + 1 < e && "invalid string should be caught by lexer");
+    auto c1 = bytes[i++];
+    switch (c1) {
+    case '"':
+    case '\\':
+      result.push_back(c1);
+      continue;
+    case 'n':
+      result.push_back('\n');
+      continue;
+    case 't':
+      result.push_back('\t');
+      continue;
+    default:
+      break;
+    }
+
+    assert(i + 1 < e && "invalid string should be caught by lexer");
+    auto c2 = bytes[i++];
+
+    assert(llvm::isHexDigit(c1) && llvm::isHexDigit(c2) && "invalid escape");
+    result.push_back((llvm::hexDigitValue(c1) << 4) | llvm::hexDigitValue(c2));
+  }
+
+  return result;
 }
 
 /// Given a hash_identifier token like #123, try to parse the number out of