[llvm] 46402eb - Revert "[TableGen] Make the NUL character invalid in .td files"

[Paul C. Anagnostopoulos via llvm-commits]

Author: Paul C. Anagnostopoulos
Date: 2021-05-11T10:43:13-04:00
New Revision: 46402eb103d06b1e695ecfd6f6c9571615042a9c

URL: https://github.com/llvm/llvm-project/commit/46402eb103d06b1e695ecfd6f6c9571615042a9c
DIFF: https://github.com/llvm/llvm-project/commit/46402eb103d06b1e695ecfd6f6c9571615042a9c.diff

LOG: Revert "[TableGen] Make the NUL character invalid in .td files"

At least one build uses a 'sed' that does not understand \x00.

This reverts commit cf9647011c4f05e1eb4423c6637d84e2f26b2042.

Added: 
    

Modified: 
    llvm/lib/TableGen/TGLexer.cpp

Removed: 
    llvm/test/TableGen/nul-char.td


################################################################################
diff  --git a/llvm/lib/TableGen/TGLexer.cpp b/llvm/lib/TableGen/TGLexer.cpp
index 2acac63ce8439..91229818077f8 100644
--- a/llvm/lib/TableGen/TGLexer.cpp
+++ b/llvm/lib/TableGen/TGLexer.cpp
@@ -108,19 +108,16 @@ int TGLexer::getNextChar() {
   switch (CurChar) {
   default:
     return (unsigned char)CurChar;
-
   case 0: {
-    // A NUL character in the stream is either the end of the current buffer or
-    // a spurious NUL in the file.  Disambiguate that here.
-    if (CurPtr - 1 == CurBuf.end()) {
-      --CurPtr; // Arrange for another call to return EOF again.
-      return EOF;
-    }
-    PrintError(getLoc(),
-               "NUL character is invalid in source; treated as space");
-    return ' ';
+    // A nul character in the stream is either the end of the current buffer or
+    // a random nul in the file.  Disambiguate that here.
+    if (CurPtr-1 != CurBuf.end())
+      return 0;  // Just whitespace.
+
+    // Otherwise, return end of file.
+    --CurPtr;  // Another call to lex will return EOF again.
+    return EOF;
   }
-
   case '\n':
   case '\r':
     // Handle the newline character by ignoring it and incrementing the line
@@ -200,6 +197,7 @@ tgtok::TokKind TGLexer::LexToken(bool FileOrLineStart) {
     PrintFatalError("getNextChar() must never return '\r'");
     return tgtok::Error;
 
+  case 0:
   case ' ':
   case '\t':
     // Ignore whitespace.
@@ -417,12 +415,22 @@ bool TGLexer::LexInclude() {
   return false;
 }
 
-/// SkipBCPLComment - Skip over the comment by finding the next CR or LF.
-/// Or we may end up at the end of the buffer.
 void TGLexer::SkipBCPLComment() {
   ++CurPtr;  // skip the second slash.
-  auto EOLPos = CurBuf.find_first_of("\r\n", CurPtr - CurBuf.data());
-  CurPtr = (EOLPos == StringRef::npos) ? CurBuf.end() : CurBuf.data() + EOLPos;
+  while (true) {
+    switch (*CurPtr) {
+    case '\n':
+    case '\r':
+      return;  // Newline is end of comment.
+    case 0:
+      // If this is the end of the buffer, end the comment.
+      if (CurPtr == CurBuf.end())
+        return;
+      break;
+    }
+    // Otherwise, skip the character.
+    ++CurPtr;
+  }
 }
 
 /// SkipCComment - This skips C-style /**/ comments.  The only 
diff erence from C

diff  --git a/llvm/test/TableGen/nul-char.td b/llvm/test/TableGen/nul-char.td
deleted file mode 100644
index fc56b6a87829a..0000000000000
--- a/llvm/test/TableGen/nul-char.td
+++ /dev/null
@@ -1,28 +0,0 @@
-// RUN: sed -e 's/@/\x00/g' %s > %t
-// RUN: not llvm-tblgen -DERROR1 %t 2>&1 | FileCheck --check-prefix=ERROR1 %s
-
-// This test file checks that NUL is treated as an invalid character.
-// Each at sign is replaced with a NUL before running the test.
-
-#ifdef ERROR1
-
-// ERROR1: error: NUL character is invalid in source; treated as space
-// ERROR1: error: NUL character is invalid in source; treated as space
-// ERROR1: error: NUL character is invalid in source; treated as space
-// ERROR1: error: NUL character is invalid in source; treated as space
-// ERROR1: error: expected ';' after declaration
-
-def Foo@ {
-  int @ ID = 42;
-}
-
-@
-
-// Comment with a NUL @ there. They are ignored in comments.
-
-def Bar {
-  int Biggie = 12345 at 789;
-}
-
-#endif
-