[llvm] [LLVM][IR] Add location tracking to LLVM IR parser (PR #155797)

[via llvm-commits]

Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>,
Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>,
Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>,Bertik23
 <39457484+Bertik23 at users.noreply.github.com>,
Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>,
Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>,
Albert =?utf-8?q?Havliček?= <ahavlicek at azul.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/155797 at github.com>


================
@@ -174,27 +165,75 @@ LLLexer::LLLexer(StringRef StartBuf, SourceMgr &SM, SMDiagnostic &Err,
   CurPtr = CurBuf.begin();
 }
 
+const char *LLLexer::getLabelTail(const char *Ptr) {
+  while (Ptr != CurBuf.end()) {
+    if (Ptr[0] == ':')
+      return Ptr + 1;
+    if (!isLabelChar(Ptr[0]))
+      return nullptr;
+    ++Ptr;
+  }
+  return nullptr;
+}
+
 int LLLexer::getNextChar() {
-  char CurChar = *CurPtr++;
-  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 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.
+  if (CurPtr == CurBuf.end())
     return EOF;
+  // Increment line number if this is the first character after a newline
+  if (CurPtr > CurBuf.begin() && *(CurPtr - 1) == '\n') {
----------------
Bertik23 wrote:

This comment made me look into the implementation of SourceMgr, turns out, that the documentation comment about getting line and column location being slow is wrong, the implementation was improved and the comment wasn't changed.

So I updated the code to use the SourceMgr to resolve locations from the pointer.

https://github.com/llvm/llvm-project/pull/155797