[PATCH] D114003: LiteralSupport: Don't assert() on invalid input

[Daan De Meyer via Phabricator via cfe-commits]

DaanDeMeyer created this revision.
DaanDeMeyer added reviewers: eduucaldas, beccadax, sammccall, kadircet.
DaanDeMeyer added a project: clang.
Herald added a subscriber: usaxena95.
DaanDeMeyer requested review of this revision.
Herald added subscribers: cfe-commits, ilya-biryukov.

  When using clangd, it's possible to trigger assertions in
  NumericLiteralParser and CharLiteralParser when switching git branches.
  This commit removes the initial asserts on invalid input and replaces
  those asserts with the error handling mechanism from those respective
  classes instead. This allows clangd to gracefully recover without
  crashing.
  
  See https://github.com/clangd/clangd/issues/888 for more information
  on the clangd crashes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D114003

Files:
  clang/lib/Lex/LiteralSupport.cpp


Index: clang/lib/Lex/LiteralSupport.cpp
===================================================================
--- clang/lib/Lex/LiteralSupport.cpp
+++ clang/lib/Lex/LiteralSupport.cpp
@@ -693,12 +693,6 @@
     : SM(SM), LangOpts(LangOpts), Diags(Diags),
       ThisTokBegin(TokSpelling.begin()), ThisTokEnd(TokSpelling.end()) {
 
-  // This routine assumes that the range begin/end matches the regex for integer
-  // and FP constants (specifically, the 'pp-number' regex), and assumes that
-  // the byte at "*end" is both valid and not part of the regex.  Because of
-  // this, it doesn't have to check for 'overscan' in various places.
-  assert(!isPreprocessingNumberBody(*ThisTokEnd) && "didn't maximally munch?");
-
   s = DigitsBegin = ThisTokBegin;
   saw_exponent = false;
   saw_period = false;
@@ -718,6 +712,16 @@
   isAccum = false;
   hadError = false;
 
+  // This routine assumes that the range begin/end matches the regex for integer
+  // and FP constants (specifically, the 'pp-number' regex), and assumes that
+  // the byte at "*end" is both valid and not part of the regex.  Because of
+  // this, it doesn't have to check for 'overscan' in various places.
+  if (isPreprocessingNumberBody(*ThisTokEnd)) {
+      Diags.Report(TokLoc, diag::err_lexing_string);
+      hadError = true;
+      return;
+  }
+
   if (*s == '0') { // parse radix
     ParseNumberStartingWithZero(TokLoc);
     if (hadError)
@@ -1432,7 +1436,12 @@
     ++begin;
 
   // Skip over the entry quote.
-  assert(begin[0] == '\'' && "Invalid token lexed");
+  if (begin[0] != '\'') {
+    PP.Diag(Loc, diag::err_lexing_string);
+    HadError = true;
+    return;
+  }
+
   ++begin;
 
   // Remove an optional ud-suffix.


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