From e4c6153cf199de5acdc62ca9ea54ccb7d0c203ff Mon Sep 17 00:00:00 2001
From: Nirav Dave <niravd@google.com>
Date: Sat, 1 Oct 2016 10:57:55 +0000
Subject: [PATCH] Revert "[MC] Prevent out of order HashDirective lexing in
 AsmLexer."

This reverts commit r282992 which appears to be causing an LTO test failure.

llvm-svn: 283034
---
 llvm/include/llvm/MC/MCParser/AsmLexer.h |  2 +-
 llvm/lib/MC/MCParser/AsmLexer.cpp        | 43 ++++++++++++++----------
 llvm/test/MC/AsmParser/pr28921.s         |  8 -----
 3 files changed, 27 insertions(+), 26 deletions(-)
 delete mode 100644 llvm/test/MC/AsmParser/pr28921.s

diff --git a/llvm/include/llvm/MC/MCParser/AsmLexer.h b/llvm/include/llvm/MC/MCParser/AsmLexer.h
index 029598c013d3..06937e25f59e 100644
--- a/llvm/include/llvm/MC/MCParser/AsmLexer.h
+++ b/llvm/include/llvm/MC/MCParser/AsmLexer.h
@@ -32,7 +32,7 @@ class AsmLexer : public MCAsmLexer {
   bool IsAtStartOfLine;
   bool IsAtStartOfStatement;
   bool IsParsingMSInlineAsm;
-  bool IsPeeking;
+
   void operator=(const AsmLexer&) = delete;
   AsmLexer(const AsmLexer&) = delete;
 
diff --git a/llvm/lib/MC/MCParser/AsmLexer.cpp b/llvm/lib/MC/MCParser/AsmLexer.cpp
index 0fa7fbdc7b67..99e1df6be6e4 100644
--- a/llvm/lib/MC/MCParser/AsmLexer.cpp
+++ b/llvm/lib/MC/MCParser/AsmLexer.cpp
@@ -11,29 +11,29 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCParser/AsmLexer.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
-#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCParser/AsmLexer.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/SMLoc.h"
-#include "llvm/Support/SaveAndRestore.h"
 #include <cassert>
 #include <cctype>
 #include <cstdio>
 #include <cstring>
-#include <string>
 #include <tuple>
+#include <string>
 #include <utility>
 
 using namespace llvm;
 
-AsmLexer::AsmLexer(const MCAsmInfo &MAI)
-    : MAI(MAI), CurPtr(nullptr), IsAtStartOfLine(true),
-      IsAtStartOfStatement(true), IsParsingMSInlineAsm(false),
-      IsPeeking(false) {
+AsmLexer::AsmLexer(const MCAsmInfo &MAI) : MAI(MAI) {
+  CurPtr = nullptr;
+  IsAtStartOfLine = true;
+  IsAtStartOfStatement = true;
+  IsParsingMSInlineAsm = false;
   AllowAtInIdentifier = !StringRef(MAI.getCommentString()).startswith("@");
 }
 
@@ -487,15 +487,17 @@ StringRef AsmLexer::LexUntilEndOfLine() {
 
 size_t AsmLexer::peekTokens(MutableArrayRef<AsmToken> Buf,
                             bool ShouldSkipSpace) {
-  SaveAndRestore<const char *> SavedTokenStart(TokStart);
-  SaveAndRestore<const char *> SavedCurPtr(CurPtr);
-  SaveAndRestore<bool> SavedAtStartOfLine(IsAtStartOfLine);
-  SaveAndRestore<bool> SavedAtStartOfStatement(IsAtStartOfStatement);
-  SaveAndRestore<bool> SavedSkipSpace(SkipSpace, ShouldSkipSpace);
-  SaveAndRestore<bool> SavedIsPeeking(IsPeeking, true);
+  const char *SavedTokStart = TokStart;
+  const char *SavedCurPtr = CurPtr;
+  bool SavedAtStartOfLine = IsAtStartOfLine;
+  bool SavedAtStartOfStatement = IsAtStartOfStatement;
+  bool SavedSkipSpace = SkipSpace;
+
   std::string SavedErr = getErr();
   SMLoc SavedErrLoc = getErrLoc();
 
+  SkipSpace = ShouldSkipSpace;
+
   size_t ReadCount;
   for (ReadCount = 0; ReadCount < Buf.size(); ++ReadCount) {
     AsmToken Token = LexToken();
@@ -507,6 +509,13 @@ size_t AsmLexer::peekTokens(MutableArrayRef<AsmToken> Buf,
   }
 
   SetError(SavedErrLoc, SavedErr);
+
+  SkipSpace = SavedSkipSpace;
+  IsAtStartOfLine = SavedAtStartOfLine;
+  IsAtStartOfStatement = SavedAtStartOfStatement;
+  CurPtr = SavedCurPtr;
+  TokStart = SavedTokStart;
+
   return ReadCount;
 }
 
@@ -516,7 +525,7 @@ bool AsmLexer::isAtStartOfComment(const char *Ptr) {
   if (CommentString.size() == 1)
     return CommentString[0] == Ptr[0];
 
-  // Allow # preprocessor commments also be counted as comments for "##" cases
+  // FIXME: special case for the bogus "##" comment string in X86MCAsmInfoDarwin
   if (CommentString[1] == '#')
     return CommentString[0] == Ptr[0];
 
@@ -533,7 +542,7 @@ AsmToken AsmLexer::LexToken() {
   // This always consumes at least one character.
   int CurChar = getNextChar();
 
-  if (!IsPeeking && CurChar == '#' && IsAtStartOfStatement) {
+  if (CurChar == '#' && IsAtStartOfStatement) {
     // If this starts with a '#', this may be a cpp
     // hash directive and otherwise a line comment.
     AsmToken TokenBuf[2];
diff --git a/llvm/test/MC/AsmParser/pr28921.s b/llvm/test/MC/AsmParser/pr28921.s
deleted file mode 100644
index 2fbb555f4f3e..000000000000
--- a/llvm/test/MC/AsmParser/pr28921.s
+++ /dev/null
@@ -1,8 +0,0 @@
-// RUN: llvm-mc -triple i386-unknown-unknown %s
-
-# 1 "kernel.S"
-# 1 "<built-in>" 1
-# 1 "kernel.S" 2
-##
-# 10 "kernel.S"
-##