PTH-- Remove feature entirely-
When debugging a boost build with a modified
version of Clang, I discovered that the PTH implementation
stores TokenKind in 8 bits. However, we currently have 368
TokenKinds.
The result is that the value gets truncated and the wrong token
gets picked up when including PTH files. It seems that this will
go wrong every time someone uses a token that uses the 9th bit.
Upon asking on IRC, it was brought up that this was a highly
experimental features that was considered a failure. I discovered
via googling that BoostBuild (mostly Boost.Math) is the only user of
this
feature, using the CC1 flag directly. I believe that this can be
transferred over to normal PCH with minimal effort:
https://github.com/boostorg/build/issues/367
Based on advice on IRC and research showing that this is a nearly
completely unused feature, this patch removes it entirely.
Note: I considered leaving the build-flags in place and making them
emit an error/warning, however since I've basically identified and
warned the only user, it seemed better to just remove them.
Differential Revision: https://reviews.llvm.org/D54547
Change-Id: If32744275ef1f585357bd6c1c813d96973c4d8d9
llvm-svn: 348266
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index e47735e..541dfec 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -31,7 +31,6 @@
#include "clang/Lex/Pragma.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/PreprocessorOptions.h"
-#include "clang/Lex/PTHLexer.h"
#include "clang/Lex/Token.h"
#include "clang/Lex/VariadicMacroSupport.h"
#include "llvm/ADT/ArrayRef.h"
@@ -383,11 +382,6 @@
CurPPLexer->pushConditionalLevel(IfTokenLoc, /*isSkipping*/ false,
FoundNonSkipPortion, FoundElse);
- if (CurPTHLexer) {
- PTHSkipExcludedConditionalBlock();
- return;
- }
-
// Enter raw mode to disable identifier lookup (and thus macro expansion),
// disabling warnings, etc.
CurPPLexer->LexingRawMode = true;
@@ -585,83 +579,6 @@
Tok.getLocation());
}
-void Preprocessor::PTHSkipExcludedConditionalBlock() {
- while (true) {
- assert(CurPTHLexer);
- assert(CurPTHLexer->LexingRawMode == false);
-
- // Skip to the next '#else', '#elif', or #endif.
- if (CurPTHLexer->SkipBlock()) {
- // We have reached an #endif. Both the '#' and 'endif' tokens
- // have been consumed by the PTHLexer. Just pop off the condition level.
- PPConditionalInfo CondInfo;
- bool InCond = CurPTHLexer->popConditionalLevel(CondInfo);
- (void)InCond; // Silence warning in no-asserts mode.
- assert(!InCond && "Can't be skipping if not in a conditional!");
- break;
- }
-
- // We have reached a '#else' or '#elif'. Lex the next token to get
- // the directive flavor.
- Token Tok;
- LexUnexpandedToken(Tok);
-
- // We can actually look up the IdentifierInfo here since we aren't in
- // raw mode.
- tok::PPKeywordKind K = Tok.getIdentifierInfo()->getPPKeywordID();
-
- if (K == tok::pp_else) {
- // #else: Enter the else condition. We aren't in a nested condition
- // since we skip those. We're always in the one matching the last
- // blocked we skipped.
- PPConditionalInfo &CondInfo = CurPTHLexer->peekConditionalLevel();
- // Note that we've seen a #else in this conditional.
- CondInfo.FoundElse = true;
-
- // If the #if block wasn't entered then enter the #else block now.
- if (!CondInfo.FoundNonSkip) {
- CondInfo.FoundNonSkip = true;
-
- // Scan until the eod token.
- CurPTHLexer->ParsingPreprocessorDirective = true;
- DiscardUntilEndOfDirective();
- CurPTHLexer->ParsingPreprocessorDirective = false;
-
- break;
- }
-
- // Otherwise skip this block.
- continue;
- }
-
- assert(K == tok::pp_elif);
- PPConditionalInfo &CondInfo = CurPTHLexer->peekConditionalLevel();
-
- // If this is a #elif with a #else before it, report the error.
- if (CondInfo.FoundElse)
- Diag(Tok, diag::pp_err_elif_after_else);
-
- // If this is in a skipping block or if we're already handled this #if
- // block, don't bother parsing the condition. We just skip this block.
- if (CondInfo.FoundNonSkip)
- continue;
-
- // Evaluate the condition of the #elif.
- IdentifierInfo *IfNDefMacro = nullptr;
- CurPTHLexer->ParsingPreprocessorDirective = true;
- bool ShouldEnter = EvaluateDirectiveExpression(IfNDefMacro).Conditional;
- CurPTHLexer->ParsingPreprocessorDirective = false;
-
- // If this condition is true, enter it!
- if (ShouldEnter) {
- CondInfo.FoundNonSkip = true;
- break;
- }
-
- // Otherwise, skip this block and go to the next one.
- }
-}
-
Module *Preprocessor::getModuleForLocation(SourceLocation Loc) {
if (!SourceMgr.isInMainFile(Loc)) {
// Try to determine the module of the include directive.
@@ -1387,10 +1304,6 @@
///
void Preprocessor::HandleUserDiagnosticDirective(Token &Tok,
bool isWarning) {
- // PTH doesn't emit #warning or #error directives.
- if (CurPTHLexer)
- return CurPTHLexer->DiscardToEndOfLine();
-
// Read the rest of the line raw. We do this because we don't want macros
// to be expanded and we don't require that the tokens be valid preprocessing
// tokens. For example, this is allowed: "#warning ` 'foo". GCC does
@@ -2007,14 +1920,10 @@
if (hadModuleLoaderFatalFailure()) {
// With a fatal failure in the module loader, we abort parsing.
Token &Result = IncludeTok;
- if (CurLexer) {
- Result.startToken();
- CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof);
- CurLexer->cutOffLexing();
- } else {
- assert(CurPTHLexer && "#include but no current lexer set!");
- CurPTHLexer->getEOF(Result);
- }
+ assert(CurLexer && "#include but no current lexer set!");
+ Result.startToken();
+ CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof);
+ CurLexer->cutOffLexing();
}
return;
}