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[TableGen] Use SmallVectors for preprocessor include stack. NFC. #121571

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Merged
merged 1 commit into from
Jan 3, 2025
Merged

[TableGen] Use SmallVectors for preprocessor include stack. NFC. #121571

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41 changes: 15 additions & 26 deletions llvm/lib/TableGen/TGLexer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -81,8 +81,7 @@ TGLexer::TGLexer(SourceMgr &SM, ArrayRef<std::string> Macros) : SrcMgr(SM) {
TokStart = nullptr;

// Pretend that we enter the "top-level" include file.
PrepIncludeStack.push_back(
std::make_unique<std::vector<PreprocessorControlDesc>>());
PrepIncludeStack.emplace_back();

// Add all macros defined on the command line to the DefinedMacros set.
// Check invalid macro names and print fatal error if we find one.
Expand Down Expand Up @@ -453,8 +452,7 @@ bool TGLexer::LexInclude() {
CurBuf = SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer();
CurPtr = CurBuf.begin();

PrepIncludeStack.push_back(
std::make_unique<std::vector<PreprocessorControlDesc>>());
PrepIncludeStack.emplace_back();
return false;
}

Expand Down Expand Up @@ -656,17 +654,13 @@ tgtok::TokKind TGLexer::LexExclaim() {
bool TGLexer::prepExitInclude(bool IncludeStackMustBeEmpty) {
// Report an error, if preprocessor control stack for the current
// file is not empty.
if (!PrepIncludeStack.back()->empty()) {
if (!PrepIncludeStack.back().empty()) {
prepReportPreprocessorStackError();

return false;
}

// Pop the preprocessing controls from the include stack.
if (PrepIncludeStack.empty()) {
PrintFatalError("preprocessor include stack is empty");
}

PrepIncludeStack.pop_back();

if (IncludeStackMustBeEmpty) {
Expand Down Expand Up @@ -761,7 +755,7 @@ tgtok::TokKind TGLexer::lexPreprocessor(tgtok::TokKind Kind,
// Regardless of whether we are processing tokens or not,
// we put the #ifdef control on stack.
// Note that MacroIsDefined has been canonicalized against ifdef.
PrepIncludeStack.back()->push_back(
PrepIncludeStack.back().push_back(
{tgtok::Ifdef, MacroIsDefined, SMLoc::getFromPointer(TokStart)});

if (!prepSkipDirectiveEnd())
Expand Down Expand Up @@ -789,10 +783,10 @@ tgtok::TokKind TGLexer::lexPreprocessor(tgtok::TokKind Kind,
} else if (Kind == tgtok::Else) {
// Check if this #else is correct before calling prepSkipDirectiveEnd(),
// which will move CurPtr away from the beginning of #else.
if (PrepIncludeStack.back()->empty())
if (PrepIncludeStack.back().empty())
return ReturnError(TokStart, "#else without #ifdef or #ifndef");

PreprocessorControlDesc IfdefEntry = PrepIncludeStack.back()->back();
PreprocessorControlDesc IfdefEntry = PrepIncludeStack.back().back();

if (IfdefEntry.Kind != tgtok::Ifdef) {
PrintError(TokStart, "double #else");
Expand All @@ -801,9 +795,8 @@ tgtok::TokKind TGLexer::lexPreprocessor(tgtok::TokKind Kind,

// Replace the corresponding #ifdef's control with its negation
// on the control stack.
PrepIncludeStack.back()->pop_back();
PrepIncludeStack.back()->push_back(
{Kind, !IfdefEntry.IsDefined, SMLoc::getFromPointer(TokStart)});
PrepIncludeStack.back().back() = {Kind, !IfdefEntry.IsDefined,
SMLoc::getFromPointer(TokStart)};

if (!prepSkipDirectiveEnd())
return ReturnError(CurPtr, "only comments are supported after #else");
Expand All @@ -822,10 +815,10 @@ tgtok::TokKind TGLexer::lexPreprocessor(tgtok::TokKind Kind,
} else if (Kind == tgtok::Endif) {
// Check if this #endif is correct before calling prepSkipDirectiveEnd(),
// which will move CurPtr away from the beginning of #endif.
if (PrepIncludeStack.back()->empty())
if (PrepIncludeStack.back().empty())
return ReturnError(TokStart, "#endif without #ifdef");

auto &IfdefOrElseEntry = PrepIncludeStack.back()->back();
auto &IfdefOrElseEntry = PrepIncludeStack.back().back();

if (IfdefOrElseEntry.Kind != tgtok::Ifdef &&
IfdefOrElseEntry.Kind != tgtok::Else) {
Expand All @@ -836,7 +829,7 @@ tgtok::TokKind TGLexer::lexPreprocessor(tgtok::TokKind Kind,
if (!prepSkipDirectiveEnd())
return ReturnError(CurPtr, "only comments are supported after #endif");

PrepIncludeStack.back()->pop_back();
PrepIncludeStack.back().pop_back();

// If we were processing tokens before this #endif, then
// we should continue it.
Expand Down Expand Up @@ -1055,20 +1048,16 @@ bool TGLexer::prepSkipDirectiveEnd() {
}

bool TGLexer::prepIsProcessingEnabled() {
for (const PreprocessorControlDesc &I :
llvm::reverse(*PrepIncludeStack.back()))
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@mshockwave mshockwave Jan 3, 2025

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I have no idea why it was using llvm::reverse here. Maybe the last element usually has a higher chance to bail out?

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@jayfoad jayfoad Jan 3, 2025

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I did think about that, but really if you have nested #ifs I don't see any reason why the inner (or outer) condition would have a higher chance of being false.

if (!I.IsDefined)
return false;

return true;
return all_of(PrepIncludeStack.back(),
[](const PreprocessorControlDesc &I) { return I.IsDefined; });
}

void TGLexer::prepReportPreprocessorStackError() {
if (PrepIncludeStack.back()->empty())
if (PrepIncludeStack.back().empty())
PrintFatalError("prepReportPreprocessorStackError() called with "
"empty control stack");

auto &PrepControl = PrepIncludeStack.back()->back();
auto &PrepControl = PrepIncludeStack.back().back();
PrintError(CurBuf.end(), "reached EOF without matching #endif");
PrintError(PrepControl.SrcPos, "the latest preprocessor control is here");

Expand Down
5 changes: 2 additions & 3 deletions llvm/lib/TableGen/TGLexer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#ifndef LLVM_LIB_TABLEGEN_TGLEXER_H
#define LLVM_LIB_TABLEGEN_TGLEXER_H

#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/DataTypes.h"
Expand All @@ -21,7 +22,6 @@
#include <memory>
#include <set>
#include <string>
#include <vector>

namespace llvm {
template <typename T> class ArrayRef;
Expand Down Expand Up @@ -323,8 +323,7 @@ class TGLexer {
// preprocessing control stacks for the current file and all its
// parent files. The back() element is the preprocessing control
// stack for the current file.
std::vector<std::unique_ptr<std::vector<PreprocessorControlDesc>>>
PrepIncludeStack;
SmallVector<SmallVector<PreprocessorControlDesc>> PrepIncludeStack;

// Validate that the current preprocessing control stack is empty,
// since we are about to exit a file, and pop the include stack.
Expand Down
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