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[CodeCompletion] Reduce accumulating memory per fast completion #28904

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Merged
merged 2 commits into from
Jan 14, 2020
Merged

[CodeCompletion] Reduce accumulating memory per fast completion #28904

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8f38105
[CodeCompletion] Reduce leaking memory per fast completion
rintaro Dec 20, 2019
108b9c3
[CodeCompletion] Open virtual file for fast completion buffers
rintaro Jan 2, 2020
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51 changes: 41 additions & 10 deletions lib/IDE/CompletionInstance.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include "swift/Basic/SourceManager.h"
#include "swift/Driver/FrontendUtil.h"
#include "swift/Frontend/Frontend.h"
#include "swift/Parse/Lexer.h"
#include "swift/Parse/PersistentParserState.h"
#include "swift/Subsystems.h"
#include "llvm/ADT/Hashing.h"
Expand Down Expand Up @@ -159,27 +160,27 @@ bool CompletionInstance::performCachedOperaitonIfPossible(
if (oldInfo.Kind != CodeCompletionDelayedDeclKind::FunctionBody)
return false;

auto newBufferID = SM.addMemBufferCopy(completionBuffer);
SM.setCodeCompletionPoint(newBufferID, Offset);

// Parse the new buffer into temporary SourceFile.
SourceManager tmpSM;
auto tmpBufferID = tmpSM.addMemBufferCopy(completionBuffer);
tmpSM.setCodeCompletionPoint(tmpBufferID, Offset);

LangOptions langOpts;
langOpts.DisableParserLookup = true;
TypeCheckerOptions typeckOpts;
SearchPathOptions searchPathOpts;
DiagnosticEngine Diags(SM);
DiagnosticEngine tmpDiags(tmpSM);
std::unique_ptr<ASTContext> Ctx(
ASTContext::get(langOpts, typeckOpts, searchPathOpts, SM, Diags));
ASTContext::get(langOpts, typeckOpts, searchPathOpts, tmpSM, tmpDiags));
registerIDERequestFunctions(Ctx->evaluator);
registerTypeCheckerRequestFunctions(Ctx->evaluator);
ModuleDecl *M = ModuleDecl::create(Identifier(), *Ctx);
unsigned BufferID = SM.getCodeCompletionBufferID();
PersistentParserState newState;
SourceFile *newSF =
new (*Ctx) SourceFile(*M, SourceFileKind::Library, BufferID,
new (*Ctx) SourceFile(*M, SourceFileKind::Library, tmpBufferID,
SourceFile::ImplicitModuleImportKind::None);
newSF->enableInterfaceHash();
parseIntoSourceFileFull(*newSF, BufferID, &newState);
parseIntoSourceFileFull(*newSF, tmpBufferID, &newState);
// Couldn't find any completion token?
if (!newState.hasCodeCompletionDelayedDeclState())
return false;
Expand Down Expand Up @@ -208,6 +209,36 @@ bool CompletionInstance::performCachedOperaitonIfPossible(
// OK, we can perform fast completion for this. Update the orignal delayed
// decl state.

// Fast completion keeps the buffer in memory for multiple completions.
// To reduce the consumption, slice the source buffer so it only holds
// the portion that is needed for the second pass.
auto startOffset = newInfo.StartOffset;
if (newInfo.PrevOffset != ~0u)
startOffset = newInfo.PrevOffset;
auto startLoc = tmpSM.getLocForOffset(tmpBufferID, startOffset);
startLoc = Lexer::getLocForStartOfLine(tmpSM, startLoc);
startOffset = tmpSM.getLocOffsetInBuffer(startLoc, tmpBufferID);

auto endOffset = newInfo.EndOffset;
auto endLoc = tmpSM.getLocForOffset(tmpBufferID, endOffset);
endLoc = Lexer::getLocForEndOfToken(tmpSM, endLoc);
endOffset = tmpSM.getLocOffsetInBuffer(endLoc, tmpBufferID);

newInfo.StartOffset -= startOffset;
newInfo.EndOffset -= startOffset;
if (newInfo.PrevOffset != ~0u)
newInfo.PrevOffset -= startOffset;

auto sourceText = completionBuffer->getBuffer().slice(startOffset, endOffset);
auto newOffset = Offset - startOffset;

auto newBufferID =
SM.addMemBufferCopy(sourceText, completionBuffer->getBufferIdentifier());
SM.openVirtualFile(SM.getLocForBufferStart(newBufferID),
tmpSM.getDisplayNameForLoc(startLoc),
tmpSM.getLineAndColumn(startLoc).first - 1);
SM.setCodeCompletionPoint(newBufferID, newOffset);

// Construct dummy scopes. We don't need to restore the original scope
// because they are probably not 'isResolvable()' anyway.
auto &SI = oldState.getScopeInfo();
Expand All @@ -227,8 +258,8 @@ bool CompletionInstance::performCachedOperaitonIfPossible(
if (DiagC)
CI.addDiagnosticConsumer(DiagC);

CI.getDiags().diagnose(SM.getLocForOffset(BufferID, newInfo.StartOffset),
diag::completion_reusing_astcontext);
CI.getDiags().diagnose(SM.getLocForOffset(newBufferID, newInfo.StartOffset),
diag::completion_reusing_astcontext);

Callback(CI);

Expand Down