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[silgenpattern] Extract out the large completion handler lambda into its own function.

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This makes it easier to read/reason about SILGenPattern::emitSwitchStmt().
This commit is contained in:
Michael Gottesman
2019-03-06 11:30:31 -08:00
parent c8cdc46f02
commit 99c62ea5da
1 changed files with 78 additions and 74 deletions
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152
lib/SILGen/SILGenPattern.cpp
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@@ -2631,6 +2631,81 @@ static void emitDiagnoseOfUnexpectedEnumCase(SILGenFunction &SGF,
SGFContext());
}
static void switchCaseStmtSuccessCallback(SILGenFunction &SGF,
PatternMatchEmission &emission,
ArgArray argArray, ClauseRow &row) {
auto caseBlock = row.getClientData<CaseStmt>();
SGF.emitProfilerIncrement(caseBlock);
// Certain case statements can be entered along multiple paths, either
// because they have multiple labels or because of fallthrough. When we
// need multiple entrance path, we factor the paths with a shared block.
if (!caseBlock->hasBoundDecls()) {
// Don't emit anything yet, we emit it at the cleanup level of the switch
// statement.
JumpDest sharedDest = emission.getSharedCaseBlockDest(caseBlock);
SGF.Cleanups.emitBranchAndCleanups(sharedDest, caseBlock);
return;
}
// If we don't have a fallthrough or a multi-pattern 'case', we can just
// emit the body inline and save some dead blocks. Emit the statement here.
if (!row.hasFallthroughTo() && caseBlock->getCaseLabelItems().size() == 1) {
emission.emitCaseBody(caseBlock);
return;
}
JumpDest sharedDest = emission.getSharedCaseBlockDest(caseBlock);
// Generate the arguments from this row's pattern in the case block's
// expected order, and keep those arguments from being cleaned up, as
// we're passing the +1 along to the shared case block dest. (The
// cleanups still happen, as they are threaded through here messily,
// but the explicit retains here counteract them, and then the
// retain/release pair gets optimized out.)
ArrayRef<CaseLabelItem> labelItems = caseBlock->getCaseLabelItems();
SmallVector<SILValue, 4> args;
SmallVector<VarDecl *, 4> expectedVarOrder;
SmallVector<VarDecl *, 4> vars;
labelItems[0].getPattern()->collectVariables(expectedVarOrder);
row.getCasePattern()->collectVariables(vars);
SILModule &M = SGF.F.getModule();
for (auto expected : expectedVarOrder) {
if (!expected->hasName())
continue;
for (auto *var : vars) {
if (!var->hasName() || var->getName() != expected->getName())
continue;
SILValue value = SGF.VarLocs[var].value;
SILType type = value->getType();
// If we have an address-only type, initialize the temporary
// allocation. We're not going to pass the address as a block
// argument.
if (type.isAddressOnly(M)) {
emission.emitAddressOnlyInitialization(expected, value);
break;
}
// If we have a loadable address, perform a load [copy].
if (type.isAddress()) {
value = SGF.B.emitLoadValueOperation(SGF.CurrentSILLoc, value,
LoadOwnershipQualifier::Copy);
args.push_back(value);
break;
}
value = SGF.B.emitCopyValueOperation(SGF.CurrentSILLoc, value);
args.push_back(value);
break;
}
}
SGF.Cleanups.emitBranchAndCleanups(sharedDest, caseBlock, args);
}
void SILGenFunction::emitSwitchStmt(SwitchStmt *S) {
LLVM_DEBUG(llvm::dbgs() << "emitting switch stmt\n";
S->dump(llvm::dbgs());
@@ -2646,81 +2721,10 @@ void SILGenFunction::emitSwitchStmt(SwitchStmt *S) {
return;
}
auto completionHandler = [&](PatternMatchEmission &emission,
ArgArray argArray,
ClauseRow &row) {
auto caseBlock = row.getClientData<CaseStmt>();
emitProfilerIncrement(caseBlock);
// Certain case statements can be entered along multiple paths, either
// because they have multiple labels or because of fallthrough. When we
// need multiple entrance path, we factor the paths with a shared block.
if (!caseBlock->hasBoundDecls()) {
// Don't emit anything yet, we emit it at the cleanup level of the switch
// statement.
JumpDest sharedDest = emission.getSharedCaseBlockDest(caseBlock);
Cleanups.emitBranchAndCleanups(sharedDest, caseBlock);
return;
}
// If we don't have a fallthrough or a multi-pattern 'case', we can just
// emit the body inline and save some dead blocks. Emit the statement here.
if (!row.hasFallthroughTo() && caseBlock->getCaseLabelItems().size() == 1) {
emission.emitCaseBody(caseBlock);
return;
}
JumpDest sharedDest = emission.getSharedCaseBlockDest(caseBlock);
// Generate the arguments from this row's pattern in the case block's
// expected order, and keep those arguments from being cleaned up, as
// we're passing the +1 along to the shared case block dest. (The
// cleanups still happen, as they are threaded through here messily,
// but the explicit retains here counteract them, and then the
// retain/release pair gets optimized out.)
ArrayRef<CaseLabelItem> labelItems = caseBlock->getCaseLabelItems();
SmallVector<SILValue, 4> args;
SmallVector<VarDecl *, 4> expectedVarOrder;
SmallVector<VarDecl *, 4> vars;
labelItems[0].getPattern()->collectVariables(expectedVarOrder);
row.getCasePattern()->collectVariables(vars);
SILModule &M = F.getModule();
for (auto expected : expectedVarOrder) {
if (!expected->hasName())
continue;
for (auto *var : vars) {
if (!var->hasName() || var->getName() != expected->getName())
continue;
SILValue value = VarLocs[var].value;
SILType type = value->getType();
// If we have an address-only type, initialize the temporary
// allocation. We're not going to pass the address as a block
// argument.
if (type.isAddressOnly(M)) {
emission.emitAddressOnlyInitialization(expected, value);
break;
}
// If we have a loadable address, perform a load [copy].
if (type.isAddress()) {
value = B.emitLoadValueOperation(CurrentSILLoc, value,
LoadOwnershipQualifier::Copy);
args.push_back(value);
break;
}
value = B.emitCopyValueOperation(CurrentSILLoc, value);
args.push_back(value);
break;
}
}
Cleanups.emitBranchAndCleanups(sharedDest, caseBlock, args);
auto completionHandler = [this](PatternMatchEmission &emission,
ArgArray argArray, ClauseRow &row) {
return switchCaseStmtSuccessCallback(*this, emission, argArray, row);
};
PatternMatchEmission emission(*this, S, completionHandler);
// Add a row for each label of each case.