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Merged
nikic merged 2 commits into from
Jun 27, 2025
Merged

[PassBuilder] Treat pipeline aliases as normal passes #146038

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[PassBuilder] Treat pipeline aliases as normal passes
nikic Jun 27, 2025
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nikic Jun 27, 2025
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73 changes: 18 additions & 55 deletions llvm/lib/Passes/PassBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -374,9 +374,6 @@

using namespace llvm;

static const Regex DefaultAliasRegex(
"^(default|thinlto-pre-link|thinlto|lto-pre-link|lto)<(O[0123sz])>$");

cl::opt<bool> llvm::PrintPipelinePasses(
"print-pipeline-passes",
cl::desc("Print a '-passes' compatible string describing the pipeline "
Expand Down Expand Up @@ -618,6 +615,15 @@ static std::optional<OptimizationLevel> parseOptLevel(StringRef S) {
.Default(std::nullopt);
}

static Expected<OptimizationLevel> parseOptLevelParam(StringRef S) {
std::optional<OptimizationLevel> OptLevel = parseOptLevel(S);
if (OptLevel)
return *OptLevel;
return make_error<StringError>(
formatv("invalid optimization level '{}'", S).str(),
inconvertibleErrorCode());
}

Expected<bool> PassBuilder::parseSinglePassOption(StringRef Params,
StringRef OptionName,
StringRef PassName) {
Expand Down Expand Up @@ -1507,13 +1513,6 @@ Expected<bool> parseVirtRegRewriterPassOptions(StringRef Params) {

} // namespace

/// Tests whether a pass name starts with a valid prefix for a default pipeline
/// alias.
static bool startsWithDefaultPipelineAliasPrefix(StringRef Name) {
return Name.starts_with("default") || Name.starts_with("thinlto") ||
Name.starts_with("lto");
}

/// Tests whether registered callbacks will accept a given pass name.
///
/// When parsing a pipeline text, the type of the outermost pipeline may be
Expand All @@ -1535,10 +1534,6 @@ static bool callbacksAcceptPassName(StringRef Name, CallbacksT &Callbacks) {

template <typename CallbacksT>
static bool isModulePassName(StringRef Name, CallbacksT &Callbacks) {
// Manually handle aliases for pre-configured pipeline fragments.
if (startsWithDefaultPipelineAliasPrefix(Name))
return DefaultAliasRegex.match(Name);

StringRef NameNoBracket = Name.take_until([](char C) { return C == '<'; });

// Explicitly handle pass manager names.
Expand Down Expand Up @@ -1737,6 +1732,15 @@ PassBuilder::parsePipelineText(StringRef Text) {
return {std::move(ResultPipeline)};
}

static void setupOptionsForPipelineAlias(PipelineTuningOptions &PTO,
OptimizationLevel L) {
// This is consistent with old pass manager invoked via opt, but
// inconsistent with clang. Clang doesn't enable loop vectorization
// but does enable slp vectorization at Oz.
PTO.LoopVectorization = L.getSpeedupLevel() > 1 && L != OptimizationLevel::Oz;
PTO.SLPVectorization = L.getSpeedupLevel() > 1 && L != OptimizationLevel::Oz;
}

Error PassBuilder::parseModulePass(ModulePassManager &MPM,
const PipelineElement &E) {
auto &Name = E.Name;
Expand Down Expand Up @@ -1789,47 +1793,6 @@ Error PassBuilder::parseModulePass(ModulePassManager &MPM,
;
}

// Manually handle aliases for pre-configured pipeline fragments.
if (startsWithDefaultPipelineAliasPrefix(Name)) {
SmallVector<StringRef, 3> Matches;
if (!DefaultAliasRegex.match(Name, &Matches))
return make_error<StringError>(
formatv("unknown default pipeline alias '{}'", Name).str(),
inconvertibleErrorCode());

assert(Matches.size() == 3 && "Must capture two matched strings!");

OptimizationLevel L = *parseOptLevel(Matches[2]);

// This is consistent with old pass manager invoked via opt, but
// inconsistent with clang. Clang doesn't enable loop vectorization
// but does enable slp vectorization at Oz.
PTO.LoopVectorization =
L.getSpeedupLevel() > 1 && L != OptimizationLevel::Oz;
PTO.SLPVectorization =
L.getSpeedupLevel() > 1 && L != OptimizationLevel::Oz;

if (Matches[1] == "default") {
MPM.addPass(buildPerModuleDefaultPipeline(L));
} else if (Matches[1] == "thinlto-pre-link") {
MPM.addPass(buildThinLTOPreLinkDefaultPipeline(L));
} else if (Matches[1] == "thinlto") {
MPM.addPass(buildThinLTODefaultPipeline(L, nullptr));
} else if (Matches[1] == "lto-pre-link") {
if (PTO.UnifiedLTO)
// When UnifiedLTO is enabled, use the ThinLTO pre-link pipeline. This
// avoids compile-time performance regressions and keeps the pre-link
// LTO pipeline "unified" for both LTO modes.
MPM.addPass(buildThinLTOPreLinkDefaultPipeline(L));
else
MPM.addPass(buildLTOPreLinkDefaultPipeline(L));
} else {
assert(Matches[1] == "lto" && "Not one of the matched options!");
MPM.addPass(buildLTODefaultPipeline(L, nullptr));
}
return Error::success();
}

// Finally expand the basic registered passes from the .inc file.
#define MODULE_PASS(NAME, CREATE_PASS) \
if (Name == NAME) { \
Expand Down
37 changes: 37 additions & 0 deletions llvm/lib/Passes/PassRegistry.def
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Expand Up @@ -240,6 +240,43 @@ MODULE_PASS_WITH_PARAMS(
},
parseStructuralHashPrinterPassOptions, "detailed;call-target-ignored")

MODULE_PASS_WITH_PARAMS(
"default", "", [&](OptimizationLevel L) {
setupOptionsForPipelineAlias(PTO, L);
return buildPerModuleDefaultPipeline(L);
},
parseOptLevelParam, "O0;O1;O2;O3;Os;Oz")
MODULE_PASS_WITH_PARAMS(
"thinlto-pre-link", "", [&](OptimizationLevel L) {
setupOptionsForPipelineAlias(PTO, L);
return buildThinLTOPreLinkDefaultPipeline(L);
},
parseOptLevelParam, "O0;O1;O2;O3;Os;Oz")
MODULE_PASS_WITH_PARAMS(
"thinlto", "", [&](OptimizationLevel L) {
setupOptionsForPipelineAlias(PTO, L);
return buildThinLTODefaultPipeline(L, nullptr);
},
parseOptLevelParam, "O0;O1;O2;O3;Os;Oz")
MODULE_PASS_WITH_PARAMS(
"lto-pre-link", "", [&](OptimizationLevel L) {
setupOptionsForPipelineAlias(PTO, L);
if (PTO.UnifiedLTO) {
// When UnifiedLTO is enabled, use the ThinLTO pre-link pipeline. This
// avoids compile-time performance regressions and keeps the pre-link
// LTO pipeline "unified" for both LTO modes.
return buildThinLTOPreLinkDefaultPipeline(L);
}
return buildLTOPreLinkDefaultPipeline(L);
},
parseOptLevelParam, "O0;O1;O2;O3;Os;Oz")
MODULE_PASS_WITH_PARAMS(
"lto", "", [&](OptimizationLevel L) {
setupOptionsForPipelineAlias(PTO, L);
return buildLTODefaultPipeline(L, nullptr);
},
parseOptLevelParam, "O0;O1;O2;O3;Os;Oz")

#undef MODULE_PASS_WITH_PARAMS

#ifndef CGSCC_ANALYSIS
Expand Down
13 changes: 13 additions & 0 deletions llvm/test/Other/pipeline-alias-errors.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
; RUN: not opt -passes="default" < %s 2>&1 | FileCheck %s --check-prefix=MISSING-OPT-LEVEL
; RUN: not opt -passes="default<foo>" < %s 2>&1 | FileCheck %s --check-prefix=INVALID-OPT-LEVEL
Comment on lines +1 to +2
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@arsenm arsenm Jun 27, 2025

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Check errors with the other names too?

; RUN: not opt -passes="thinlto-pre-link" < %s 2>&1 | FileCheck %s --check-prefix=MISSING-OPT-LEVEL
; RUN: not opt -passes="thinlto-pre-link<foo>" < %s 2>&1 | FileCheck %s --check-prefix=INVALID-OPT-LEVEL
; RUN: not opt -passes="thinlto" < %s 2>&1 | FileCheck %s --check-prefix=MISSING-OPT-LEVEL
; RUN: not opt -passes="thinlto<foo>" < %s 2>&1 | FileCheck %s --check-prefix=INVALID-OPT-LEVEL
; RUN: not opt -passes="lto-pre-link" < %s 2>&1 | FileCheck %s --check-prefix=MISSING-OPT-LEVEL
; RUN: not opt -passes="lto-pre-link<foo>" < %s 2>&1 | FileCheck %s --check-prefix=INVALID-OPT-LEVEL
; RUN: not opt -passes="lto" < %s 2>&1 | FileCheck %s --check-prefix=MISSING-OPT-LEVEL
; RUN: not opt -passes="lto<foo>" < %s 2>&1 | FileCheck %s --check-prefix=INVALID-OPT-LEVEL

; MISSING-OPT-LEVEL: invalid optimization level ''
; INVALID-OPT-LEVEL: invalid optimization level 'foo'