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[Clang][Driver] Skip empty strings in getAArch64MultilibFlags #97827

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Merged
merged 2 commits into from
Jul 11, 2024
Merged

[Clang][Driver] Skip empty strings in getAArch64MultilibFlags #97827

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81d77bf
[Clang][Driver] Skip empty strings in getAArch64MultilibFlags
statham-arm Jul 5, 2024
7179fc7
fixup! [Clang][Driver] Skip empty strings in getAArch64MultilibFlags
statham-arm Jul 8, 2024
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20 changes: 12 additions & 8 deletions clang/lib/Driver/ToolChain.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -195,11 +195,13 @@ static void getAArch64MultilibFlags(const Driver &D,
UnifiedFeatures.end());
std::vector<std::string> MArch;
for (const auto &Ext : AArch64::Extensions)
if (FeatureSet.contains(Ext.PosTargetFeature))
MArch.push_back(Ext.UserVisibleName.str());
if (!Ext.UserVisibleName.empty())
if (FeatureSet.contains(Ext.PosTargetFeature))
MArch.push_back(Ext.UserVisibleName.str());
for (const auto &Ext : AArch64::Extensions)
if (FeatureSet.contains(Ext.NegTargetFeature))
MArch.push_back(("no" + Ext.UserVisibleName).str());
if (!Ext.UserVisibleName.empty())
if (FeatureSet.contains(Ext.NegTargetFeature))
MArch.push_back(("no" + Ext.UserVisibleName).str());
StringRef ArchName;
for (const auto &ArchInfo : AArch64::ArchInfos)
if (FeatureSet.contains(ArchInfo->ArchFeature))
Expand All @@ -221,11 +223,13 @@ static void getARMMultilibFlags(const Driver &D,
UnifiedFeatures.end());
std::vector<std::string> MArch;
for (const auto &Ext : ARM::ARCHExtNames)
if (FeatureSet.contains(Ext.Feature))
MArch.push_back(Ext.Name.str());
if (!Ext.Name.empty())
if (FeatureSet.contains(Ext.Feature))
MArch.push_back(Ext.Name.str());
for (const auto &Ext : ARM::ARCHExtNames)
if (FeatureSet.contains(Ext.NegFeature))
MArch.push_back(("no" + Ext.Name).str());
if (!Ext.Name.empty())
if (FeatureSet.contains(Ext.NegFeature))
MArch.push_back(("no" + Ext.Name).str());
MArch.insert(MArch.begin(), ("-march=" + Triple.getArchName()).str());
Result.push_back(llvm::join(MArch, "+"));

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17 changes: 17 additions & 0 deletions clang/test/Driver/aarch64-multilib-rcpc3.c
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@@ -0,0 +1,17 @@
// RUN: %clang --target=aarch64-none-elf -march=armv8.9-a+rcpc3 -print-multi-flags-experimental -c %s 2>&1 | FileCheck %s

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I think it could be worth a comment here explaining what the test is checking for as it would likely need git blame to work it out otherwise. For example:

// rcpc3 implies rcpc-immo which does not have a user-visible name, check that an empty string is not produced.

// The purpose of this regression test is to make sure that when
// compile options are converted into multilib selection flags, no
// empty strings are accidentally included in the
// -march=armv8.9-a+foo+bar+baz string, leading to two consecutive +
// signs. With +rcpc3 in the input, this used to generate an empty
// string for the anonymous architecture extension corresponding to
// the SubtargetFeature 'rcpc-immo', which is a dependency of rcpc3
// but has no separate extension name for use on command lines. So we
// check that the two named rcpc options appear, and that no ++
// appears before or after.

// CHECK: -march=armv8.9-a
// CHECK-NOT: ++
// CHECK-SAME: +rcpc+rcpc3+
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I'm wondering if a CHECK-NOT ++ could be used as well. This test might unexpectedly pass if the ordering of the features were changed.

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Done. I wasn't sure whether it would need to come before or after the rcpc+rcpc3 check. The answer turns out to be both.

// CHECK-NOT: ++
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