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Differential D33721

[ARM] Add support for target("arm") and target("thumb").
ClosedPublic

Authored by fhahn on May 31 2017, 6:11 AM.

Details

Reviewers
echristo
pcc
kristof.beyls
Commits
rG28f03bbcbb1e: [ARM] Add support for target("arm") and target("thumb").
rC304781: [ARM] Add support for target("arm") and target("thumb").
rL304781: [ARM] Add support for target("arm") and target("thumb").
Summary

This patch adds support for the target("arm") and target("thumb")
attributes, which can be used to force the compiler to generated ARM or
Thumb code for a function.

In LLVM, ARM or Thumb code generation can be controlled by the
thumb-mode target feature. But GCC already uses target("arm") and
target("thumb"), so we have to substitute "arm" with -thumb-mode and
"thumb" with thumb-mode.

Diff Detail

Event Timeline

fhahn created this revision.May 31 2017, 6:11 AM
Herald added subscribers: kristof.beyls, javed.absar, aemerson. · View Herald TranscriptMay 31 2017, 6:11 AM
fhahn added a reviewer: kristof.beyls.May 31 2017, 6:11 AM
javed.absar added a comment.May 31 2017, 6:41 AM
include/clang/Basic/Attr.td
1774 ↗(On Diff #100854)

Would this be a more accurate comment:

"...arm and thumb to thumb-mode" => "arm and thumb to arm-mode or thumb-mode, respectively"
Or
"[-| ] thumb-mode"

fhahn updated this revision to Diff 100880.May 31 2017, 9:41 AM

reworded comment and improved test case to ensure only a single thumb-mode attribute is added.

fhahn marked an inline comment as done.May 31 2017, 9:41 AM
echristo added inline comments.May 31 2017, 1:11 PM
include/clang/Basic/Attr.td
1790–1794 ↗(On Diff #100880)

This is a little painful here - I wonder if we have access to TargetInfo or maybe translate it in the target specific area of the front end? I worry about this sort of thing getting unwieldy.

Thoughts?

Otherwise OK.

fhahn updated this revision to Diff 100994.Jun 1 2017, 3:22 AM

Agreed, ARMTargetInfo is a much better place to do the conversion! Moved attribute conversion to ARMTargetInfo::initFeatureMap. Unfortunately FeaturesVec is const, so creating a mutable clone seemed the most straight-forward thing to do.

fhahn marked an inline comment as done.Jun 1 2017, 3:22 AM
echristo added inline comments.Jun 1 2017, 2:38 PM
lib/Basic/Targets.cpp
5442–5445

Won't work below in handleTargetFeatures?

fhahn added inline comments.Jun 2 2017, 3:19 AM
lib/Basic/Targets.cpp
5442–5445

Unfortunately I don't think so, as it seems like handleTargetFeatures is only called once in TargetInfo::CreateTargetInfo (https://github.com/llvm-mirror/clang/blob/master/lib/Basic/Targets.cpp#L9679
), while initFeatureMap is called for each function and thus can be used to modify the user provided target-features for individual functions (
https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CodeGenModule.cpp#L4426)

ahatanak added a subscriber: ahatanak.Jun 4 2017, 10:38 PM
ahatanak added inline comments.
lib/Basic/Targets.cpp
5447

This can be "else if".

fhahn updated this revision to Diff 101427.Jun 5 2017, 10:13 AM
fhahn marked an inline comment as done.

use else if

echristo accepted this revision.Jun 5 2017, 3:49 PM

Ah right. Thanks for looking.

LGTM.

-eric

This revision is now accepted and ready to land.Jun 5 2017, 3:49 PM
fhahn closed this revision.Jun 6 2017, 2:26 AM

Revision Contents

PathSize
lib/
Basic/
12 lines
test/
CodeGen/
19 lines

Diff 101427

lib/Basic/Targets.cpp

  • This file is larger than 256 KB, so syntax highlighting is disabled by default.
Show First 20 Lines • Show All 5,432 Lines • ▼ Show 20 Lines initFeatureMap(llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags,
// get default Extension features // get default Extension features
unsigned Extensions = llvm::ARM::getDefaultExtensions(CPU, Arch); unsigned Extensions = llvm::ARM::getDefaultExtensions(CPU, Arch);
llvm::ARM::getExtensionFeatures(Extensions, TargetFeatures); llvm::ARM::getExtensionFeatures(Extensions, TargetFeatures);
for (auto Feature : TargetFeatures) for (auto Feature : TargetFeatures)
if (Feature[0] == ' ') if (Feature[0] == ' ')
Features[Feature.drop_front(1)] = true; Features[Feature.drop_front(1)] = true;
return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec); // Convert user-provided arm and thumb GNU target attributes to
// [-| ]thumb-mode target features respectively.
std::vector<std::string> UpdatedFeaturesVec(FeaturesVec);
for (auto &Feature : UpdatedFeaturesVec) {
if (Feature.compare(" arm") == 0)
echristoUnsubmitted
Not Done
ReplyInline Actions

Won't work below in handleTargetFeatures?

echristo: Won't work below in handleTargetFeatures?
fhahnAuthorUnsubmitted
Not Done
ReplyInline Actions

Unfortunately I don't think so, as it seems like handleTargetFeatures is only called once in TargetInfo::CreateTargetInfo (https://github.com/llvm-mirror/clang/blob/master/lib/Basic/Targets.cpp#L9679
), while initFeatureMap is called for each function and thus can be used to modify the user provided target-features for individual functions (
https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CodeGenModule.cpp#L4426)

fhahn: Unfortunately I don't think so, as it seems like `handleTargetFeatures` is only called once in…
Feature = "-thumb-mode";
else if (Feature.compare(" thumb") == 0)
ahatanakUnsubmitted
Done
ReplyInline Actions

This can be "else if".

ahatanak: This can be "else if".
Feature = " thumb-mode";
}
return TargetInfo::initFeatureMap(Features, Diags, CPU, UpdatedFeaturesVec);
} }
bool handleTargetFeatures(std::vector<std::string> &Features, bool handleTargetFeatures(std::vector<std::string> &Features,
DiagnosticsEngine &Diags) override { DiagnosticsEngine &Diags) override {
FPU = 0; FPU = 0;
CRC = 0; CRC = 0;
Crypto = 0; Crypto = 0;
DSP = 0; DSP = 0;
▲ Show 20 Lines • Show All 4,240 Lines • Show Last 20 Lines

test/CodeGen/arm-target-attr.c

  • This file was added.
// RUN: %clang_cc1 -triple thumb-apple-darwin -emit-llvm -o - %s | FileCheck --check-prefix CHECKPOS %s
// RUN: %clang_cc1 -triple thumb-apple-darwin -emit-llvm -o - %s | FileCheck --check-prefix CHECKNEG %s
// RUN: %clang_cc1 -triple arm-apple-darwin -emit-llvm -o - %s | FileCheck --check-prefix CHECKPOS %s
// RUN: %clang_cc1 -triple arm-apple-darwin -emit-llvm -o - %s | FileCheck --check-prefix CHECKNEG %s
__attribute__((target("arm"))) void test_target_arm() {
// CHECKPOS: define void @test_target_arm() [[ARM_ATTRS:#[0-9] ]]
// CHECKNEG: define void @test_target_arm() [[ARM_ATTRS:#[0-9] ]]
}
__attribute__((target("thumb"))) void test_target_thumb() {
// CHECKPOS: define void @test_target_thumb() [[THUMB_ATTRS:#[0-9] ]]
// CHECKNEG: define void @test_target_thumb() [[THUMB_ATTRS:#[0-9] ]]
}
// CHECKPOS: attributes [[ARM_ATTRS]] = { {{.*}} "target-features"="{{.*}}-thumb-mode{{.*}}"
// CHECKPOS: attributes [[THUMB_ATTRS]] = { {{.*}} "target-features"="{{.*}} thumb-mode{{.*}}"
// CHECKNEG-NOT: attributes [[ARM_ATTRS]] = { {{.*}} "target-features"="{{.*}} thumb-mode{{.*}}"
// CHECKNEG-NOT: attributes [[THUMB_ATTRS]] = { {{.*}} "target-features"="{{.*}}-thumb-mode{{.*}}"