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Differential D19410

[scan-build] fix warnings emitted on LLVM ARM code base
ClosedPublic

Authored by apelete on Apr 22 2016, 7:45 AM.

Details

Reviewers
rengolin
grosbach
compnerd
MatzeB
Summary

Fix "Logic error" warnings of the type "Called C++ object pointer is
null" reported by Clang Static Analyzer on the following files:

  • lib/Target/ARM/AsmParser/ARMAsmParser.cpp,
  • lib/Target/ARM/Thumb2SizeReduction.cpp.

Signed-off-by: Apelete Seketeli <apelete@seketeli.net>

Diff Detail

Event Timeline

apelete updated this revision to Diff 54648.Apr 22 2016, 7:45 AM
apelete retitled this revision from to [scan-build] fix logic error warnings emitted on llvm code base.
apelete added reviewers: rengolin, • tstellarAMD, pcc, atrick.
apelete updated this object.
apelete added a subscriber: llvm-commits.
Herald added subscribers: mzolotukhin, arsenm, aemerson. · View Herald TranscriptApr 22 2016, 7:45 AM
• tstellarAMD added inline comments.Apr 22 2016, 7:54 AM
lib/Target/AMDGPU/SIInstrInfo.cpp
1867–1870 ↗(On Diff #54648)

A better fix would be move this if block to the top of the function before the first use of DefinedRC.

apelete added inline comments.Apr 22 2016, 8:21 AM
lib/Target/AMDGPU/SIInstrInfo.cpp
1867–1870 ↗(On Diff #54648)

This is what I wanted to do in the first place, but I wondered if doing the check and returning early would still give a correct result; I wasn't sure about the impact it would have had on the logic of the function :-).

Will fix this, thanks for your review.

apelete updated this revision to Diff 54662.Apr 22 2016, 8:50 AM

[scan-build] fix logic error warnings emitted on llvm code base

Following changes were done since last revision:

  • lib/Target/AMDGPU/SIInstrInfo.cpp: check DefineRC early and return if operand expects an immediate value.
apelete marked 2 inline comments as done.Apr 22 2016, 8:52 AM
• tstellarAMD added inline comments.Apr 25 2016, 7:07 AM
lib/Target/AMDGPU/SIInstrInfo.cpp
1839 ↗(On Diff #54662)

Looking at this again. I think this should return !MO.isReg() and it should be moved below

if (!MO)

MO = &MI->getOperand(OpIdx);

Sorry I missed this the first time.

apelete updated this revision to Diff 54867.Apr 25 2016, 9:24 AM

[scan-build] fix logic error warnings emitted on llvm code base

Changes since last revision:

  • check TargetRegisterClass variable value after MachineOperand initialization and return based on the kind of MachineOperand.
apelete marked an inline comment as done.Apr 25 2016, 9:29 AM
apelete added inline comments.
lib/Target/AMDGPU/SIInstrInfo.cpp
1839 ↗(On Diff #54867)

Thanks for looking at it again.

apelete updated this revision to Diff 55750.May 1 2016, 9:34 AM
apelete marked an inline comment as done.

[scan-build] fix logic error warnings emitted on llvm code base

Changes since last revision:

  • fast forward rebase on git master branch.
apelete added a comment.May 1 2016, 10:06 AM

Waiting for review, could someone please have a look at this one ?

• tstellarAMD edited edge metadata.May 2 2016, 7:16 AM

The AMDGPU changes look OK to me. If you want to commit those in a separate patch, that's fine with me.

apelete added a comment.May 2 2016, 9:29 AM
In D19410#418545, @tstellarAMD wrote:

The AMDGPU changes look OK to me. If you want to commit those in a separate patch, that's fine with me.

Ok, I'm going to split AMDGPU changes into a separate patch, hoping it will help speeding up the landing in trunk.
I'll need your help to check it in for me though :-).

Thanks.

apelete updated this revision to Diff 55834.May 2 2016, 9:35 AM
apelete edited edge metadata.

[scan-build] fix logic error warnings emitted on llvm code base

Changes since last revision:

  • split changes in lib/Target/AMDGPU/SIInstrInfo.cpp into a separate patch.
apelete updated this revision to Diff 56264.May 5 2016, 4:36 AM

[scan-build] fix warnings emitted on LLVM ARM code base

Changes since last revision:

  • split patch into ARM changes unit to ease review process,
  • cherry-pick ARM changes from D19498.
apelete retitled this revision from [scan-build] fix logic error warnings emitted on llvm code base to [scan-build] fix warnings emitted on LLVM ARM code base.May 5 2016, 4:38 AM
apelete updated this object.
apelete edited reviewers, added: compnerd, grosbach, MatzeB; removed: • tstellarAMD, atrick, pcc.
rengolin added a subscriber: weimingz.May 5 2016, 4:48 AM
rengolin added inline comments.
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Better ask @weimingz about this one.

lib/Target/ARM/AsmParser/ARMAsmParser.cpp
9965

We don't want asserts in assembly parsers, people can write pretty much anything. Make this an error.

lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp
409 ↗(On Diff #56264)

probably better if you do:

if (A && A-getVariable()) {
lib/Target/ARM/Thumb2SizeReduction.cpp
992

this assert is in the wrong place. It should be just after BundleMI is created.

compnerd added inline comments.May 5 2016, 9:02 AM
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Ugh, this is *subtle*. If we are going to simplify this, please add a couple of asserts.

assert(requiresRegisterScavenging() && "ARM requires register scavenging");
assert(RS && "Target requiring register scavenging not provided register scavenger");
lib/Target/ARM/AsmParser/ARMAsmParser.cpp
9965

Yes, adding an error here would be reasonable, however, if we do that, please add a test case that demonstrates the invalid input. I believe that the assertion here is valid as we will always have a section (even if the user inserts it in the wrong location, theres the implicit initial text section to which we will refer).

rengolin added inline comments.May 5 2016, 9:11 AM
lib/Target/ARM/AsmParser/ARMAsmParser.cpp
9965

If not having a section here is an assembler error, not an assembly error, than asserting is fine. Users should never see this.

weimingz added inline comments.May 5 2016, 10:52 AM
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Agree. We need to simplify the BigStack test. It's hard to read.

It would be better if we refactor it to:

unsigned EstimatedStackSize = MFI->estimateStackSize(MF) + ...

bool BgsTack = EstimatedStackSize >= estimatedRSStackSizeLImit() || ... || ...

apelete mentioned this in D19498: [scan-build] fix logic error warnings emitted on llvm code base.May 5 2016, 4:07 PM
rengolin added inline comments.May 6 2016, 7:20 AM
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Weiming, can you do this one once you re-commit your patch?

weimingz added inline comments.May 6 2016, 9:52 AM
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Sure. I will do.

weimingz added inline comments.May 6 2016, 2:04 PM
lib/Target/ARM/ARMFrameLowering.cpp
1610 ↗(On Diff #56264)

Please review http://reviews.llvm.org/D19896

apelete updated this revision to Diff 56543.May 9 2016, 3:19 AM

[scan-build] fix warnings emitted on LLVM ARM code base

Changes since last revision:

  • lib/Target/ARM/ARMFrameLowering.cpp: removed changes, fix is done in D19896.
Herald added a subscriber: rengolin. · View Herald TranscriptMay 9 2016, 3:19 AM
rengolin edited edge metadata.May 9 2016, 3:32 AM

Please, change the two conditions and remove the two asserts I commented on.

cheers,
--renato

lib/Target/ARM/AsmParser/ARMAsmParser.cpp
9965

I agree, this assert is correct.

lib/Target/ARM/Thumb2SizeReduction.cpp
992

turns out I was wrong. This cannot be an assert, as it doesn't have to break when BuidleMI is not defined.

Please change the condition to:

if (BundleMI && !NextInSameBundle && MI->isInsideBundle()) {
apelete updated this revision to Diff 56549.May 9 2016, 4:12 AM
apelete edited edge metadata.

[scan-build] fix warnings emitted on LLVM ARM code base

Changes since last revision:

  • lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp: remove asert and check against value MCSymbol pointer and existence of variable value within MCSymbol,
  • lib/Target/ARM/Thumb2SizeReduction.cpp: remove assert since BundleMI processing should continue if BundleMI is nullptr.
apelete updated this object.May 9 2016, 4:14 AM
rengolin accepted this revision.May 10 2016, 10:30 AM
rengolin edited edge metadata.

Thanks Apelete,

Assuming this change passes "make check-all", I'm happy with them.

cheers,
--renato

This revision is now accepted and ready to land.May 10 2016, 10:30 AM
apelete updated this revision to Diff 56857.EditedMay 11 2016, 1:05 AM
apelete edited edge metadata.

[scan-build] fix warnings emitted on LLVM ARM code base

Changes since last revision:

  • lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp: remove the changes in this file since they break the following tests:

    Failing Tests (25):
    • LLVM :: CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
    • LLVM :: CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
    • LLVM :: CodeGen/ARM/debug-info-blocks.ll
    • LLVM :: CodeGen/ARM/debug-info-sreg2.ll
    • LLVM :: CodeGen/ARM/local-call.ll
    • LLVM :: CodeGen/ARM/none-macho.ll
    • LLVM :: CodeGen/ARM/thumb1-varalloc.ll
    • LLVM :: CodeGen/Thumb2/constant-islands.ll
    • LLVM :: DebugInfo/ARM/bitfield.ll
    • LLVM :: DebugInfo/ARM/s-super-register.ll
    • LLVM :: DebugInfo/ARM/split-complex.ll
    • LLVM :: LTO/ARM/runtime-library-subtarget.ll
    • LLVM :: MC/ARM/aligned-blx.s
    • LLVM :: MC/ARM/macho-movwt.s
    • LLVM :: MC/ARM/misaligned-blx.s
    • LLVM :: MC/ARM/thumb1-relax-br.s
    • LLVM :: MC/ARM/tls-directives.s
    • LLVM :: MC/MachO/ARM/aliased-symbols.s
    • LLVM :: MC/MachO/ARM/compact-unwind-armv7k.s
    • LLVM :: MC/MachO/ARM/darwin-ARM-reloc.s
    • LLVM :: MC/MachO/ARM/darwin-Thumb-reloc.s
    • LLVM :: MC/MachO/ARM/long-call-branch-island-relocation.s
    • LLVM :: MC/MachO/ARM/static-movt-relocs.s
    • LLVM :: MC/MachO/ARM/thumb-bl-jbits.s
    • LLVM :: MC/MachO/ARM/thumb2-movw-fixup.s
apelete added a comment.May 11 2016, 1:10 AM
In D19410#425989, @rengolin wrote:

Thanks Apelete,

Assuming this change passes "make check-all", I'm happy with them.

I removed some of the changes that seem to break the unit tests and I'll look into why when I get some time.
In the meantime, if the remaining changes look OK to you please go on and commit for me as I don't have commit access.

apelete updated this object.May 11 2016, 1:11 AM
rengolin closed this revision.May 12 2016, 5:40 AM

Current changes in as r269285. Thanks!

Please open a new revision for any future changes.

Revision Contents

PathSize
lib/
Target/
ARM/
AsmParser/
4 lines
2 lines

Diff 56857

lib/Target/ARM/AsmParser/ARMAsmParser.cpp

  • This file is larger than 256 KB, so syntax highlighting is disabled by default.
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/// ::= .align /// ::= .align
bool ARMAsmParser::parseDirectiveAlign(SMLoc L) { bool ARMAsmParser::parseDirectiveAlign(SMLoc L) {
// NOTE: if this is not the end of the statement, fall back to the target // NOTE: if this is not the end of the statement, fall back to the target
// agnostic handling for this directive which will correctly handle this. // agnostic handling for this directive which will correctly handle this.
if (getLexer().isNot(AsmToken::EndOfStatement)) if (getLexer().isNot(AsmToken::EndOfStatement))
return true; return true;
// '.align' is target specifically handled to mean 2**2 byte alignment. // '.align' is target specifically handled to mean 2**2 byte alignment.
if (getStreamer().getCurrentSection().first->UseCodeAlign()) const MCSection *Section = getStreamer().getCurrentSection().first;
assert(Section && "must have section to emit alignment");
rengolinUnsubmitted
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We don't want asserts in assembly parsers, people can write pretty much anything. Make this an error.

rengolin: We don't want asserts in assembly parsers, people can write pretty much anything. Make this an…
compnerdUnsubmitted
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Yes, adding an error here would be reasonable, however, if we do that, please add a test case that demonstrates the invalid input. I believe that the assertion here is valid as we will always have a section (even if the user inserts it in the wrong location, theres the implicit initial text section to which we will refer).

compnerd: Yes, adding an error here would be reasonable, however, if we do that, please add a test case…
rengolinUnsubmitted
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If not having a section here is an assembler error, not an assembly error, than asserting is fine. Users should never see this.

rengolin: If not having a section here is an assembler error, not an assembly error, than asserting is…
rengolinUnsubmitted
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I agree, this assert is correct.

rengolin: I agree, this assert is correct.
if (Section->UseCodeAlign())
getStreamer().EmitCodeAlignment(4, 0); getStreamer().EmitCodeAlignment(4, 0);
else else
getStreamer().EmitValueToAlignment(4, 0, 1, 0); getStreamer().EmitValueToAlignment(4, 0, 1, 0);
return false; return false;
} }
/// parseDirectiveThumbSet /// parseDirectiveThumbSet
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lib/Target/ARM/Thumb2SizeReduction.cpp

Show First 20 Lines • Show All 982 Lines • ▼ Show 20 Lines if (ReduceMI(MBB, MI, LiveCPSR, IsSelfLoop)) {
MachineBasicBlock::instr_iterator I = std::prev(NextMII); MachineBasicBlock::instr_iterator I = std::prev(NextMII);
MI = &*I; MI = &*I;
// Removing and reinserting the first instruction in a bundle will break // Removing and reinserting the first instruction in a bundle will break
// up the bundle. Fix the bundling if it was broken. // up the bundle. Fix the bundling if it was broken.
if (NextInSameBundle && !NextMII->isBundledWithPred()) if (NextInSameBundle && !NextMII->isBundledWithPred())
NextMII->bundleWithPred(); NextMII->bundleWithPred();
} }
if (!NextInSameBundle && MI->isInsideBundle()) { if (BundleMI && !NextInSameBundle && MI->isInsideBundle()) {
// FIXME: Since post-ra scheduler operates on bundles, the CPSR kill // FIXME: Since post-ra scheduler operates on bundles, the CPSR kill
rengolinUnsubmitted
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this assert is in the wrong place. It should be just after BundleMI is created.

rengolin: this assert is in the wrong place. It should be just after BundleMI is created.
rengolinUnsubmitted
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turns out I was wrong. This cannot be an assert, as it doesn't have to break when BuidleMI is not defined.

Please change the condition to:

if (BundleMI && !NextInSameBundle && MI->isInsideBundle()) {
rengolin: turns out I was wrong. This cannot be an assert, as it doesn't have to break when BuidleMI is…
// marker is only on the BUNDLE instruction. Process the BUNDLE // marker is only on the BUNDLE instruction. Process the BUNDLE
// instruction as we finish with the bundled instruction to work around // instruction as we finish with the bundled instruction to work around
// the inconsistency. // the inconsistency.
if (BundleMI->killsRegister(ARM::CPSR)) if (BundleMI->killsRegister(ARM::CPSR))
LiveCPSR = false; LiveCPSR = false;
MachineOperand *MO = BundleMI->findRegisterDefOperand(ARM::CPSR); MachineOperand *MO = BundleMI->findRegisterDefOperand(ARM::CPSR);
if (MO && !MO->isDead()) if (MO && !MO->isDead())
LiveCPSR = true; LiveCPSR = true;
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