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Differential D55291

[gold-plugin] allow function/data sections to be toggleable
ClosedPublic

Authored by nickdesaulniers on Dec 4 2018, 12:53 PM.

Details

Reviewers
pcc
void
Commits
rGc9e38bade5d6: [gold-plugin] allow function/data sections to be toggleable
rL348389: [gold-plugin] allow function/data sections to be toggleable
Summary

r336838 allowed these to be toggleable.
r336858 reverted r336838.
r336943 made the generation of these sections conditional on LDPO_REL.

This commit brings back the toggle-ability. You can specify:
-plugin-opt=-function-sections
-plugin-opt=-data-sections
For your linker flags to disable the changes made in r336943.

Without toggling r336943 off, arm64 linux kernels linked with gold-plugin
see significant boot time regressions, but with r336943 outright reverted
x86_64 linux kernels linked with gold-plugin fail to boot.

Diff Detail

Event Timeline

nickdesaulniers created this revision.Dec 4 2018, 12:53 PM
Herald added a subscriber: llvm-commits. · View Herald TranscriptDec 4 2018, 12:53 PM
Harbormaster completed remote builds in B25689: Diff 176697.Dec 4 2018, 12:53 PM
pcc added a comment.Dec 4 2018, 1:05 PM

The commit message should explain why we are making these toggleable.

nickdesaulniers edited the summary of this revision. (Show Details)Dec 4 2018, 1:12 PM
Herald added subscribers: kristof.beyls, javed.absar. · View Herald TranscriptDec 4 2018, 1:12 PM
nickdesaulniers edited the summary of this revision. (Show Details)Dec 4 2018, 1:12 PM
pcc accepted this revision.Dec 4 2018, 1:53 PM

LGTM with s/r336943/r336838/g and s/r336838/r336943/g in commit message.

This revision is now accepted and ready to land.Dec 4 2018, 1:53 PM
nickdesaulniers edited the summary of this revision. (Show Details)Dec 4 2018, 2:01 PM
Closed by commit rL348389: [gold-plugin] allow function/data sections to be toggleable (authored by nickdesaulniers). · Explain WhyDec 5 2018, 9:49 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
tools/
gold/
6 lines

Diff 176697

tools/gold/gold-plugin.cpp

Show First 20 Lines • Show All 827 Lines • ▼ Show 20 Linesstatic std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
Conf.CPU = options::mcpu; Conf.CPU = options::mcpu;
Conf.Options = InitTargetOptionsFromCodeGenFlags(); Conf.Options = InitTargetOptionsFromCodeGenFlags();
// Disable the new X86 relax relocations since gold might not support them. // Disable the new X86 relax relocations since gold might not support them.
// FIXME: Check the gold version or add a new option to enable them. // FIXME: Check the gold version or add a new option to enable them.
Conf.Options.RelaxELFRelocations = false; Conf.Options.RelaxELFRelocations = false;
// Toggle function/data sections. // Toggle function/data sections.
if (FunctionSections.getNumOccurrences() == 0)
Conf.Options.FunctionSections = SplitSections; Conf.Options.FunctionSections = SplitSections;
if (DataSections.getNumOccurrences() == 0)
Conf.Options.DataSections = SplitSections; Conf.Options.DataSections = SplitSections;
Conf.MAttrs = MAttrs; Conf.MAttrs = MAttrs;
Conf.RelocModel = RelocationModel; Conf.RelocModel = RelocationModel;
Conf.CodeModel = getCodeModel(); Conf.CodeModel = getCodeModel();
Conf.CGOptLevel = getCGOptLevel(); Conf.CGOptLevel = getCGOptLevel();
Conf.DisableVerify = options::DisableVerify; Conf.DisableVerify = options::DisableVerify;
Conf.OptLevel = options::OptLevel; Conf.OptLevel = options::OptLevel;
if (options::Parallelism) if (options::Parallelism)
▲ Show 20 Lines • Show All 268 Lines • Show Last 20 Lines