850592ec14
This was based off @thakis' draft in {D103517}. I employed templates to ensure
the support for `-why_live` wouldn't slow down the regular non-why-live code
path.
No stat sig perf difference on my 3.2 GHz 16-Core Intel Xeon W:
base diff difference (95% CI)
sys_time 1.195 ± 0.015 1.199 ± 0.022 [ -0.4% .. +1.0%]
user_time 3.716 ± 0.022 3.701 ± 0.025 [ -0.7% .. -0.1%]
wall_time 4.606 ± 0.034 4.597 ± 0.046 [ -0.6% .. +0.2%]
samples 44 37
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D120377
65 lines
1.6 KiB
ArmAsm
65 lines
1.6 KiB
ArmAsm
# REQUIRES: x86
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos %s -o %t.o
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# RUN: %lld -lSystem -dead_strip -why_live _foo -why_live _undef -U _undef \
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# RUN: -why_live _support -why_live _support_refs_dylib_fun \
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# RUN: -why_live _abs %t.o -o /dev/null 2>&1 | FileCheck %s
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## Due to an implementation detail, LLD is not able to report -why_live info for
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## absolute symbols. (ld64 has the same shortcoming.)
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# CHECK-NOT: _abs
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# CHECK: _foo from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _quux from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _undef from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _main from {{.*}}why-live.s.tmp.o
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## Our handling of live_support sections can be improved... we should print the
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## dylib symbol that keeps _support_refs_dylib_fun alive, instead of printing
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## the live_support symbol's name itself. (ld64 seems to have the same issue.)
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# CHECK-NEXT: _support_refs_dylib_fun from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _support_refs_dylib_fun from {{.*}}why-live.s.tmp.o
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## Again, this can be improved: we shouldn't be printing _support twice. (ld64
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## seems to have the same issue.)
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# CHECK-NEXT: _support from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _support from {{.*}}why-live.s.tmp.o
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# CHECK-NEXT: _foo from {{.*}}why-live.s.tmp.o
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# CHECK-EMPTY:
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.text
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_foo:
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retq
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_bar:
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retq
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_baz:
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callq _foo
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retq
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.no_dead_strip _quux
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_quux:
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callq _foo
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retq
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.globl _main
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_main:
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callq _foo
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callq _baz
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callq _undef
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callq ___isnan
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retq
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.globl _abs
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_abs = 0x1000
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.section __TEXT,support,regular,live_support
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_support:
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callq _foo
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callq _abs
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retq
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_support_refs_dylib_fun:
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callq ___isnan
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retq
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.subsections_via_symbols
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