9e51d1f348
`__profd_*` variables are referenced by code only when value profiling is enabled. If disabled (e.g. default -fprofile-instr-generate), the symbols just waste space on ELF/Mach-O. We change the comdat symbol from `__profd_*` to `__profc_*` because an internal symbol does not provide deduplication features on COFF. The choice doesn't matter on ELF. (In -DLLVM_BUILD_INSTRUMENTED_COVERAGE=on build, there is now no `__profd_*` symbols.) On Windows this enables further optimization. We are no longer affected by the link.exe limitation: an external symbol in IMAGE_COMDAT_SELECT_ASSOCIATIVE can cause duplicate definition error. https://lists.llvm.org/pipermail/llvm-dev/2021-May/150758.html We can thus use llvm.compiler.used instead of llvm.used like ELF (D97585). This avoids many `/INCLUDE:` directives in `.drectve`. Here is rnk's measurement for Chrome: ``` This reduced object file size of base_unittests.exe, compiled with coverage, optimizations, and gmlt debug info by 10%: #BEFORE $ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}' 1047758867 $ du -cksh base_unittests.exe 82M base_unittests.exe 82M total # AFTER $ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}' 937886499 $ du -cksh base_unittests.exe 78M base_unittests.exe 78M total ``` The change is NFC for Mach-O. Reviewed By: davidxl, rnk Differential Revision: https://reviews.llvm.org/D103372
27 lines
1.2 KiB
LLVM
27 lines
1.2 KiB
LLVM
; RUN: opt < %s -pgo-instr-gen -instrprof -S | FileCheck %s
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; RUN: opt < %s -passes=pgo-instr-gen,instrprof -S | FileCheck %s
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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$foo = comdat any
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; CHECK: $foo = comdat any
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; CHECK: $__llvm_profile_raw_version = comdat any
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; CHECK: $__profc__stdin__foo.[[#FOO_HASH:]] = comdat any
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@bar = global i32 ()* @foo, align 8
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; CHECK: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
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; CHECK-NOT: __profn__stdin__foo
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; CHECK: @__profc__stdin__foo.[[#FOO_HASH]] = private global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat, align 8
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; CHECK: @__profd__stdin__foo.[[#FOO_HASH]] = private global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 -5640069336071256030, i64 [[#FOO_HASH]], i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__stdin__foo.[[#FOO_HASH]], i32 0, i32 0), i8* null
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; CHECK-NOT: bitcast (i32 ()* @foo to i8*)
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; CHECK-SAME: , i8* null, i32 1, [2 x i16] zeroinitializer }, section "__llvm_prf_data", comdat($__profc__stdin__foo.[[#FOO_HASH]]), align 8
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; CHECK: @__llvm_prf_nm
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; CHECK: @llvm.compiler.used
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define internal i32 @foo() comdat {
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entry:
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ret i32 1
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}
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