From: Reid Kleckner Date: Mon, 16 Sep 2019 18:49:09 +0000 (+0000) Subject: [PGO] Use linkonce_odr linkage for __profd_ variables in comdat groups X-Git-Tag: llvmorg-11-init~9102 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=32837a0c93ecdb33faaba253c5c7e868db9c529f;p=platform%2Fupstream%2Fllvm.git [PGO] Use linkonce_odr linkage for __profd_ variables in comdat groups This fixes relocations against __profd_ symbols in discarded sections, which is PR41380. In general, instrumentation happens very early, and optimization and inlining happens afterwards. The counters for a function are calculated early, and after inlining, counters for an inlined function may be widely referenced by other functions. For C++ inline functions of all kinds (linkonce_odr & available_externally mainly), instr profiling wants to deduplicate these __profc_ and __profd_ globals. Otherwise the binary would be quite large. I made __profd_ and __profc_ comdat in r355044, but I chose to make __profd_ internal. At the time, I was only dealing with coverage, and in that case, none of the instrumentation needs to reference __profd_. However, if you use PGO, then instrumentation passes add calls to __llvm_profile_instrument_range which reference __profd_ globals. The solution is to make these globals externally visible by using linkonce_odr linkage for data as was done for counters. This is safe because PGO adds a CFG hash to the names of the data and counter globals, so if different TUs have different globals, they will get different data and counter arrays. Reviewers: xur, hans Differential Revision: https://reviews.llvm.org/D67579 llvm-svn: 372020 --- diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp index a21604a..65773bb 100644 --- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp +++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp @@ -740,9 +740,8 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) { PD = It->second; } - // Match the linkage and visibility of the name global, except on COFF, where - // the linkage must be local and consequentially the visibility must be - // default. + // Match the linkage and visibility of the name global. COFF supports using + // comdats with internal symbols, so do that if we can. Function *Fn = Inc->getParent()->getParent(); GlobalValue::LinkageTypes Linkage = NamePtr->getLinkage(); GlobalValue::VisibilityTypes Visibility = NamePtr->getVisibility(); @@ -759,15 +758,16 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) { // of the parent function, that will result in relocations against discarded // sections. Comdat *Cmdt = nullptr; - GlobalValue::LinkageTypes CounterLinkage = Linkage; if (needsComdatForCounter(*Fn, *M)) { StringRef CmdtPrefix = getInstrProfComdatPrefix(); if (TT.isOSBinFormatCOFF()) { // For COFF, the comdat group name must be the name of a symbol in the // group. Use the counter variable name, and upgrade its linkage to - // something externally visible, like linkonce_odr. + // something externally visible, like linkonce_odr. Use hidden visibility + // to imply that this is dso local. CmdtPrefix = getInstrProfCountersVarPrefix(); - CounterLinkage = GlobalValue::LinkOnceODRLinkage; + Linkage = GlobalValue::LinkOnceODRLinkage; + Visibility = GlobalValue::HiddenVisibility; } Cmdt = M->getOrInsertComdat(getVarName(Inc, CmdtPrefix)); } @@ -786,7 +786,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) { getInstrProfSectionName(IPSK_cnts, TT.getObjectFormat())); CounterPtr->setAlignment(8); CounterPtr->setComdat(Cmdt); - CounterPtr->setLinkage(CounterLinkage); + CounterPtr->setLinkage(Linkage); auto *Int8PtrTy = Type::getInt8PtrTy(Ctx); // Allocate statically the array of pointers to value profile nodes for @@ -841,6 +841,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) { Data->setSection(getInstrProfSectionName(IPSK_data, TT.getObjectFormat())); Data->setAlignment(INSTR_PROF_DATA_ALIGNMENT); Data->setComdat(Cmdt); + Data->setLinkage(Linkage); PD.RegionCounters = CounterPtr; PD.DataVar = Data; diff --git a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll index af95f9a..81be1dc 100644 --- a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll +++ b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll @@ -20,8 +20,8 @@ $_Z3barIvEvv = comdat any ; COFF-NOT: __profn__Z3barIvEvv -; COFF: @__profc__Z3barIvEvv = linkonce_odr dso_local global [1 x i64] zeroinitializer, section "{{.*}}prfc$M", comdat, align 8 -; COFF: @__profd__Z3barIvEvv = internal global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [2 x i16] zeroinitializer }, section "{{.*}}prfd{{.*}}", comdat($__profc__Z3barIvEvv), align 8 +; COFF: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}prfc$M", comdat, align 8 +; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [2 x i16] zeroinitializer }, section "{{.*}}prfd{{.*}}", comdat($__profc__Z3barIvEvv), align 8 declare void @llvm.instrprof.increment(i8*, i64, i32, i32) #1 diff --git a/llvm/test/Instrumentation/InstrProfiling/comdat.ll b/llvm/test/Instrumentation/InstrProfiling/comdat.ll index 03ee905..bea8e1d 100644 --- a/llvm/test/Instrumentation/InstrProfiling/comdat.ll +++ b/llvm/test/Instrumentation/InstrProfiling/comdat.ll @@ -17,8 +17,8 @@ $foo_inline = comdat any ; ELF: @__profc_foo_inline = linkonce_odr hidden global{{.*}}, section "__llvm_prf_cnts", comdat($__profv_foo_inline), align 8 ; ELF: @__profd_foo_inline = linkonce_odr hidden global{{.*}}, section "__llvm_prf_data", comdat($__profv_foo_inline), align 8 -; COFF: @__profc_foo_inline = linkonce_odr dso_local global{{.*}}, section ".lprfc$M", comdat, align 8 -; COFF: @__profd_foo_inline = internal global{{.*}}, section ".lprfd$M", comdat($__profc_foo_inline), align 8 +; COFF: @__profc_foo_inline = linkonce_odr hidden global{{.*}}, section ".lprfc$M", comdat, align 8 +; COFF: @__profd_foo_inline = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat($__profc_foo_inline), align 8 define weak_odr void @foo_inline() comdat { call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_inline, i32 0, i32 0), i64 0, i32 1, i32 0) ret void @@ -30,8 +30,8 @@ $foo_extern = comdat any ; ELF: @__profc_foo_extern = linkonce_odr hidden global{{.*}}, section "__llvm_prf_cnts", comdat($__profv_foo_extern) ; ELF: @__profd_foo_extern = linkonce_odr hidden global{{.*}}, section "__llvm_prf_data", comdat($__profv_foo_extern) -; COFF: @__profc_foo_extern = linkonce_odr dso_local global{{.*}}, section ".lprfc$M", comdat, align 8 -; COFF: @__profd_foo_extern = internal global{{.*}}, section ".lprfd$M", comdat($__profc_foo_extern), align 8 +; COFF: @__profc_foo_extern = linkonce_odr hidden global{{.*}}, section ".lprfc$M", comdat, align 8 +; COFF: @__profd_foo_extern = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat($__profc_foo_extern), align 8 define available_externally void @foo_extern() { call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_extern, i32 0, i32 0), i64 0, i32 1, i32 0) ret void diff --git a/llvm/test/Instrumentation/InstrProfiling/linkage.ll b/llvm/test/Instrumentation/InstrProfiling/linkage.ll index 29ae5d6..e086add 100644 --- a/llvm/test/Instrumentation/InstrProfiling/linkage.ll +++ b/llvm/test/Instrumentation/InstrProfiling/linkage.ll @@ -57,8 +57,8 @@ define linkonce_odr void @foo_inline() { ; LINUX: @__profd_foo_extern = linkonce_odr hidden global {{.*}}section "__llvm_prf_data", comdat($__profv_foo_extern), align 8 ; MACHO: @__profc_foo_extern = linkonce_odr hidden global ; MACHO: @__profd_foo_extern = linkonce_odr hidden global -; COFF: @__profc_foo_extern = linkonce_odr dso_local global {{.*}}section ".lprfc$M", comdat, align 8 -; COFF: @__profd_foo_extern = internal global {{.*}}section ".lprfd$M", comdat($__profc_foo_extern), align 8 +; COFF: @__profc_foo_extern = linkonce_odr hidden global {{.*}}section ".lprfc$M", comdat, align 8 +; COFF: @__profd_foo_extern = linkonce_odr hidden global {{.*}}section ".lprfd$M", comdat($__profc_foo_extern), align 8 define available_externally void @foo_extern() { call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_extern, i32 0, i32 0), i64 0, i32 1, i32 0) ret void