Merging r372020 and r372182:
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r372020 | rnk | 2019-09-16 11:49:09 -0700 (Mon, 16 Sep 2019) | 30 lines
[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
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r372182 | rnk | 2019-09-17 14:10:49 -0700 (Tue, 17 Sep 2019) | 12 lines
[PGO] Don't use comdat groups for counters & data on COFF
For COFF, a comdat group is really a symbol marked
IMAGE_COMDAT_SELECT_ANY and zero or more other symbols marked
IMAGE_COMDAT_SELECT_ASSOCIATIVE. Typically the associative symbols in
the group are not external and are not referenced by other TUs, they are
things like debug info, C++ dynamic initializers, or other section
registration schemes. The Visual C++ linker reports a duplicate symbol
error for symbols marked IMAGE_COMDAT_SELECT_ASSOCIATIVE even if they
would be discarded after handling the leader symbol.
Fixes coverage-inline.cpp in check-profile after r372020.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_90@374858 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Instrumentation/InstrProfiling.cpp b/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 63c2b80..5d3a793 100644
--- a/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -731,9 +731,8 @@
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();
@@ -749,19 +748,25 @@
// new comdat group for the counters and profiling data. If we use the comdat
// 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();
+ bool NeedComdat = needsComdatForCounter(*Fn, *M);
+ Comdat *Cmdt = nullptr; // Comdat group.
+ if (NeedComdat) {
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.
- CmdtPrefix = getInstrProfCountersVarPrefix();
- CounterLinkage = GlobalValue::LinkOnceODRLinkage;
+ // For COFF, put the counters, data, and values each into their own
+ // comdats. We can't use a group because the Visual C++ linker will
+ // report duplicate symbol errors if there are multiple external symbols
+ // with the same name marked IMAGE_COMDAT_SELECT_ASSOCIATIVE.
+ Linkage = GlobalValue::LinkOnceODRLinkage;
+ Visibility = GlobalValue::HiddenVisibility;
+ } else {
+ // Otherwise, create one comdat group for everything.
+ Cmdt = M->getOrInsertComdat(getVarName(Inc, getInstrProfComdatPrefix()));
}
- Cmdt = M->getOrInsertComdat(getVarName(Inc, CmdtPrefix));
}
+ auto MaybeSetComdat = [=](GlobalVariable *GV) {
+ if (NeedComdat)
+ GV->setComdat(Cmdt ? Cmdt : M->getOrInsertComdat(GV->getName()));
+ };
uint64_t NumCounters = Inc->getNumCounters()->getZExtValue();
LLVMContext &Ctx = M->getContext();
@@ -776,8 +781,8 @@
CounterPtr->setSection(
getInstrProfSectionName(IPSK_cnts, TT.getObjectFormat()));
CounterPtr->setAlignment(8);
- CounterPtr->setComdat(Cmdt);
- CounterPtr->setLinkage(CounterLinkage);
+ MaybeSetComdat(CounterPtr);
+ CounterPtr->setLinkage(Linkage);
auto *Int8PtrTy = Type::getInt8PtrTy(Ctx);
// Allocate statically the array of pointers to value profile nodes for
@@ -798,7 +803,7 @@
ValuesVar->setSection(
getInstrProfSectionName(IPSK_vals, TT.getObjectFormat()));
ValuesVar->setAlignment(8);
- ValuesVar->setComdat(Cmdt);
+ MaybeSetComdat(ValuesVar);
ValuesPtrExpr =
ConstantExpr::getBitCast(ValuesVar, Type::getInt8PtrTy(Ctx));
}
@@ -831,7 +836,8 @@
Data->setVisibility(Visibility);
Data->setSection(getInstrProfSectionName(IPSK_data, TT.getObjectFormat()));
Data->setAlignment(INSTR_PROF_DATA_ALIGNMENT);
- Data->setComdat(Cmdt);
+ MaybeSetComdat(Data);
+ Data->setLinkage(Linkage);
PD.RegionCounters = CounterPtr;
PD.DataVar = Data;
diff --git a/test/Instrumentation/InstrProfiling/PR23499.ll b/test/Instrumentation/InstrProfiling/PR23499.ll
index af95f9a..a5e20b1 100644
--- a/test/Instrumentation/InstrProfiling/PR23499.ll
+++ b/test/Instrumentation/InstrProfiling/PR23499.ll
@@ -20,8 +20,8 @@
; 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$M", comdat, align 8
+; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [2 x i16] zeroinitializer }, section "{{.*}}prfd{{.*}}", comdat, align 8
declare void @llvm.instrprof.increment(i8*, i64, i32, i32) #1
diff --git a/test/Instrumentation/InstrProfiling/comdat.ll b/test/Instrumentation/InstrProfiling/comdat.ll
index 03ee905..5ff820c 100644
--- a/test/Instrumentation/InstrProfiling/comdat.ll
+++ b/test/Instrumentation/InstrProfiling/comdat.ll
@@ -17,8 +17,8 @@
; ELF: @__profc_foo_inline = linkonce_odr hidden global{{.*}}, section "__llvm_prf_cnts", comdat($__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, 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 @@
; 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$M", comdat, align 8
define available_externally void @foo_extern() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_extern, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
diff --git a/test/Instrumentation/InstrProfiling/linkage.ll b/test/Instrumentation/InstrProfiling/linkage.ll
index 29ae5d6..13e389b 100644
--- a/test/Instrumentation/InstrProfiling/linkage.ll
+++ b/test/Instrumentation/InstrProfiling/linkage.ll
@@ -57,8 +57,8 @@
; LINUX: @__profd_foo_extern = linkonce_odr hidden global {{.*}}section "__llvm_prf_data", comdat($__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, 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
