[llvm] [InstrProf][X86] Mark non-directly accessed globals as large (PR #74778)
Arthur Eubanks via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 8 09:31:43 PST 2023
https://github.com/aeubanks updated https://github.com/llvm/llvm-project/pull/74778
>From 6e8fc9669c8f73ce1092b1f39fe6e81b9e50cf41 Mon Sep 17 00:00:00 2001
From: Arthur Eubanks <aeubanks at google.com>
Date: Tue, 5 Dec 2023 12:42:29 -0800
Subject: [PATCH 1/2] [InstrProf][X86] Mark non-directly accessed globals as
large
We'd like to make various instrprof globals large to make them not
contribute to relocation pressure since there are no direct accesses
to them in the module.
Similar to what was done for asan_globals in #74514.
This affects the __llvm_prf_vals, __llvm_prf_vnds, and __llvm_prf_names
sections.
---
.../include/llvm/Transforms/Instrumentation.h | 5 ++++
.../Instrumentation/AddressSanitizer.cpp | 4 +---
.../Instrumentation/InstrProfiling.cpp | 4 ++++
.../Instrumentation/Instrumentation.cpp | 7 ++++++
.../InstrProfiling/icall-comdat.ll | 23 +++++++++++++++----
5 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Instrumentation.h b/llvm/include/llvm/Transforms/Instrumentation.h
index 3035cdeeacf68..0e97b7d8de3ad 100644
--- a/llvm/include/llvm/Transforms/Instrumentation.h
+++ b/llvm/include/llvm/Transforms/Instrumentation.h
@@ -49,6 +49,11 @@ GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
// Returns nullptr on failure.
Comdat *getOrCreateFunctionComdat(Function &F, Triple &T);
+// Place global in a large section for x86-64 ELF binaries to mitigate
+// relocation pressure. Should typically be used for metadata globals that
+// aren't directly accessed in the module.
+void setGlobalVariableLargeSection(Triple &TargetTriple, GlobalVariable &GV);
+
// Insert GCOV profiling instrumentation
struct GCOVOptions {
static GCOVOptions getDefault();
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 3a3b41f5dc87d..b175e6f93f3e8 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2146,9 +2146,7 @@ ModuleAddressSanitizer::CreateMetadataGlobal(Module &M, Constant *Initializer,
Metadata->setSection(getGlobalMetadataSection());
// Place metadata in a large section for x86-64 ELF binaries to mitigate
// relocation pressure.
- if (TargetTriple.getArch() == Triple::x86_64 &&
- TargetTriple.getObjectFormat() == Triple::ELF)
- Metadata->setCodeModel(CodeModel::Large);
+ setGlobalVariableLargeSection(TargetTriple, *Metadata);
return Metadata;
}
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 10258e2546791..d3282779d9f5f 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -49,6 +49,7 @@
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/TargetParser/Triple.h"
+#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Instrumentation/PGOInstrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
@@ -1294,6 +1295,7 @@ void InstrProfiling::createDataVariable(InstrProfCntrInstBase *Inc) {
*M, ValuesTy, false, Linkage, Constant::getNullValue(ValuesTy),
getVarName(Inc, getInstrProfValuesVarPrefix(), Renamed));
ValuesVar->setVisibility(Visibility);
+ setGlobalVariableLargeSection(TT, *ValuesVar);
ValuesVar->setSection(
getInstrProfSectionName(IPSK_vals, TT.getObjectFormat()));
ValuesVar->setAlignment(Align(8));
@@ -1422,6 +1424,7 @@ void InstrProfiling::emitVNodes() {
auto *VNodesVar = new GlobalVariable(
*M, VNodesTy, false, GlobalValue::PrivateLinkage,
Constant::getNullValue(VNodesTy), getInstrProfVNodesVarName());
+ setGlobalVariableLargeSection(TT, *VNodesVar);
VNodesVar->setSection(
getInstrProfSectionName(IPSK_vnodes, TT.getObjectFormat()));
VNodesVar->setAlignment(M->getDataLayout().getABITypeAlign(VNodesTy));
@@ -1449,6 +1452,7 @@ void InstrProfiling::emitNameData() {
GlobalValue::PrivateLinkage, NamesVal,
getInstrProfNamesVarName());
NamesSize = CompressedNameStr.size();
+ setGlobalVariableLargeSection(TT, *NamesVar);
NamesVar->setSection(
getInstrProfSectionName(IPSK_name, TT.getObjectFormat()));
// On COFF, it's important to reduce the alignment down to 1 to prevent the
diff --git a/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp b/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
index 806afc8fcdf7c..199afbe966dde 100644
--- a/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/Instrumentation.cpp
@@ -85,3 +85,10 @@ Comdat *llvm::getOrCreateFunctionComdat(Function &F, Triple &T) {
return C;
}
+void llvm::setGlobalVariableLargeSection(Triple &TargetTriple,
+ GlobalVariable &GV) {
+ if (TargetTriple.getArch() == Triple::x86_64 &&
+ TargetTriple.getObjectFormat() == Triple::ELF) {
+ GV.setCodeModel(CodeModel::Large);
+ }
+}
diff --git a/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll b/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
index c90f37c820895..502cef8a73a0e 100644
--- a/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
@@ -1,5 +1,4 @@
;; Check that static counters are allocated for value profiler
-
; RUN: opt < %s -mtriple=x86_64-unknown-linux -passes=instrprof -vp-static-alloc=true -S | FileCheck %s --check-prefix=STATIC
; RUN: opt < %s -mtriple=powerpc-unknown-linux -passes=instrprof -vp-static-alloc=true -S | FileCheck %s --check-prefix=STATIC
; RUN: opt < %s -mtriple=sparc-unknown-linux -passes=instrprof -vp-static-alloc=true -S | FileCheck %s --check-prefix=STATIC
@@ -16,6 +15,10 @@
; RUN: opt %s -mtriple=powerpc64-ibm-aix -passes=instrprof -S | FileCheck %s --check-prefix=ALIGN
; RUN: opt %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=ALIGN
+;; Check that globals have the proper code model.
+; RUN: opt %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=X8664-CODEMODEL
+; RUN: opt %s -mtriple=powerpc-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=PPC-CODEMODEL
+
@__profn_foo = private constant [3 x i8] c"foo"
@__profn_bar = private constant [3 x i8] c"bar"
@@ -46,8 +49,8 @@ declare void @llvm.instrprof.value.profile(ptr, i64, i64, i32, i32) #0
attributes #0 = { nounwind }
-; STATIC: @__profvp_foo = private global [1 x i64] zeroinitializer, section "{{[^"]+}}", comdat($__profc_foo)
-; STATIC: @__profvp_bar = private global [1 x i64] zeroinitializer, section "{{[^"]+}}", comdat($__profc_bar)
+; STATIC: @__profvp_foo = private global [1 x i64] zeroinitializer, section "{{[^"]+}}",{{.*}} comdat($__profc_foo)
+; STATIC: @__profvp_bar = private global [1 x i64] zeroinitializer, section "{{[^"]+}}",{{.*}} comdat($__profc_bar)
; STATIC: @__llvm_prf_vnodes
; DYN-NOT: @__profvp_foo
@@ -73,5 +76,15 @@ attributes #0 = { nounwind }
; ALIGN: @__profc_bar = private global {{.*}} section "__llvm_prf_cnts",{{.*}} align 8
; ALIGN: @__profvp_bar = private global {{.*}} section "__llvm_prf_vals",{{.*}} align 8
; ALIGN: @__profd_bar = private global {{.*}} section "__llvm_prf_data",{{.*}} align 8
-; ALIGN: @__llvm_prf_vnodes = private global {{.*}} section "__llvm_prf_vnds", align 8
-; ALIGN: @__llvm_prf_nm = private constant {{.*}} section "__llvm_prf_names", align 1
+; ALIGN: @__llvm_prf_vnodes = private global {{.*}} section "__llvm_prf_vnds",{{.*}} align 8
+; ALIGN: @__llvm_prf_nm = private constant {{.*}} section "__llvm_prf_names",{{.*}} align 1
+
+; X8664-CODEMODEL-NOT: @__profc_foo = {{.*}}, code_model "large"
+; X8664-CODEMODEL: @__profvp_foo = {{.*}}, code_model "large"
+; X8664-CODEMODEL-NOT: @__profd_foo = {{.*}}, code_model "large"
+; X8664-CODEMODEL-NOT: @__profc_bar = {{.*}}, code_model "large"
+; X8664-CODEMODEL: @__profvp_bar = {{.*}}, code_model "large"
+; X8664-CODEMODEL-NOT: @__profd_bar = {{.*}}, code_model "large"
+; X8664-CODEMODEL: @__llvm_prf_vnodes = {{.*}}, code_model "large"
+; X8664-CODEMODEL: @__llvm_prf_nm = {{.*}}, code_model "large"
+; PPC-CODEMODEL-NOT: code_model "large"
>From 3a768b5608a7cd58b792c092ce99f146634974c4 Mon Sep 17 00:00:00 2001
From: Arthur Eubanks <aeubanks at google.com>
Date: Fri, 8 Dec 2023 09:31:27 -0800
Subject: [PATCH 2/2] address comments
---
.../include/llvm/Transforms/Instrumentation.h | 4 +--
.../InstrProfiling/icall-comdat.ll | 33 ++++++++++++-------
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Instrumentation.h b/llvm/include/llvm/Transforms/Instrumentation.h
index 0e97b7d8de3ad..bb1a0d446aa2a 100644
--- a/llvm/include/llvm/Transforms/Instrumentation.h
+++ b/llvm/include/llvm/Transforms/Instrumentation.h
@@ -50,8 +50,8 @@ GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
Comdat *getOrCreateFunctionComdat(Function &F, Triple &T);
// Place global in a large section for x86-64 ELF binaries to mitigate
-// relocation pressure. Should typically be used for metadata globals that
-// aren't directly accessed in the module.
+// relocation overflow pressure. This can be be used for metadata globals that
+// aren't directly accessed by code, which has no performance impact.
void setGlobalVariableLargeSection(Triple &TargetTriple, GlobalVariable &GV);
// Insert GCOV profiling instrumentation
diff --git a/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll b/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
index 502cef8a73a0e..9fbff456ff50b 100644
--- a/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/icall-comdat.ll
@@ -16,8 +16,8 @@
; RUN: opt %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=ALIGN
;; Check that globals have the proper code model.
-; RUN: opt %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=X8664-CODEMODEL
-; RUN: opt %s -mtriple=powerpc-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefix=PPC-CODEMODEL
+; RUN: opt %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefixes=CODEMODEL,CODEMODEL-X8664
+; RUN: opt %s -mtriple=powerpc-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefixes=CODEMODEL,CODEMODEL-PPC
@__profn_foo = private constant [3 x i8] c"foo"
@__profn_bar = private constant [3 x i8] c"bar"
@@ -79,12 +79,23 @@ attributes #0 = { nounwind }
; ALIGN: @__llvm_prf_vnodes = private global {{.*}} section "__llvm_prf_vnds",{{.*}} align 8
; ALIGN: @__llvm_prf_nm = private constant {{.*}} section "__llvm_prf_names",{{.*}} align 1
-; X8664-CODEMODEL-NOT: @__profc_foo = {{.*}}, code_model "large"
-; X8664-CODEMODEL: @__profvp_foo = {{.*}}, code_model "large"
-; X8664-CODEMODEL-NOT: @__profd_foo = {{.*}}, code_model "large"
-; X8664-CODEMODEL-NOT: @__profc_bar = {{.*}}, code_model "large"
-; X8664-CODEMODEL: @__profvp_bar = {{.*}}, code_model "large"
-; X8664-CODEMODEL-NOT: @__profd_bar = {{.*}}, code_model "large"
-; X8664-CODEMODEL: @__llvm_prf_vnodes = {{.*}}, code_model "large"
-; X8664-CODEMODEL: @__llvm_prf_nm = {{.*}}, code_model "large"
-; PPC-CODEMODEL-NOT: code_model "large"
+; CODEMODEL: @__profc_foo =
+; CODEMODEL-NOT: code_model "large"
+; CODEMODEL: @__profvp_foo =
+; CODEMODEL-X8664-SAME: code_model "large"
+; CODEMODEL-PPC-NOT: code_model
+; CODEMODEL: @__profd_foo =
+; CODEMODEL-NOT: code_model "large"
+; CODEMODEL: @__profc_bar =
+; CODEMODEL-NOT: code_model "large"
+; CODEMODEL: @__profvp_bar =
+; CODEMODEL-X8664-SAME: code_model "large"
+; CODEMODEL-PPC-NOT: code_model
+; CODEMODEL: @__profd_bar =
+; CODEMODEL-NOT: code_model "large"
+; CODEMODEL: @__llvm_prf_vnodes =
+; CODEMODEL-X8664-SAME: code_model "large"
+; CODEMODEL-PPC-NOT: code_model
+; CODEMODEL: @__llvm_prf_nm =
+; CODEMODEL-X8664-SAME: code_model "large"
+; CODEMODEL-PPC-NOT: code_model
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