[llvm] [InstrProf][X86] Mark non-directly accessed globals as large (PR #74778)
Arthur Eubanks via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 7 15:01:31 PST 2023
https://github.com/aeubanks created https://github.com/llvm/llvm-project/pull/74778
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.
>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] [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 3035cdeeacf68a..0e97b7d8de3ad3 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 3a3b41f5dc87d1..b175e6f93f3e8f 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 10258e25467913..d3282779d9f5f3 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 806afc8fcdf7cb..199afbe966dde4 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 c90f37c8208957..502cef8a73a0e0 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"
More information about the llvm-commits
mailing list