[InstrProf][X86] Mark non-directly accessed globals as large (#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.

5 files changed, 46 insertions, 8 deletions

diff --git a/llvm/include/llvm/Transforms/Instrumentation.h b/llvm/include/llvm/Transforms/Instrumentation.h
index 3035cde..bb1a0d4 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 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
 struct GCOVOptions {
   static GCOVOptions getDefault();
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 3a3b41f5..b175e6f 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 10258e2..d328277 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 806afc8..199afbe 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 c90f37c..9fbff45 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-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"
 
@@ -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 +76,26 @@ 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
+
+; 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