[profiling] Remove dead profile name vars after emitting name data

The profile name variables passed to counter increment intrinsics are
dead after we emit the finalized name data in __llvm_prf_nm. However, we
neglect to erase these name variables. This causes huge size increases
in the __TEXT,__const section as well as slowdowns when linker dead
stripping is disabled. Some affected projects are so massive that they
fail to link on Darwin, because only the small code model is supported.

Fix the issue by throwing away the name constants as soon as we're done
with them.

Differential Revision: https://reviews.llvm.org/D29921

llvm-svn: 295084

5 files changed, 11 insertions, 8 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index be5c2c711f0..87387ac3a1b 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -532,6 +532,9 @@ void InstrProfiling::emitNameData() {
   NamesSize = CompressedNameStr.size();
   NamesVar->setSection(getNameSection());
   UsedVars.push_back(NamesVar);
+
+  for (auto *NamePtr : ReferencedNames)
+    NamePtr->eraseFromParent();
 }
 
 void InstrProfiling::emitRegistration() {
diff --git a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
index 47c60fd802a..2aac04e512f 100644
--- a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
@@ -13,13 +13,13 @@ $_Z3barIvEvv = comdat any
 
 @__profn__Z3barIvEvv = linkonce_odr hidden constant [11 x i8] c"_Z3barIvEvv", align 1
 
-; CHECK: @__profn__Z3barIvEvv = private constant [11 x i8] c"_Z3barIvEvv", align 1
+; CHECK-NOT: __profn__Z3barIvEvv
 ; CHECK: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}__llvm_prf_cnts", comdat($__profv__Z3barIvEvv), align 8
 ; CHECK: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [1 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [1 x i16] zeroinitializer }, section "{{.*}}__llvm_prf_data{{.*}}", comdat($__profv__Z3barIvEvv), align 8
 ; CHECK: @__llvm_prf_nm = private constant [{{.*}} x i8] c"{{.*}}", section "{{.*}}__llvm_prf_names"
 
 
-; COFF: @__profn__Z3barIvEvv = private constant [11 x i8] c"_Z3barIvEvv", align 1
+; COFF-NOT: __profn__Z3barIvEvv
 ; COFF: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}__llvm_prf_cnts", comdat, align 8
 ; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [1 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, [1 x i16] zeroinitializer }, section "{{.*}}__llvm_prf_data{{.*}}", comdat($__profc__Z3barIvEvv), align 8
 
diff --git a/llvm/test/Instrumentation/InstrProfiling/platform.ll b/llvm/test/Instrumentation/InstrProfiling/platform.ll
index b731fc3e5ff..c0c711054ff 100644
--- a/llvm/test/Instrumentation/InstrProfiling/platform.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/platform.ll
@@ -12,8 +12,8 @@
 ; RUN: opt < %s -mtriple=x86_64-pc-solaris -passes=instrprof -S | FileCheck %s -check-prefix=SOLARIS
 
 @__profn_foo = hidden constant [3 x i8] c"foo"
-; MACHO: @__profn_foo = private constant [3 x i8] c"foo"
-; ELF: @__profn_foo = private constant [3 x i8] c"foo"
+; MACHO-NOT: __profn_foo
+; ELF-NOT: __profn_foo
 
 ; MACHO: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
 ; ELF: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", align 8
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 508d3ef8dea..c4cc1d9ce43 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -4,11 +4,11 @@
 target triple = "x86_64-apple-macosx10.10.0"
 
 @__profn_foo = hidden constant [3 x i8] c"foo"
-; CHECK: @__profn_foo = private constant [3 x i8] c"foo"
+; CHECK-NOT: __profn_foo
 @__profn_bar = hidden constant [4 x i8] c"bar\00"
-; CHECK: @__profn_bar = private constant [4 x i8] c"bar\00"
+; CHECK-NOT: __profn_bar
 @__profn_baz = hidden constant [3 x i8] c"baz"
-; CHECK: @__profn_baz = private constant [3 x i8] c"baz"
+; CHECK-NOT: __profn_baz
 
 ; CHECK: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
 ; CHECK: @__profd_foo = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
diff --git a/llvm/test/Transforms/PGOProfile/comdat_internal.ll b/llvm/test/Transforms/PGOProfile/comdat_internal.ll
index 7df6f91fe72..36affd5392f 100644
--- a/llvm/test/Transforms/PGOProfile/comdat_internal.ll
+++ b/llvm/test/Transforms/PGOProfile/comdat_internal.ll
@@ -12,7 +12,7 @@ $foo = comdat any
 @bar = global i32 ()* @foo, align 8
 
 ; CHECK: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
-; CHECK: @__profn__stdin__foo = private constant [11 x i8] c"<stdin>:foo"
+; CHECK-NOT: __profn__stdin__foo
 ; CHECK: @__profc__stdin__foo.[[FOO_HASH]] = private global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat($__profv__stdin__foo.[[FOO_HASH]]), align 8
 ; CHECK: @__profd__stdin__foo.[[FOO_HASH]] = private global { i64, i64, i64*, i8*, i8*, i32, [1 x i16] } { i64 -5640069336071256030, i64 [[FOO_HASH]], i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__stdin__foo.[[FOO_HASH]], i32 0, i32 0), i8* null
 ; CHECK-NOT: bitcast (i32 ()* @foo to i8*)