[llvm] [NFCI][Globals]For GlobalObjects, add updateSectionPrefix and change setSectionPrefix to handle empty strings (PR #158460)
Mingming Liu via llvm-commits
llvm-commits at lists.llvm.org
Sat Sep 13 23:20:35 PDT 2025
https://github.com/mingmingl-llvm updated https://github.com/llvm/llvm-project/pull/158460
>From 887e2705800396e09ab7462817043b727291666f Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Sat, 13 Sep 2025 23:16:50 -0700
Subject: [PATCH 1/2] [NFCI][Globals]Add GlobalObjects::updateSectionPrefix and
change setSectionPrefix to handle empty strings
---
llvm/include/llvm/IR/GlobalObject.h | 7 ++-
llvm/lib/IR/Globals.cpp | 17 ++++++
llvm/unittests/IR/CMakeLists.txt | 1 +
llvm/unittests/IR/GlobalObjectTest.cpp | 81 ++++++++++++++++++++++++++
4 files changed, 105 insertions(+), 1 deletion(-)
create mode 100644 llvm/unittests/IR/GlobalObjectTest.cpp
diff --git a/llvm/include/llvm/IR/GlobalObject.h b/llvm/include/llvm/IR/GlobalObject.h
index 08a02b42bdc14..740d7fb9bc41f 100644
--- a/llvm/include/llvm/IR/GlobalObject.h
+++ b/llvm/include/llvm/IR/GlobalObject.h
@@ -121,9 +121,14 @@ class GlobalObject : public GlobalValue {
/// appropriate default object file section.
LLVM_ABI void setSection(StringRef S);
- /// Set the section prefix for this global object.
+ /// Set the section prefix for this global object. If \p Prefix is empty,
+ /// the section prefix metadata will be cleared if it exists.
LLVM_ABI void setSectionPrefix(StringRef Prefix);
+ /// If \p Prefix is different from existing prefix, update section prefix.
+ /// Returns true if an update happens and false otherwise.
+ LLVM_ABI bool updateSectionPrefix(StringRef Prefix);
+
/// Get the section prefix for this global object.
LLVM_ABI std::optional<StringRef> getSectionPrefix() const;
diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index 11d33e262fecb..0731fcbde106a 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -289,11 +289,28 @@ void GlobalObject::setSection(StringRef S) {
}
void GlobalObject::setSectionPrefix(StringRef Prefix) {
+ if (Prefix.empty()) {
+ setMetadata(LLVMContext::MD_section_prefix, nullptr);
+ return;
+ }
MDBuilder MDB(getContext());
setMetadata(LLVMContext::MD_section_prefix,
MDB.createGlobalObjectSectionPrefix(Prefix));
}
+bool GlobalObject::updateSectionPrefix(StringRef Prefix) {
+ auto MD = getMetadata(LLVMContext::MD_section_prefix);
+ StringRef ExistingPrefix; // Empty by default.
+ if (MD != nullptr)
+ ExistingPrefix = cast<MDString>(MD->getOperand(1))->getString();
+
+ if (ExistingPrefix != Prefix) {
+ setSectionPrefix(Prefix);
+ return true;
+ }
+ return false;
+}
+
std::optional<StringRef> GlobalObject::getSectionPrefix() const {
if (MDNode *MD = getMetadata(LLVMContext::MD_section_prefix)) {
[[maybe_unused]] StringRef MDName =
diff --git a/llvm/unittests/IR/CMakeLists.txt b/llvm/unittests/IR/CMakeLists.txt
index 8b7bd3997ea27..d62ce66ef9d34 100644
--- a/llvm/unittests/IR/CMakeLists.txt
+++ b/llvm/unittests/IR/CMakeLists.txt
@@ -28,6 +28,7 @@ add_llvm_unittest(IRTests
DominatorTreeBatchUpdatesTest.cpp
DroppedVariableStatsIRTest.cpp
FunctionTest.cpp
+ GlobalObjectTest.cpp
PassBuilderCallbacksTest.cpp
IRBuilderTest.cpp
InstructionsTest.cpp
diff --git a/llvm/unittests/IR/GlobalObjectTest.cpp b/llvm/unittests/IR/GlobalObjectTest.cpp
new file mode 100644
index 0000000000000..0732b6f6691f1
--- /dev/null
+++ b/llvm/unittests/IR/GlobalObjectTest.cpp
@@ -0,0 +1,81 @@
+//===- GlobalObjectTest.cpp - Global object unit tests --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/GlobalObject.h"
+#include "llvm-c/Core.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+#include "gmock/gmock.h"
+using namespace llvm;
+namespace {
+
+using testing::Eq;
+using testing::Optional;
+using testing::StrEq;
+
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+ SMDiagnostic Err;
+ std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
+ if (!Mod)
+ Err.print("GlobalObjectTests", errs());
+ return Mod;
+}
+
+static LLVMContext C;
+static std::unique_ptr<Module> M;
+
+class GlobalObjectTest : public testing::Test {
+public:
+static void SetUpTestSuite() {
+
+ M = parseIR(C, R"(
+ at foo = global i32 3, !section_prefix !0
+ at bar = global i32 0
+
+!0 = !{!"section_prefix", !"hot"}
+)");
+
+ }
+
+};
+
+TEST_F(GlobalObjectTest, SectionPrefix) {
+ GlobalVariable* Foo = M->getGlobalVariable("foo");
+
+ // Initial section prefix is hot.
+ ASSERT_NE(Foo, nullptr);
+ ASSERT_THAT(Foo->getSectionPrefix(), Optional(StrEq("hot")));
+
+ // No actual update.
+ EXPECT_FALSE(Foo->updateSectionPrefix("hot"));
+
+ // Update prefix from hot to unlikely.
+ Foo->setSectionPrefix("unlikely");
+ EXPECT_THAT(Foo->getSectionPrefix(), Optional(StrEq("unlikely")));
+
+ // Update prefix to empty is the same as clear.
+ Foo->setSectionPrefix("");
+ EXPECT_THAT(Foo->getSectionPrefix(), Eq(std::nullopt));
+
+ GlobalVariable* Bar = M->getGlobalVariable("bar");
+
+ // Initial section prefix is empty.
+ ASSERT_NE(Bar, nullptr);
+ ASSERT_THAT(Bar->getSectionPrefix(), Eq(std::nullopt));
+
+ // No actual update.
+ EXPECT_FALSE(Bar->updateSectionPrefix(""));
+
+ // Update from empty to hot.
+ EXPECT_TRUE(Bar->updateSectionPrefix("hot"));
+ EXPECT_THAT(Bar->getSectionPrefix(), Optional(StrEq("hot")));
+}
+
+} // namespace
>From 314696a7adc95e47f4937e6a218b081e29b1d709 Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Sat, 13 Sep 2025 23:19:47 -0700
Subject: [PATCH 2/2] run clang format
---
llvm/unittests/IR/GlobalObjectTest.cpp | 57 ++++++++++++--------------
1 file changed, 26 insertions(+), 31 deletions(-)
diff --git a/llvm/unittests/IR/GlobalObjectTest.cpp b/llvm/unittests/IR/GlobalObjectTest.cpp
index 0732b6f6691f1..26949ae3a39fa 100644
--- a/llvm/unittests/IR/GlobalObjectTest.cpp
+++ b/llvm/unittests/IR/GlobalObjectTest.cpp
@@ -11,11 +11,10 @@
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/SourceMgr.h"
-#include "gtest/gtest.h"
#include "gmock/gmock.h"
+#include "gtest/gtest.h"
using namespace llvm;
namespace {
-
using testing::Eq;
using testing::Optional;
using testing::StrEq;
@@ -33,49 +32,45 @@ static std::unique_ptr<Module> M;
class GlobalObjectTest : public testing::Test {
public:
-static void SetUpTestSuite() {
-
+ static void SetUpTestSuite() {
M = parseIR(C, R"(
@foo = global i32 3, !section_prefix !0
@bar = global i32 0
!0 = !{!"section_prefix", !"hot"}
)");
-
}
-
};
TEST_F(GlobalObjectTest, SectionPrefix) {
- GlobalVariable* Foo = M->getGlobalVariable("foo");
-
- // Initial section prefix is hot.
- ASSERT_NE(Foo, nullptr);
- ASSERT_THAT(Foo->getSectionPrefix(), Optional(StrEq("hot")));
+ GlobalVariable *Foo = M->getGlobalVariable("foo");
- // No actual update.
- EXPECT_FALSE(Foo->updateSectionPrefix("hot"));
+ // Initial section prefix is hot.
+ ASSERT_NE(Foo, nullptr);
+ ASSERT_THAT(Foo->getSectionPrefix(), Optional(StrEq("hot")));
- // Update prefix from hot to unlikely.
- Foo->setSectionPrefix("unlikely");
- EXPECT_THAT(Foo->getSectionPrefix(), Optional(StrEq("unlikely")));
-
- // Update prefix to empty is the same as clear.
- Foo->setSectionPrefix("");
- EXPECT_THAT(Foo->getSectionPrefix(), Eq(std::nullopt));
+ // No actual update.
+ EXPECT_FALSE(Foo->updateSectionPrefix("hot"));
- GlobalVariable* Bar = M->getGlobalVariable("bar");
+ // Update prefix from hot to unlikely.
+ Foo->setSectionPrefix("unlikely");
+ EXPECT_THAT(Foo->getSectionPrefix(), Optional(StrEq("unlikely")));
- // Initial section prefix is empty.
- ASSERT_NE(Bar, nullptr);
- ASSERT_THAT(Bar->getSectionPrefix(), Eq(std::nullopt));
-
- // No actual update.
- EXPECT_FALSE(Bar->updateSectionPrefix(""));
+ // Update prefix to empty is the same as clear.
+ Foo->setSectionPrefix("");
+ EXPECT_THAT(Foo->getSectionPrefix(), Eq(std::nullopt));
- // Update from empty to hot.
- EXPECT_TRUE(Bar->updateSectionPrefix("hot"));
- EXPECT_THAT(Bar->getSectionPrefix(), Optional(StrEq("hot")));
-}
+ GlobalVariable *Bar = M->getGlobalVariable("bar");
+
+ // Initial section prefix is empty.
+ ASSERT_NE(Bar, nullptr);
+ ASSERT_THAT(Bar->getSectionPrefix(), Eq(std::nullopt));
+ // No actual update.
+ EXPECT_FALSE(Bar->updateSectionPrefix(""));
+
+ // Update from empty to hot.
+ EXPECT_TRUE(Bar->updateSectionPrefix("hot"));
+ EXPECT_THAT(Bar->getSectionPrefix(), Optional(StrEq("hot")));
+}
} // namespace
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