[llvm] [NFCI] Avoid adding duplicated SpecialCaseList::Sections. (PR #140478)

[Qinkun Bao via llvm-commits]

https://github.com/qinkunbao updated https://github.com/llvm/llvm-project/pull/140478

>From c51ac31bd7ec778fcbb9faf74d9645384cf67206 Mon Sep 17 00:00:00 2001
From: Qinkun Bao <qinkun at google.com>
Date: Sun, 18 May 2025 20:51:54 +0000
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.6
---
 llvm/lib/Support/SpecialCaseList.cpp          | 18 +++++++++++------
 .../unittests/Support/SpecialCaseListTest.cpp | 20 +++++++++++++++++++
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Support/SpecialCaseList.cpp b/llvm/lib/Support/SpecialCaseList.cpp
index dddf84cbb1ced..926aadb65d493 100644
--- a/llvm/lib/Support/SpecialCaseList.cpp
+++ b/llvm/lib/Support/SpecialCaseList.cpp
@@ -132,18 +132,24 @@ bool SpecialCaseList::createInternal(const MemoryBuffer *MB,
 Expected<SpecialCaseList::Section *>
 SpecialCaseList::addSection(StringRef SectionStr, unsigned LineNo,
                             bool UseGlobs) {
-  Sections.emplace_back();
-  auto &Section = Sections.back();
-  Section.SectionStr = SectionStr;
-
-  if (auto Err = Section.SectionMatcher->insert(SectionStr, LineNo, UseGlobs)) {
+  auto it =
+      std::find_if(Sections.begin(), Sections.end(), [&](const Section &s) {
+        return s.SectionStr == SectionStr;
+      });
+  if (it == Sections.end()) {
+    Sections.emplace_back();
+    auto &sec = Sections.back();
+    sec.SectionStr = SectionStr;
+  }
+  it = std::prev(Sections.end());
+  if (auto Err = it->SectionMatcher->insert(SectionStr, LineNo, UseGlobs)) {
     return createStringError(errc::invalid_argument,
                              "malformed section at line " + Twine(LineNo) +
                                  ": '" + SectionStr +
                                  "': " + toString(std::move(Err)));
   }
 
-  return &Section;
+  return &(*it);
 }
 
 bool SpecialCaseList::parse(const MemoryBuffer *MB, std::string &Error) {
diff --git a/llvm/unittests/Support/SpecialCaseListTest.cpp b/llvm/unittests/Support/SpecialCaseListTest.cpp
index 4289a5e702155..15dc0222a57c3 100644
--- a/llvm/unittests/Support/SpecialCaseListTest.cpp
+++ b/llvm/unittests/Support/SpecialCaseListTest.cpp
@@ -306,4 +306,24 @@ TEST_F(SpecialCaseListTest, Version2) {
   EXPECT_TRUE(SCL->inSection("sect2", "fun", "bar"));
   EXPECT_FALSE(SCL->inSection("sect3", "fun", "bar"));
 }
+
+TEST_F(SpecialCaseListTest, Version3) {
+  std::unique_ptr<SpecialCaseList> SCL = makeSpecialCaseList("[sect1]\n"
+                                                             "fun:foo*\n"
+                                                             "[sect1]\n"
+                                                             "fun:bar*\n"
+                                                             "[sect2]\n"
+                                                             "fun:def\n");
+  EXPECT_TRUE(SCL->inSection("sect1", "fun", "fooz"));
+  EXPECT_TRUE(SCL->inSection("sect1", "fun", "barz"));
+  EXPECT_FALSE(SCL->inSection("sect2", "fun", "fooz"));
+
+  EXPECT_TRUE(SCL->inSection("sect2", "fun", "def"));
+  EXPECT_FALSE(SCL->inSection("sect1", "fun", "def"));
+
+  EXPECT_EQ(2u, SCL->inSectionBlame("sect1", "fun", "fooz"));
+  EXPECT_EQ(4u, SCL->inSectionBlame("sect1", "fun", "barz"));
+  EXPECT_EQ(6u, SCL->inSectionBlame("sect2", "fun", "def"));
+}
+
 }