[clang] Implement src:*=sanitize for UBSan (PR #140529)

[Qinkun Bao via cfe-commits]

https://github.com/qinkunbao created https://github.com/llvm/llvm-project/pull/140529

None

>From b83755d2aa0c5417ab8f359aa842449213437a7a Mon Sep 17 00:00:00 2001
From: Qinkun Bao <qinkun at google.com>
Date: Mon, 19 May 2025 11:14:01 +0000
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
 =?UTF-8?q?l=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.6
---
 .../clang/Basic/SanitizerSpecialCaseList.h    |  7 +++-
 clang/lib/Basic/NoSanitizeList.cpp            |  7 ++++
 clang/lib/Basic/SanitizerSpecialCaseList.cpp  | 16 ++++++++
 .../ubsan-src-ignorelist-category.test        | 37 +++++++++++++++++++
 4 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/CodeGen/ubsan-src-ignorelist-category.test

diff --git a/clang/include/clang/Basic/SanitizerSpecialCaseList.h b/clang/include/clang/Basic/SanitizerSpecialCaseList.h
index d024b7dfc2e85..25d518e7128cf 100644
--- a/clang/include/clang/Basic/SanitizerSpecialCaseList.h
+++ b/clang/include/clang/Basic/SanitizerSpecialCaseList.h
@@ -43,13 +43,18 @@ class SanitizerSpecialCaseList : public llvm::SpecialCaseList {
   bool inSection(SanitizerMask Mask, StringRef Prefix, StringRef Query,
                  StringRef Category = StringRef()) const;
 
+  // Query ignorelisted entries if any bit in Mask matches the entry's section.
+  // Return 0 if not found. If found, return the line number (starts with 1).
+  unsigned inSectionBlame(SanitizerMask Mask, StringRef Prefix, StringRef Query,
+                          StringRef Category = StringRef()) const;
+
 protected:
   // Initialize SanitizerSections.
   void createSanitizerSections();
 
   struct SanitizerSection {
     SanitizerSection(SanitizerMask SM, SectionEntries &E)
-        : Mask(SM), Entries(E){};
+        : Mask(SM), Entries(E) {};
 
     SanitizerMask Mask;
     SectionEntries &Entries;
diff --git a/clang/lib/Basic/NoSanitizeList.cpp b/clang/lib/Basic/NoSanitizeList.cpp
index e7e63c1f419e6..811480f914ec5 100644
--- a/clang/lib/Basic/NoSanitizeList.cpp
+++ b/clang/lib/Basic/NoSanitizeList.cpp
@@ -44,6 +44,13 @@ bool NoSanitizeList::containsFunction(SanitizerMask Mask,
 
 bool NoSanitizeList::containsFile(SanitizerMask Mask, StringRef FileName,
                                   StringRef Category) const {
+  unsigned nosanline = SSCL->inSectionBlame(Mask, "src", FileName, Category);
+  unsigned sanline = SSCL->inSectionBlame(Mask, "src", FileName, "sanitize");
+  // If we have two cases such as `src:a.cpp=sanitize` and `src:a.cpp`, the
+  // current entry override the previous entry.
+  if (nosanline > 0 && sanline > 0) {
+    return nosanline > sanline;
+  }
   return SSCL->inSection(Mask, "src", FileName, Category);
 }
 
diff --git a/clang/lib/Basic/SanitizerSpecialCaseList.cpp b/clang/lib/Basic/SanitizerSpecialCaseList.cpp
index 2dbf04c6ede97..7da36f3801453 100644
--- a/clang/lib/Basic/SanitizerSpecialCaseList.cpp
+++ b/clang/lib/Basic/SanitizerSpecialCaseList.cpp
@@ -63,3 +63,19 @@ bool SanitizerSpecialCaseList::inSection(SanitizerMask Mask, StringRef Prefix,
 
   return false;
 }
+
+unsigned SanitizerSpecialCaseList::inSectionBlame(SanitizerMask Mask,
+                                                  StringRef Prefix,
+                                                  StringRef Query,
+                                                  StringRef Category) const {
+  for (auto &S : SanitizerSections) {
+    if (S.Mask & Mask) {
+      unsigned lineNum =
+          SpecialCaseList::inSectionBlame(S.Entries, Prefix, Query, Category);
+      if (lineNum > 0) {
+        return lineNum;
+      }
+    }
+  }
+  return 0;
+}
diff --git a/clang/test/CodeGen/ubsan-src-ignorelist-category.test b/clang/test/CodeGen/ubsan-src-ignorelist-category.test
new file mode 100644
index 0000000000000..e0efd65df8652
--- /dev/null
+++ b/clang/test/CodeGen/ubsan-src-ignorelist-category.test
@@ -0,0 +1,37 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsanitize=signed-integer-overflow -fsanitize-ignorelist=%t/src.ignorelist -emit-llvm %t/test1.c -o - | FileCheck %s -check-prefix=CHECK-ALLOWLIST
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsanitize=signed-integer-overflow -fsanitize-ignorelist=%t/src.ignorelist -emit-llvm %t/test2.c -o - | FileCheck %s -check-prefix=CHECK-IGNORELIST
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsanitize=signed-integer-overflow -fsanitize-ignorelist=%t/src.ignorelist.contradict1 -emit-llvm %t/test1.c -o - | FileCheck %s -check-prefix=CHECK-ALLOWLISTOVERIDE1
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsanitize=signed-integer-overflow -fsanitize-ignorelist=%t/src.ignorelist.contradict2 -emit-llvm %t/test1.c -o - | FileCheck %s -check-prefix=CHECK-ALLOWLISTOVERIDE2
+
+
+// Verify ubsan only emits checks for files in the allowlist
+
+//--- src.ignorelist
+src:*
+src:*/test1.c=sanitize
+
+//--- src.ignorelist.contradict1
+src:*
+src:*/test1.c=sanitize
+src:*/test1.c
+
+//--- src.ignorelist.contradict2
+src:*
+src:*/test1.c
+src:*/test1.c=sanitize
+
+//--- test1.c
+int add1(int a, int b) {
+// CHECK-ALLOWLIST: llvm.sadd.with.overflow.i32
+// CHECK-ALLOWLISTOVERIDE1-NOT: llvm.sadd.with.overflow.i32
+// CHECK-ALLOWLISTOVERIDE2: llvm.sadd.with.overflow.i32
+    return a+b;
+}
+
+//--- test2.c
+int add2(int a, int b) {
+// CHECK-IGNORELIST-NOT: llvm.sadd.with.overflow.i32
+    return a+b;
+}