[compiler-rt] a1209d8 - [ubsan_minimal] Allow UBSan handler from Minimal runtime to accept arguments (#152192)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 6 11:21:52 PDT 2025
Author: Andrew Lazarev
Date: 2025-08-06T11:21:49-07:00
New Revision: a1209d868632b8aea10450cd2323848ab0b6776a
URL: https://github.com/llvm/llvm-project/commit/a1209d868632b8aea10450cd2323848ab0b6776a
DIFF: https://github.com/llvm/llvm-project/commit/a1209d868632b8aea10450cd2323848ab0b6776a.diff
LOG: [ubsan_minimal] Allow UBSan handler from Minimal runtime to accept arguments (#152192)
+ Changed type_mismatch minimal handler to accept and print pointer.
This will allow to distinguish null pointer use, misallignment and
incorrect object size.
The change increases binary size by ~1% and has almost no performance
impact.
Fixes #149943
Added:
compiler-rt/test/ubsan_minimal/TestCases/misalignment.cpp
compiler-rt/test/ubsan_minimal/TestCases/null.cpp
Modified:
clang/lib/CodeGen/CGExpr.cpp
compiler-rt/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 5a3d4e447b229..ed35a055d8a7f 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3789,33 +3789,50 @@ void CodeGenFunction::EmitCheck(
Branch->setMetadata(llvm::LLVMContext::MD_prof, Node);
EmitBlock(Handlers);
+ // Clear arguments for the MinimalRuntime handler.
+ if (CGM.getCodeGenOpts().SanitizeMinimalRuntime) {
+ switch (CheckHandler) {
+ case SanitizerHandler::TypeMismatch:
+ // Pass value pointer only. It adds minimal overhead.
+ StaticArgs = {};
+ assert(DynamicArgs.size() == 1);
+ break;
+ default:
+ // No arguments for other checks.
+ StaticArgs = {};
+ DynamicArgs = {};
+ break;
+ }
+ }
+
// Handler functions take an i8* pointing to the (handler-specific) static
// information block, followed by a sequence of intptr_t arguments
// representing operand values.
SmallVector<llvm::Value *, 4> Args;
SmallVector<llvm::Type *, 4> ArgTypes;
- if (!CGM.getCodeGenOpts().SanitizeMinimalRuntime) {
- Args.reserve(DynamicArgs.size() + 1);
- ArgTypes.reserve(DynamicArgs.size() + 1);
-
- // Emit handler arguments and create handler function type.
- if (!StaticArgs.empty()) {
- llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
- auto *InfoPtr = new llvm::GlobalVariable(
- CGM.getModule(), Info->getType(), false,
- llvm::GlobalVariable::PrivateLinkage, Info, "", nullptr,
- llvm::GlobalVariable::NotThreadLocal,
- CGM.getDataLayout().getDefaultGlobalsAddressSpace());
- InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
- CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
- Args.push_back(InfoPtr);
- ArgTypes.push_back(Args.back()->getType());
- }
- for (llvm::Value *DynamicArg : DynamicArgs) {
- Args.push_back(EmitCheckValue(DynamicArg));
- ArgTypes.push_back(IntPtrTy);
- }
+ Args.reserve(DynamicArgs.size() + 1);
+ ArgTypes.reserve(DynamicArgs.size() + 1);
+
+ // Emit handler arguments and create handler function type.
+ if (!StaticArgs.empty()) {
+ llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
+ auto *InfoPtr = new llvm::GlobalVariable(
+ CGM.getModule(), Info->getType(),
+ // Non-constant global is used in a handler to deduplicate reports.
+ // TODO: change deduplication logic and make it constant.
+ /*isConstant=*/false, llvm::GlobalVariable::PrivateLinkage, Info, "",
+ nullptr, llvm::GlobalVariable::NotThreadLocal,
+ CGM.getDataLayout().getDefaultGlobalsAddressSpace());
+ InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+ CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
+ Args.push_back(InfoPtr);
+ ArgTypes.push_back(Args.back()->getType());
+ }
+
+ for (llvm::Value *DynamicArg : DynamicArgs) {
+ Args.push_back(EmitCheckValue(DynamicArg));
+ ArgTypes.push_back(IntPtrTy);
}
llvm::FunctionType *FnType =
diff --git a/compiler-rt/lib/ubsan_minimal/ubsan_minimal_handlers.cpp b/compiler-rt/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
index ebc36a8583e05..b1f4eab26de0e 100644
--- a/compiler-rt/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
+++ b/compiler-rt/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
@@ -34,12 +34,16 @@ static char *append_hex(uintptr_t d, char *buf, const char *end) {
return buf;
}
-static void format_msg(const char *kind, uintptr_t caller, char *buf,
- const char *end) {
+static void format_msg(const char *kind, uintptr_t caller,
+ const uintptr_t *address, char *buf, const char *end) {
buf = append_str("ubsan: ", buf, end);
buf = append_str(kind, buf, end);
buf = append_str(" by 0x", buf, end);
buf = append_hex(caller, buf, end);
+ if (address) {
+ buf = append_str(" address 0x", buf, end);
+ buf = append_hex(*address, buf, end);
+ }
buf = append_str("\n", buf, end);
if (buf == end)
--buf; // Make sure we don't cause a buffer overflow.
@@ -47,7 +51,7 @@ static void format_msg(const char *kind, uintptr_t caller, char *buf,
}
SANITIZER_INTERFACE_WEAK_DEF(void, __ubsan_report_error, const char *kind,
- uintptr_t caller) {
+ uintptr_t caller, const uintptr_t *address) {
if (caller == 0)
return;
while (true) {
@@ -80,15 +84,15 @@ SANITIZER_INTERFACE_WEAK_DEF(void, __ubsan_report_error, const char *kind,
__sanitizer::atomic_store_relaxed(&caller_pcs[sz], caller);
char msg_buf[128];
- format_msg(kind, caller, msg_buf, msg_buf + sizeof(msg_buf));
+ format_msg(kind, caller, address, msg_buf, msg_buf + sizeof(msg_buf));
message(msg_buf);
}
}
SANITIZER_INTERFACE_WEAK_DEF(void, __ubsan_report_error_fatal, const char *kind,
- uintptr_t caller) {
+ uintptr_t caller, const uintptr_t *address) {
// Use another handlers, in case it's already overriden.
- __ubsan_report_error(kind, caller);
+ __ubsan_report_error(kind, caller, address);
}
#if defined(__ANDROID__)
@@ -121,13 +125,13 @@ void NORETURN CheckFailed(const char *file, int, const char *cond, u64, u64) {
#define HANDLER_RECOVER(name, kind) \
INTERFACE void __ubsan_handle_##name##_minimal() { \
- __ubsan_report_error(kind, GET_CALLER_PC()); \
+ __ubsan_report_error(kind, GET_CALLER_PC(), nullptr); \
}
#define HANDLER_NORECOVER(name, kind) \
INTERFACE void __ubsan_handle_##name##_minimal_abort() { \
uintptr_t caller = GET_CALLER_PC(); \
- __ubsan_report_error_fatal(kind, caller); \
+ __ubsan_report_error_fatal(kind, caller, nullptr); \
abort_with_message(kind, caller); \
}
@@ -135,7 +139,25 @@ void NORETURN CheckFailed(const char *file, int, const char *cond, u64, u64) {
HANDLER_RECOVER(name, kind) \
HANDLER_NORECOVER(name, kind)
-HANDLER(type_mismatch, "type-mismatch")
+#define HANDLER_RECOVER_PTR(name, kind) \
+ INTERFACE void __ubsan_handle_##name##_minimal(const uintptr_t address) { \
+ __ubsan_report_error(kind, GET_CALLER_PC(), &address); \
+ }
+
+#define HANDLER_NORECOVER_PTR(name, kind) \
+ INTERFACE void __ubsan_handle_##name##_minimal_abort( \
+ const uintptr_t address) { \
+ uintptr_t caller = GET_CALLER_PC(); \
+ __ubsan_report_error_fatal(kind, caller, &address); \
+ abort_with_message(kind, caller); \
+ }
+
+// A version of a handler that takes a pointer to a value.
+#define HANDLER_PTR(name, kind) \
+ HANDLER_RECOVER_PTR(name, kind) \
+ HANDLER_NORECOVER_PTR(name, kind)
+
+HANDLER_PTR(type_mismatch, "type-mismatch")
HANDLER(alignment_assumption, "alignment-assumption")
HANDLER(add_overflow, "add-overflow")
HANDLER(sub_overflow, "sub-overflow")
diff --git a/compiler-rt/test/ubsan_minimal/TestCases/misalignment.cpp b/compiler-rt/test/ubsan_minimal/TestCases/misalignment.cpp
new file mode 100644
index 0000000000000..cf828792a324f
--- /dev/null
+++ b/compiler-rt/test/ubsan_minimal/TestCases/misalignment.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_min_runtime -fsanitize=alignment %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
+
+void f(int &n) {}
+
+int *t;
+
+int main() {
+ int r;
+ t = (int *)(((char *)&r) + 1);
+ // CHECK: ubsan: type-mismatch by 0x{{[[:xdigit:]]+}} address 0x{{[[:xdigit:]]+$}}
+ // CHECK-NOT: type-mismatch
+ f(*t);
+}
diff --git a/compiler-rt/test/ubsan_minimal/TestCases/null.cpp b/compiler-rt/test/ubsan_minimal/TestCases/null.cpp
new file mode 100644
index 0000000000000..c97527b72cd0c
--- /dev/null
+++ b/compiler-rt/test/ubsan_minimal/TestCases/null.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_min_runtime -fsanitize=null %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
+
+void f(int &n) {}
+
+int *t;
+
+int main() {
+ // CHECK: ubsan: type-mismatch by 0x{{[[:xdigit:]]+}} address 0x{{[[:xdigit:]]+$}}
+ // CHECK-NOT: type-mismatch
+ f(*t);
+}
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