[compiler-rt] 00be357 - [asan] Keep Itanium mangled names in global metadata
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 18 17:06:32 PST 2022
Author: Fangrui Song
Date: 2022-11-19T01:06:26Z
New Revision: 00be3578e0841dd9abe408e5b4946180de0bf46b
URL: https://github.com/llvm/llvm-project/commit/00be3578e0841dd9abe408e5b4946180de0bf46b
DIFF: https://github.com/llvm/llvm-project/commit/00be3578e0841dd9abe408e5b4946180de0bf46b.diff
LOG: [asan] Keep Itanium mangled names in global metadata
The runtime calls `MaybeDemangleGlobalName` for error reporting and
`__cxxabiv1::__cxa_demangle` is called if available, so demanging Itanium
mangled names in global metadata is unnecessary and wastes data size.
Add `MaybeDemangleGlobalName` in ODR violation detection to support demangled
names in a suppressions file. `MaybeDemangleGlobalName` may call
`DemangleCXXABI` and leak memory. Use an internal allocation to prevent lsan
leak (in case there is no fatal asan error).
The debug feature `report_globals=2` prints information for all instrumented
global variables. `MaybeDemangleGlobalName` would be slow, so don't do that.
The output looks like `Added Global[0x56448f092d60]: beg=0x56448fa66d60 size=4/32 name=_ZL13test_global_2`
and I think the mangled name is fine.
Other mangled schemes e.g. Windows (see win-string-literal.ll) remain the
current behavior.
Reviewed By: hctim
Differential Revision: https://reviews.llvm.org/D138095
Added:
Modified:
compiler-rt/lib/asan/asan_globals.cpp
compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
compiler-rt/test/asan/TestCases/Linux/odr_indicators.cpp
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
llvm/test/Instrumentation/AddressSanitizer/local_alias.ll
Removed:
################################################################################
diff --git a/compiler-rt/lib/asan/asan_globals.cpp b/compiler-rt/lib/asan/asan_globals.cpp
index b780128c9adb4..69b64dc129e27 100644
--- a/compiler-rt/lib/asan/asan_globals.cpp
+++ b/compiler-rt/lib/asan/asan_globals.cpp
@@ -148,9 +148,9 @@ static void CheckODRViolationViaIndicator(const Global *g) {
for (ListOfGlobals *l = list_of_all_globals; l; l = l->next) {
if (g->odr_indicator == l->g->odr_indicator &&
(flags()->detect_odr_violation >= 2 || g->size != l->g->size) &&
- !IsODRViolationSuppressed(g->name))
- ReportODRViolation(g, FindRegistrationSite(g),
- l->g, FindRegistrationSite(l->g));
+ !IsODRViolationSuppressed(MaybeDemangleGlobalName(g->name)))
+ ReportODRViolation(g, FindRegistrationSite(g), l->g,
+ FindRegistrationSite(l->g));
}
}
@@ -164,7 +164,7 @@ static void CheckODRViolationViaPoisoning(const Global *g) {
for (ListOfGlobals *l = list_of_all_globals; l; l = l->next) {
if (g->beg == l->g->beg &&
(flags()->detect_odr_violation >= 2 || g->size != l->g->size) &&
- !IsODRViolationSuppressed(g->name))
+ !IsODRViolationSuppressed(MaybeDemangleGlobalName(g->name)))
ReportODRViolation(g, FindRegistrationSite(g),
l->g, FindRegistrationSite(l->g));
}
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
index b223f6cd01e34..d505d96bd653a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
@@ -49,12 +49,17 @@ const char *DemangleCXXABI(const char *name) {
// FIXME: __cxa_demangle aggressively insists on allocating memory.
// There's not much we can do about that, short of providing our
// own demangler (libc++abi's implementation could be adapted so that
- // it does not allocate). For now, we just call it anyway, and we leak
- // the returned value.
- if (&__cxxabiv1::__cxa_demangle)
- if (const char *demangled_name =
- __cxxabiv1::__cxa_demangle(name, 0, 0, 0))
- return demangled_name;
+ // it does not allocate). For now, we just call it anyway, and use
+ // InternalAlloc to prevent lsan error.
+ if (&__cxxabiv1::__cxa_demangle) {
+ if (char *demangled_name = __cxxabiv1::__cxa_demangle(name, 0, 0, 0)) {
+ size_t size = internal_strlen(demangled_name) + 1;
+ char *buf = (char *)InternalAlloc(size);
+ internal_memcpy(buf, demangled_name, size);
+ free(demangled_name);
+ return buf;
+ }
+ }
return name;
}
diff --git a/compiler-rt/test/asan/TestCases/Linux/odr_indicators.cpp b/compiler-rt/test/asan/TestCases/Linux/odr_indicators.cpp
index 583f6e662fda8..cef6b99521391 100644
--- a/compiler-rt/test/asan/TestCases/Linux/odr_indicators.cpp
+++ b/compiler-rt/test/asan/TestCases/Linux/odr_indicators.cpp
@@ -11,11 +11,11 @@ int test_global_1;
// INDICATOR1-DAG: Added Global{{.*}} name=test_global_1{{.*}} odr_indicator={{0x0*[^0]+.*$}}
static int test_global_2;
-// CHECK-DAG: Added Global{{.*}} name=test_global_2{{.*}} odr_indicator={{0xf+$}}
+// CHECK-DAG: Added Global{{.*}} name=_ZL13test_global_2 {{.*}} odr_indicator={{0xf+$}}
namespace {
static int test_global_3;
-// CHECK-DAG: Added Global{{.*}} name={{.*}}::test_global_3{{.*}} odr_indicator={{0xf+$}}
+// CHECK-DAG: Added Global{{.*}} name=_ZN12_GLOBAL__N_113test_global_3E {{.*}} odr_indicator={{0xf+$}}
} // namespace
int main() {
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index ff05454aa920e..bc8823ad5ceb5 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2264,9 +2264,11 @@ bool ModuleAddressSanitizer::InstrumentGlobals(IRBuilder<> &IRB, Module &M,
if (G->hasSanitizerMetadata())
MD = G->getSanitizerMetadata();
- // TODO: Symbol names in the descriptor can be demangled by the runtime
- // library. This could save ~0.4% of VM size for a private large binary.
- std::string NameForGlobal = llvm::demangle(G->getName().str());
+ // ASan runtime demangles Itanium mangled names, so keep the original name
+ // to prevent unneeded size increase of the string table.
+ std::string NameForGlobal = G->getName().str();
+ if (!StringRef(NameForGlobal).startswith("_Z"))
+ NameForGlobal = llvm::demangle(NameForGlobal);
GlobalVariable *Name =
createPrivateGlobalForString(M, NameForGlobal,
/*AllowMerging*/ true, kAsanGenPrefix);
diff --git a/llvm/test/Instrumentation/AddressSanitizer/local_alias.ll b/llvm/test/Instrumentation/AddressSanitizer/local_alias.ll
index b772d5c76167c..550c2f1e9d667 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/local_alias.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/local_alias.ll
@@ -13,17 +13,20 @@ target triple = "x86_64-unknown-linux-gnu"
@a = dso_local global [2 x i32] zeroinitializer, align 4
@b = private global [2 x i32] zeroinitializer, align 4
@c = internal global [2 x i32] zeroinitializer, align 4
- at d = unnamed_addr global [2 x i32] zeroinitializer, align 4
+ at _ZL1d = unnamed_addr global [2 x i32] zeroinitializer, align 4
; Check that we generate internal alias and odr indicator symbols for global to be protected.
; CHECK-NOINDICATOR-NOT: __odr_asan_gen_a
; CHECK-NOALIAS-NOT: private alias
+; CHECK-INDICATOR: @___asan_gen_.1 = private unnamed_addr constant [2 x i8] c"a\00", align 1
; CHECK-INDICATOR: @__odr_asan_gen_a = global i8 0, align 1
+; CHECK-INDICATOR: @___asan_gen_.4 = private unnamed_addr constant [6 x i8] c"_ZL1d\00", align 1
+; CHECK-INDICATOR: @__odr_asan_gen__ZL1d = global i8 0, align 1
; CHECK-ALIAS: @0 = private alias { [2 x i32], [24 x i8] }, ptr @a
; CHECK-ALIAS: @1 = private alias { [2 x i32], [24 x i8] }, ptr @b
; CHECK-ALIAS: @2 = private alias { [2 x i32], [24 x i8] }, ptr @c
-; CHECK-ALIAS: @3 = private alias { [2 x i32], [24 x i8] }, ptr @d
+; CHECK-ALIAS: @3 = private alias { [2 x i32], [24 x i8] }, ptr @_ZL1d
; Function Attrs: nounwind sanitize_address uwtable
define i32 @foo(i32 %M) #0 {
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