[scudo] Optimize scudo test string allocation
When the underlying vector becomes full, it resizes, remaps, and then copies over the old data. To avoid thes excess allocations, allow reservation from the backing vector.
Differential Revision: https://reviews.llvm.org/D135119
GitOrigin-RevId: 119f977d9e3f8af9f5ac54270e828e354452f903
Change-Id: I33e6d3008cd19c5b0410703b7319e5b12d14fe8e
diff --git a/standalone/string_utils.h b/standalone/string_utils.h
index dd6ff78..4190119 100644
--- a/standalone/string_utils.h
+++ b/standalone/string_utils.h
@@ -28,6 +28,7 @@
void append(const char *Format, va_list Args);
void append(const char *Format, ...) FORMAT(2, 3);
void output() const { outputRaw(String.data()); }
+ void reserve(size_t Size) { String.reserve(Size + 1); }
private:
Vector<char> String;
diff --git a/standalone/tests/strings_test.cpp b/standalone/tests/strings_test.cpp
index 6d7e78a..7a69ffd 100644
--- a/standalone/tests/strings_test.cpp
+++ b/standalone/tests/strings_test.cpp
@@ -43,9 +43,11 @@
}
TEST(ScudoStringsTest, ClearLarge) {
+ constexpr char appendString[] = "123";
scudo::ScopedString Str;
+ Str.reserve(sizeof(appendString) * 10000);
for (int i = 0; i < 10000; ++i)
- Str.append("123");
+ Str.append(appendString);
Str.clear();
EXPECT_EQ(0ul, Str.length());
EXPECT_EQ('\0', *Str.data());
@@ -76,6 +78,7 @@
// of it with variations of append. The expectation is for nothing to crash.
const scudo::uptr PageSize = scudo::getPageSizeCached();
scudo::ScopedString Str;
+ Str.reserve(2 * PageSize);
Str.clear();
fillString(Str, 2 * PageSize);
Str.clear();
