Support prefixed jemalloc when USE_JEMALLOC is enabled

CMakeLists.txt

@@ -300,6 +300,11 @@ if (FOLLY_HAVE_OPENSSL)
   )
 endif ()
 
+if (FOLLY_USE_JEMALLOC)
+  # Consumers may include jemalloc before a Folly header.
+  target_compile_definitions(folly_deps INTERFACE JEMALLOC_NO_DEMANGLE)
+endif ()
+
 # Generate pkg-config variables from folly_deps before we add our own
 # build/install-time include directory generator expressions
 include(GenPkgConfig)
@@ -1488,6 +1493,10 @@ if (BUILD_TESTS OR BUILD_BENCHMARKS)
     SOURCES
     MallctlHelperTest.cpp
     TEST
+    memory_malloc_test
+    SOURCES
+    MallocTest.cpp
+    TEST
     memory_uninitialized_test
     SOURCES
     UninitializedTest.cpp

folly/memory/test/MallocTest.cpp

@@ -17,6 +17,8 @@
 #include <folly/memory/Malloc.h>
 
 #include <cstdint>
+#include <cstdlib>
+#include <cstring>
 #include <limits>
 #include <new>
 #include <stdexcept>
@@ -26,6 +28,17 @@
 
 namespace folly {
 
+TEST(MallocTest, standardAllocationAndSizedFree) {
+  for (size_t requested : {1, 64, 4096, 65536}) {
+    size_t size = goodMallocSize(requested);
+    ASSERT_GE(size, requested);
+    void* ptr = std::malloc(size);
+    ASSERT_NE(ptr, nullptr);
+    std::memset(ptr, 0xA5, size);
+    sizedFree(ptr, size);
+  }
+}
+
 TEST(MallocTest, getJEMallocMallctlArenasAll) {
 #if FOLLY_HAS_JEMALLOC_DEFS
   EXPECT_EQ(4096, getJEMallocMallctlArenasAll());

folly/portability/Malloc.h

@@ -33,8 +33,33 @@
 #include <malloc_np.h> // @manual
 #define FOLLY_HAS_JEMALLOC_DEFS 0
 #else
+// Keep jemalloc's stable API aliases without remapping malloc/free macros.
+#ifndef JEMALLOC_NO_DEMANGLE
+#define JEMALLOC_NO_DEMANGLE
+#endif
 #include <jemalloc/jemalloc.h> // @manual
 #define FOLLY_HAS_JEMALLOC_DEFS 1
+
+#ifdef USE_JEMALLOC
+// Explicit jemalloc builds can bind its helpers directly. Leave the weak-symbol
+// path unchanged when the allocator is selected at runtime (e.g. TCMalloc).
+namespace folly {
+inline constexpr auto malloc_usable_size = ::je_malloc_usable_size;
+inline constexpr auto mallocx = ::je_mallocx;
+inline constexpr auto rallocx = ::je_rallocx;
+inline constexpr auto xallocx = ::je_xallocx;
+inline constexpr auto sallocx = ::je_sallocx;
+inline constexpr auto dallocx = ::je_dallocx;
+inline constexpr auto sdallocx = ::je_sdallocx;
+inline constexpr auto nallocx = ::je_nallocx;
+inline constexpr auto mallctl = ::je_mallctl;
+inline constexpr auto mallctlnametomib = ::je_mallctlnametomib;
+inline constexpr auto mallctlbymib = ::je_mallctlbymib;
+#ifdef je_free_aligned_sized
+inline constexpr auto free_aligned_sized = ::je_free_aligned_sized;
+#endif
+} // namespace folly
+#endif
 #endif
 #else
 #if !defined(__FreeBSD__)