Remove jemalloc from the runtime

As discovered in #9925, it turns out that we weren't using jemalloc on most
platforms. Additionally, on some platforms we were using it incorrectly and
mismatching the libc version of malloc with the jemalloc version of malloc.

Additionally, it's not clear that using jemalloc is indeed a large performance
win in particular situtations. This could be due to building jemalloc
incorrectly, or possibly due to using jemalloc incorrectly, but it is unclear at
this time.

Until jemalloc can be confirmed to integrate correctly on all platforms and has
verifiable large performance wins on platforms as well, it shouldn't be part of
the default build process. It should still be available for use via the
LD_PRELOAD trick on various architectures, but using it as the default allocator
for everything would require guaranteeing that it works in all situtations,
which it currently doesn't.

Closes #9925

configure

@@ -684,7 +684,6 @@ do
     make_dir $t/rt/libuv/src/ares
     make_dir $t/rt/libuv/src/eio
     make_dir $t/rt/libuv/src/ev
-    make_dir $t/rt/jemalloc
     for i in                                          \
       isaac sync test \
       arch/i386 arch/x86_64 arch/arm arch/mips  \

mk/rt.mk

@@ -145,10 +145,10 @@ $$(RT_BUILD_DIR_$(1)_$(2))/arch/$$(HOST_$(1))/libmorestack.a: $$(MORESTACK_OBJ_$
 	$$(Q)$(AR_$(1)) rcs $$@ $$<
 
 $$(RT_BUILD_DIR_$(1)_$(2))/$(CFG_RUNTIME_$(1)): $$(RUNTIME_OBJS_$(1)_$(2)) $$(MKFILE_DEPS) \
-                        $$(RUNTIME_DEF_$(1)_$(2)) $$(LIBUV_LIB_$(1)) $$(JEMALLOC_LIB_$(1))
+                        $$(RUNTIME_DEF_$(1)_$(2)) $$(LIBUV_LIB_$(1))
 	@$$(call E, link: $$@)
 	$$(Q)$$(call CFG_LINK_CXX_$(1),$$@, $$(RUNTIME_OBJS_$(1)_$(2)) \
-	    $$(JEMALLOC_LIB_$(1)) $$(CFG_GCCISH_POST_LIB_FLAGS_$(1)) $$(LIBUV_LIB_$(1)) \
+	    $$(LIBUV_LIB_$(1)) \
 	    $$(CFG_LIBUV_LINK_FLAGS_$(1)),$$(RUNTIME_DEF_$(1)_$(2)),$$(CFG_RUNTIME_$(1)))
 
 # These could go in rt.mk or rustllvm.mk, they're needed for both.
@@ -197,27 +197,22 @@ define DEF_THIRD_PARTY_TARGETS
 # $(1) is the target triple
 
 RT_OUTPUT_DIR_$(1) := $(1)/rt
-JEMALLOC_TARGET_$(1) := jemalloc_pic
 
 ifeq ($$(CFG_WINDOWSY_$(1)), 1)
   LIBUV_OSTYPE_$(1) := win
-  JEMALLOC_TARGET_$(1) := jemalloc
 else ifeq ($(OSTYPE_$(1)), apple-darwin)
   LIBUV_OSTYPE_$(1) := mac
 else ifeq ($(OSTYPE_$(1)), unknown-freebsd)
   LIBUV_OSTYPE_$(1) := freebsd
 else ifeq ($(OSTYPE_$(1)), linux-androideabi)
   LIBUV_OSTYPE_$(1) := android
-  JEMALLOC_ARGS_$(1) := --disable-tls
   LIBUV_ARGS_$(1) := PLATFORM=android host=android OS=linux
 else
   LIBUV_OSTYPE_$(1) := linux
 endif
 
 LIBUV_NAME_$(1) := $$(call CFG_STATIC_LIB_NAME_$(1),uv)
 LIBUV_LIB_$(1) := $$(RT_OUTPUT_DIR_$(1))/libuv/$$(LIBUV_NAME_$(1))
-JEMALLOC_NAME_$(1) := $$(call CFG_STATIC_LIB_NAME_$(1),$$(JEMALLOC_TARGET_$(1)))
-JEMALLOC_LIB_$(1) := $$(RT_OUTPUT_DIR_$(1))/jemalloc/lib/$$(JEMALLOC_NAME_$(1))
 
 LIBUV_MAKEFILE_$(1) := $$(CFG_BUILD_DIR)$$(RT_OUTPUT_DIR_$(1))/libuv/Makefile
 
@@ -253,16 +248,6 @@ $$(LIBUV_LIB_$(1)): $$(LIBUV_DEPS) $$(LIBUV_MAKEFILE_$(1))
 		V=$$(VERBOSE)
 endif
 
-$$(JEMALLOC_LIB_$(1)):
-	cd $$(RT_OUTPUT_DIR_$(1))/jemalloc; $(S)src/rt/jemalloc/configure \
-		$$(JEMALLOC_ARGS_$(1)) \
-		--disable-experimental --build=$(CFG_BUILD_TRIPLE) --host=$(1) \
-		EXTRA_CFLAGS="$$(CFG_GCCISH_CFLAGS) $$(LIBUV_FLAGS_$$(HOST_$(1)))" \
-		CC="$$(CC_$(1))" \
-		CXX="$$(CXX_$(1))" \
-		AR="$$(AR_$(1))"
-	$$(Q)$$(MAKE) -C $$(RT_OUTPUT_DIR_$(1))/jemalloc build_lib_static
-
 endef
 
 # Instantiate template for all stages/targets

mk/tests.mk

@@ -265,7 +265,6 @@ tidy:
 		| grep '^$(S)src/libuv' -v \
 		| grep '^$(S)src/gyp' -v \
 		| grep '^$(S)src/etc' -v \
-		| grep '^$(S)src/rt/jemalloc' -v \
 		| xargs $(CFG_PYTHON) $(S)src/etc/check-binaries.py
 
 endif