diff --git a/.gitignore b/.gitignore
index 584e2abf771..4b9b46b5872 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,7 +16,6 @@
 # generated by build and tests
 /_build
 /_build_logs
-/infer/_build
 /infer/tests/codetoanalyze/java/*/codetoanalyze
 /dependencies/infer-deps-*
 _build_infer
@@ -93,8 +92,8 @@ buck-out/
 
 #other
 /infer/bin/infer
-/infer/bin/infer.byte
-/infer/bin/infer.native
+/infer/bin/infer.bc
+/infer/bin/infer.exe
 /infer/bin/infer-analyze
 /infer/bin/infer-capture
 /infer/bin/infer-compile
@@ -151,3 +150,9 @@ infer/src/.project
 
 # generated by Maven
 /infer/annotations/target
+
+# jbuilder
+/infer/src/_build
+/infer/src/jbuild
+/infer/src/jbuild-workspace
+/infer/src/scripts/.merlin
diff --git a/Makefile b/Makefile
index 5cd1f38b36c..c1d55b2a556 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,11 @@ default: infer
 ROOT_DIR = .
 include $(ROOT_DIR)/Makefile.config
 
+ifneq ($(UTOP),no)
+BUILD_SYSTEMS_TESTS += infertop
+build_infertop_print build_infertop_replace build_infertop_test: toplevel_test
+endif
+
 ifeq ($(BUILD_C_ANALYZERS),yes)
 BUILD_SYSTEMS_TESTS += \
   assembly \
@@ -81,8 +86,8 @@ endif
 ifneq ($(BUCK),no)
 BUILD_SYSTEMS_TESTS += buck genrule
 # do not run these two tests in parallel otherwise Buck has a bad time
-build_genrule_test: build_buck_test
-build_genrule_print: build_buck_print
+build_genrule_test: | build_buck_test
+build_genrule_print: | build_buck_print
 endif
 ifneq ($(MVN),no)
 BUILD_SYSTEMS_TESTS += mvn
@@ -149,14 +154,9 @@ byte: src_build_common
 test_build: src_build_common
 	$(QUIET)$(call silent_on_success,Testing Infer builds without warnings,\
 	$(MAKE) -C $(SRC_DIR) TEST=1 byte_no_install)
-#	byte_no_install builds most of what toplevel needs, so it's more efficient to run the
-#	toplevel build straight after it rather than in parallel. Note that both targets build files
-#	that the other doesn't.
-	$(QUIET)$(call silent_on_success,Testing Infer toplevel builds,\
-	$(MAKE) -C $(SRC_DIR) TEST=1 toplevel)
 
 ifeq ($(IS_FACEBOOK_TREE),yes)
-byte src_build test_build: fb-setup
+byte src_build_common src_build test_build: fb-setup
 endif
 
 ifeq ($(BUILD_C_ANALYZERS),yes)
@@ -219,7 +219,7 @@ endif
 .PHONY: ocaml_unit_test
 ocaml_unit_test: test_build
 	$(QUIET)$(call silent_on_success,Running OCaml unit tests,\
-	$(BUILD_DIR)/test/infer/unit/inferunit.byte)
+	$(BUILD_DIR)/test/inferunit.bc)
 
 define silence_make
   ($(1) 2> >(grep -v "warning: \(ignoring old\|overriding\) \(commands\|recipe\) for target") \
@@ -296,15 +296,17 @@ check_missing_mli:
 	$(QUIET)for x in $$(find $(INFER_DIR)/src -name "*.ml"); do \
 	    test -f "$$x"i || echo Missing "$$x"i; done
 
-.PHONY: toplevel
-toplevel: clang_plugin src_build_common
-	$(QUIET)$(MAKE) -C $(SRC_DIR) toplevel
+# depend on test_build because jbuilder doesn't like running concurrently with itself
+.PHONY: toplevel_test
+toplevel_test: src_build_common | test_build
+#	build with TEST=1 as the infer_repl scripts expects to find the toplevel in the test build
+	$(QUIET)$(call silent_on_success,Building infer toplevel (test mode),\
+	$(MAKE) -C $(SRC_DIR) TEST=1 toplevel)
 
-.PHONY: inferScriptMode_test
-inferScriptMode_test: test_build
-	$(QUIET)$(call silent_on_success,Testing infer OCaml REPL,\
-	INFER_REPL_BINARY=ocaml TOPLEVEL_DIR=$(BUILD_DIR)/test/infer $(SCRIPT_DIR)/infer_repl \
-	  $(INFER_DIR)/tests/repl/infer_batch_script.mltop)
+.PHONY: toplevel
+toplevel: src_build_common
+	$(QUIET)$(call silent_on_success,Building infer toplevel,\
+	$(MAKE) -C $(SRC_DIR) toplevel)
 
 .PHONY: checkCopyright
 checkCopyright:
@@ -342,8 +344,7 @@ else
 endif
 
 .PHONY: config_tests
-config_tests: test_build ocaml_unit_test endtoend_test inferScriptMode_test \
-      checkCopyright validate-skel
+config_tests: test_build ocaml_unit_test endtoend_test checkCopyright validate-skel
 	$(QUIET)$(call silent_on_success,Building Infer source dependency graph,\
 	$(MAKE) -C $(SRC_DIR) mod_dep.dot)
 
@@ -550,7 +551,10 @@ opam.lock: opam
 	$(QUIET)$(call silent_on_success,generating opam.lock,\
 	  $(OPAM) lock --pkg  $(INFER_PKG_OPAMLOCK) > opam.lock)
 
-OPAM_DEV_DEPS = ocp-indent merlin tuareg
+# This is a magical version number that doesn't reinstall the world when added on top of what we
+# have in opam.lock. To upgrade this version number, manually try to install several utop versions
+# until you find one that doesn't recompile the world. TODO(t20828442): get rid of magic
+OPAM_DEV_DEPS = ocp-indent merlin tuareg utop.2.0.0
 
 .PHONY: devsetup
 devsetup: Makefile.autoconf
diff --git a/Makefile.autoconf.in b/Makefile.autoconf.in
index c733943cf5c..da2aa8544ae 100644
--- a/Makefile.autoconf.in
+++ b/Makefile.autoconf.in
@@ -64,6 +64,7 @@ prefix = @prefix@
 PYTHON_lxml = @PYTHON_lxml@
 SHASUM = @SHASUM@
 USER_JAVA_HOME = @USER_JAVA_HOME@
+UTOP = @UTOP@
 XCODE_SELECT = @XCODE_SELECT@
 XCPRETTY = @XCPRETTY@
 
diff --git a/Makefile.config b/Makefile.config
index 7a36026d4ca..069dc07890c 100644
--- a/Makefile.config
+++ b/Makefile.config
@@ -45,7 +45,7 @@ JAVA_BUILTINS_DIR = $(MODELS_DIR)/java/builtins
 JAVA_MODELS_DIR = $(MODELS_DIR)/java/src
 SRC_DIR = $(INFER_DIR)/src
 
-BUILD_DIR = $(INFER_DIR)/_build
+BUILD_DIR = $(SRC_DIR)/_build
 
 JAVA_LIB_DIR = $(LIB_DIR)/java
 SPECS_LIB_DIR = $(LIB_DIR)/specs
diff --git a/configure.ac b/configure.ac
index 3a226476acf..79758dfc4c6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -187,6 +187,7 @@ AC_ASSERT_OCAML_PKG([biniou])
 AC_ASSERT_OCAML_PKG([camlzip], [zip])
 AC_ASSERT_OCAML_PKG([easy-format])
 AC_ASSERT_OCAML_PKG([oUnit], [], [2.0.0])
+AC_CHECK_TOOL([UTOP], [utop], [no])
 AC_ASSERT_OCAML_PKG([yojson])
 
 AC_ARG_VAR([CAML_LD_LIBRARY_PATH],
diff --git a/infer/.merlin b/infer/.merlin
deleted file mode 100644
index 7f6e6831442..00000000000
--- a/infer/.merlin
+++ /dev/null
@@ -1,20 +0,0 @@
-S src/**
-B _build/infer/**
-B _build/test/infer/unit/**
-PKG ANSITerminal
-PKG atdgen
-PKG cmdliner
-PKG core
-PKG javalib
-PKG oUnit
-PKG parmap
-PKG ppx_compare
-PKG ptrees
-PKG sawja
-PKG str
-PKG unix
-PKG xmlm
-PKG yojson
-PKG zip
-FLG -principal -safe-string -short-paths -strict-formats -strict-sequence
-FLG -w +a-4-9-40-41-42-45-48
diff --git a/infer/src/.merlin b/infer/src/.merlin
new file mode 100644
index 00000000000..6822d2620cd
--- /dev/null
+++ b/infer/src/.merlin
@@ -0,0 +1,38 @@
+B _build/default/**
+PKG ANSITerminal
+PKG atdgen
+PKG cmdliner
+PKG core
+PKG javalib
+PKG oUnit
+PKG parmap
+PKG ppx_compare
+PKG ptrees
+PKG sawja
+PKG str
+PKG unix
+PKG xmlm
+PKG yojson
+PKG zip
+FLG -principal -safe-string -short-paths -strict-formats -strict-sequence
+FLG -w +a-4-9-40-41-42-45-48
+FLG -open InferBaseStdlib -open InferGenerated -open InferModules
+S backend
+S base
+S bufferoverrun
+S checkers
+S clang
+S clang_plugin
+S clang_stubs
+S eradicate
+S facebook
+S harness
+S integration
+S IR
+S java
+S java_stubs
+S labs
+S opensource
+S quandary
+S scripts
+S unit
diff --git a/infer/src/IR/BUILTINS.mli b/infer/src/IR/BUILTINS.ml
similarity index 100%
rename from infer/src/IR/BUILTINS.mli
rename to infer/src/IR/BUILTINS.ml
diff --git a/infer/src/Makefile b/infer/src/Makefile
index f5277d7b78a..3224a0a94a0 100644
--- a/infer/src/Makefile
+++ b/infer/src/Makefile
@@ -11,61 +11,20 @@ include $(ROOT_DIR)/Makefile.config
 #### Global declarations ####
 
 ETC_DIR = $(INFER_DIR)/etc
+# paths to BUILD_DIR are relative because that's how jbuilder likes it
+JBUILDER_BUILD_DEFAULT = _build/default
+JBUILDER_BUILD_TEST = _build/test
 ifeq ($(TEST),1)
-BASE_BUILD_DIR = $(BUILD_DIR)/test
+INFER_BUILD_DIR = $(JBUILDER_BUILD_TEST)
 else
-BASE_BUILD_DIR = $(BUILD_DIR)
+INFER_BUILD_DIR = $(JBUILDER_BUILD_DEFAULT)
 endif
-INFER_BUILD_DIR = $(BASE_BUILD_DIR)/infer
 
 ATDGEN_SUFFIXES = _t.ml _t.mli _j.ml _j.mli
 
-#### ocamlbuild options ####
-
-GENERATED_OCAML_SOURCES_GLOB = <*{clang_plugin/*,backend/jsonbug_*,checkers/stacktree_*}>
-
-OCAML_FATAL_WARNINGS = +3+5+6+8+10+11+12+18+19+20+21+23+26+29+27+32+33+34+35+37+38+39+50+52+57
-
-# options for ocamlbuild
-# Notice that use-ocamlfind is used here to avoid a linker bug in ocamlbuild when using -tag thread
-OCAMLBUILD_OPTIONS = \
-  -r \
-  -use-menhir -menhir '$(MENHIR) --explain --strict'\
-  -use-ocamlfind \
-  -cflags -g -lflags -g \
-  -cflags -short-paths \
-  -cflags -safe-string \
-  -cflags -principal \
-  -cflags -strict-formats \
-  -cflags -strict-sequence \
-  -cflags -w,$(OCAML_FATAL_WARNINGS)-4-9-40-41-42-45-48 \
-  -tag-line "$(GENERATED_OCAML_SOURCES_GLOB): warn(-27-32-34-35-39)" \
-  -tag-line "not $(GENERATED_OCAML_SOURCES_GLOB) and <*/{,*/}*.{ml,re}{,i}>: package(ppx_compare)" \
-  -tag-line "not $(GENERATED_OCAML_SOURCES_GLOB) and not <*{base/IList,base/IStd}.*>: open(IStd)" \
-  -tag thread \
-  -pkgs ANSITerminal,atdgen,cmdliner,core,extlib,oUnit,parmap,str,unix,xmlm,yojson,zip
-
-ifeq ($(ENABLE_OCAML_BINANNOT),yes)
-OCAMLBUILD_OPTIONS += -cflags -bin-annot
-endif
-
-ifeq ($(ENABLE_OCAMLOPT_CUSTOM_CC),yes)
-OCAMLBUILD_OPTIONS += -lflags -cc,$(CC) -cflags -cc,$(CC)
-endif
-
-ifneq (,$(findstring s,$(MAKEFLAGS)))
-OCAMLBUILD_OPTIONS += -quiet
-endif
-
-ifeq ($(TEST),1)
-OCAMLBUILD_OPTIONS += -cflags -warn-error,$(OCAML_FATAL_WARNINGS)
-endif
-
-export OCAMLFIND_IGNORE_DUPS_IN=$(shell $(OCAMLC) -where)/compiler-libs
-
 #### Backend declarations ####
 
-INFER_MAIN = backend/infer
+INFER_MAIN = infer
 
 #### Checkers declarations ####
 
@@ -83,18 +42,16 @@ INFERPRINT_ATDGEN_STUBS = $(addprefix $(INFERPRINT_ATDGEN_STUB_BASE), $(ATDGEN_S
 
 FACEBOOK_DIR = facebook
 INFER_CREATE_TRACEVIEW_LINKS_MODULE = InferCreateTraceViewLinks
-INFER_CREATE_TRACEVIEW_LINKS_MAIN = $(FACEBOOK_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MODULE)
+INFER_CREATE_TRACEVIEW_LINKS_MAIN = $(INFER_CREATE_TRACEVIEW_LINKS_MODULE)
 
 ### InferUnit declarations ###
 
 UNIT_SOURCES = unit
 
-INFERUNIT_MAIN = $(UNIT_SOURCES)/inferunit
+INFERUNIT_MAIN = inferunit
 
 #### Java declarations ####
 
-JAVA_OCAMLBUILD_OPTIONS = -pkgs javalib,ptrees,sawja
-
 JAVA_SOURCES = java
 
 #### Clang declarations ####
@@ -127,65 +84,44 @@ CLANG_BINIOU_DICT = $(ETC_DIR)/clang_ast.dict
 SCRIPT_SOURCES = scripts
 
 CHECKCOPYRIGHT_BIN = $(SCRIPT_DIR)/checkCopyright
-CHECKCOPYRIGHT_MAIN = $(SCRIPT_SOURCES)/checkCopyright
+CHECKCOPYRIGHT_MAIN = checkCopyright
 
 #### End of declarations ####
 
-ifeq ($(IS_FACEBOOK_TREE),yes)
-EXTRA_DEPS = facebook
-else
-EXTRA_DEPS = opensource
+ifeq ($(ENABLE_OCAMLOPT_CUSTOM_CC),yes)
+EXTRA_CFLAGS += -cc,$(CC)
 endif
 
-DEPENDENCIES = \
-  absint backend base bufferoverrun checkers eradicate harness integration IR labs quandary unit \
-  $(EXTRA_DEPS)
-
-# ocamlbuild command with options common to all build targets
-OCAMLBUILD_BASE = \
-  $(OCAMLBUILD) $(OCAMLBUILD_OPTIONS) -j $(NCPU) $(addprefix -I , $(DEPENDENCIES)) \
-
-# ocamlbuild with options necessary to build all targets at once, regardless of configure flags
-OCAMLBUILD_ALL = $(OCAMLBUILD_BASE) $(JAVA_OCAMLBUILD_OPTIONS)
-
-# configure-aware ocamlbuild commands and targets
-OCAMLBUILD_CONFIG = $(OCAMLBUILD_BASE)
 # list of ocamlbuild targets common to all build targets -- native version
-INFER_CONFIG_TARGETS = $(INFER_MAIN).native
+INFER_CONFIG_TARGETS = $(INFER_BUILD_DIR)/$(INFER_MAIN).exe
 ifeq ($(IS_FACEBOOK_TREE),yes)
-INFER_CONFIG_TARGETS += $(INFER_CREATE_TRACEVIEW_LINKS_MAIN).native
+INFER_CONFIG_TARGETS += $(INFER_BUILD_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MAIN).exe
 endif
 
-ifeq ($(BUILD_JAVA_ANALYZERS),yes)
-OCAMLBUILD_CONFIG += $(JAVA_OCAMLBUILD_OPTIONS)
-DEPENDENCIES += java
-else
-DEPENDENCIES += java_stubs
-endif
-ifeq ($(BUILD_C_ANALYZERS),yes)
-DEPENDENCIES += clang clang_plugin unit/clang
-else
-DEPENDENCIES += clang_stubs unit/clang_stubs
-endif
 ifeq ($(TEST),1)
-INFER_CONFIG_TARGETS += $(INFERUNIT_MAIN).native
+INFER_CONFIG_TARGETS += $(INFER_BUILD_DIR)/$(INFERUNIT_MAIN).exe
 endif
 
-OCAML_BASE_SOURCES = \
-  $(wildcard $(DEPENDENCIES:=/[a-zA-Z]*.ml) $(DEPENDENCIES:=/[a-zA-Z]*.mli) \
-             $(DEPENDENCIES:=/[a-zA-Z]*.mll) $(DEPENDENCIES:=/[a-zA-Z]*.mly) \
-             $(DEPENDENCIES:=/[a-zA-Z]*.re) $(DEPENDENCIES:=/[a-zA-Z]*.rei)) \
-  $(STACKTREE_ATDGEN_STUBS) $(INFERPRINT_ATDGEN_STUBS)
-OCAML_CONFIG_SOURCES = $(OCAML_BASE_SOURCES)
+OCAML_SOURCES = \
+  $(wildcard */[a-zA-Z]*.ml */[a-zA-Z]*.ml[ily]) \
+  base/Version.ml $(STACKTREE_ATDGEN_STUBS) $(INFERPRINT_ATDGEN_STUBS)
+
 ifeq ($(BUILD_C_ANALYZERS),yes)
-OCAML_CONFIG_SOURCES += $(CLANG_ATDGEN_STUBS) $(CLANG_PLUGIN_MIRRORED_FILES)
+OCAML_SOURCES += $(CLANG_ATDGEN_STUBS) $(CLANG_PLUGIN_MIRRORED_FILES)
 endif
-OCAML_ALL_SOURCES = $(OCAML_BASE_SOURCES) $(CLANG_ATDGEN_STUBS) $(CLANG_PLUGIN_MIRRORED_FILES)
 
 .PHONY: all
 all: infer
 
-SRC_BUILD_COMMON = base/Version.ml $(OCAML_CONFIG_SOURCES)
+$(INFER_BUILD_DIR)/.ppx/ppx_compare/ppx.exe: jbuild jbuild-workspace $(OCAML_SOURCES)
+#      some voodoo to make jbuilder tolerate being run in parallel: force jbuilder to build its
+#      jbuild files and some files that have been seen to race otherwise
+	jbuilder build \
+	  $(JBUILDER_BUILD_DEFAULT)/.ppx/ppx_compare/ppx.exe \
+	  $(JBUILDER_BUILD_TEST)/.ppx/ppx_compare/ppx.exe
+	touch $@
+
+SRC_BUILD_COMMON = $(INFER_BUILD_DIR)/.ppx/ppx_compare/ppx.exe $(OCAML_SOURCES)
 ifeq ($(BUILD_C_ANALYZERS),yes)
 SRC_BUILD_COMMON += $(CLANG_BINIOU_DICT)
 endif
@@ -193,12 +129,10 @@ endif
 .PHONY: src_build_common
 src_build_common: $(SRC_BUILD_COMMON)
 
-# single out infer.native as the source of truth for make, knowing that in fact several targets are
+# single out infer.exe as the source of truth for make, knowing that in fact several targets are
 # produced by the build
-$(INFER_BUILD_DIR)/$(INFER_MAIN).native: $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
-	$(MKDIR_P) $(BASE_BUILD_DIR)
-	$(OCAMLBUILD_CONFIG) -build-dir $(INFER_BUILD_DIR) \
-	  $(INFER_CONFIG_TARGETS)
+$(INFER_BUILD_DIR)/$(INFER_MAIN).exe: $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
+	jbuilder build $(INFER_CONFIG_TARGETS)
 #	let make know that the target is up-to-date even if ocamlbuild cached it
 	$(QUIET)touch $@
 
@@ -210,59 +144,38 @@ $(INFER_BIN_ALIASES): Makefile
 	$(QUIET)cd $(@D) && $(LN_S) -f infer $(@F)
 	$(QUIET)touch $@
 
-$(INFER_BIN).native: $(INFER_BUILD_DIR)/$(INFER_MAIN).native $(INFER_BIN_ALIASES)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).native $(INFER_BIN)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).native $(INFER_BIN).native
+$(INFER_BIN).exe: $(INFER_BUILD_DIR)/$(INFER_MAIN).exe $(INFER_BIN_ALIASES)
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).exe $(INFER_BIN)
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).exe $(INFER_BIN).exe
 ifeq ($(IS_FACEBOOK_TREE),yes)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MAIN).native \
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MAIN).exe \
 		$(INFER_CREATE_TRACEVIEW_LINKS_BIN)
 endif
 
 
 .PHONY: infer
-infer: $(INFER_BIN).native
+infer: $(INFER_BIN).exe
 
-$(INFER_BUILD_DIR)/$(INFER_MAIN).byte: $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
-	$(MKDIR_P) $(BASE_BUILD_DIR)
-	$(OCAMLBUILD_CONFIG) -build-dir $(INFER_BUILD_DIR) \
-	  $(INFER_CONFIG_TARGETS:.native=.byte)
+$(INFER_BUILD_DIR)/$(INFER_MAIN).bc: $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
+	jbuilder build $(INFER_CONFIG_TARGETS:.exe=.bc)
 	$(QUIET)touch $@
 
-$(INFER_BIN).byte: $(INFER_BUILD_DIR)/$(INFER_MAIN).byte $(INFER_BIN_ALIASES)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).byte $(INFER_BIN)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).byte $(INFER_BIN).byte
+$(INFER_BIN).bc: $(INFER_BUILD_DIR)/$(INFER_MAIN).bc $(INFER_BIN_ALIASES)
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).bc $(INFER_BIN)
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_MAIN).bc $(INFER_BIN).bc
 ifeq ($(TEST),1)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFERUNIT_MAIN).byte $(INFERUNIT_BIN)
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFERUNIT_MAIN).bc $(INFERUNIT_BIN)
 endif
 ifeq ($(IS_FACEBOOK_TREE),yes)
-	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MAIN).byte \
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(INFER_CREATE_TRACEVIEW_LINKS_MAIN).bc \
 		$(INFER_CREATE_TRACEVIEW_LINKS_BIN)
 endif
 
 .PHONY: byte
-byte: $(INFER_BIN).byte
+byte: $(INFER_BIN).bc
 
 .PHONY: byte_no_install
-byte_no_install: $(INFER_BUILD_DIR)/$(INFER_MAIN).byte
-
-# to build only the single module <Module> (and its dependencies) with extra flags execute:
-#   make MFLAGS=<flags> M=<Module>.cm{o,x} module
-# for example, to build the assembly for the Ident module, execute
-#   make MFLAGS="-ocamlopt 'ocamlopt -S'" M=Ident.cmx module
-M=
-MFLAGS=
-
-.PHONY: module
-module: $(SRC_BUILD_COMMON) $(OCAML_ALL_SOURCES)
-	$(MKDIR_P) $(BASE_BUILD_DIR)
-	$(OCAMLBUILD_ALL) -build-dir $(INFER_BUILD_DIR) \
-          $(MFLAGS) \
-	  $(M)
-
-# to generate interface file.mli from implementation file.ml execute:
-#   make M=file mli
-mli:
-	$(OCAMLFIND) ocamlc -package atdgen,oUnit,str,unix,yojson,zip $(addprefix -I $(INFER_BUILD_DIR),$(DEPENDENCIES)) -i $(M).ml > $(M).mli
+byte_no_install: $(INFER_BUILD_DIR)/$(INFER_MAIN).bc
 
 roots:=Infer
 ifeq ($(IS_FACEBOOK_TREE),yes)
@@ -270,8 +183,8 @@ roots += $(INFER_CREATE_TRACEVIEW_LINKS_MODULE)
 endif
 clusters:=base clang java IR
 
-ml_src_files:=$(shell find $(DEPENDENCIES) -regex '.*\.ml\(i\)*')
-inc_flags:=$(foreach dir,$(DEPENDENCIES),-I $(dir))
+ml_src_files:=$(shell find . -regex '.*\.ml\(i\)*')
+inc_flags:=$(foreach dir,$(shell find . -type d),-I $(dir))
 root_flags:=$(foreach root,$(roots),-r $(root))
 cluster_flags:=$(foreach cluster,$(clusters),-c $(cluster))
 
@@ -279,7 +192,7 @@ mod_dep.dot: $(ml_src_files)
 	$(MAKE) -C $(DEPENDENCIES_DIR)/ocamldot
 	ocamldep.opt $(inc_flags) $(ml_src_files) \
 	| $(DEPENDENCIES_DIR)/ocamldot/ocamldot $(cluster_flags) $(root_flags) \
-	| grep -v -e "\"IList\"\|\"Utils\"" \
+	| grep -v -e "\"IList\"\|\"Utils\"\|\"IStd\"\|\"Infertop\"" \
         > mod_dep.dot
 
 mod_dep.pdf: mod_dep.dot
@@ -289,47 +202,19 @@ mod_dep.pdf: mod_dep.dot
 dsort:
 	$(QUIET)ocamldep.opt -sort $(inc_flags) $(ml_src_files)
 
-define to_ocaml_module
-$(shell \
-  echo $(basename $(1)) \
-  | awk 'BEGIN { FS = "/"; OFS = "/" } ; {$$NF=toupper(substr($$NF,1,1))substr($$NF,2); print $$0}')
-endef
-
-toplevel.mlpack: $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
-#	We need to pack all the infer modules into another module to avoid name clashes with some
-#	of them coming from ocaml libraries (Ident for example).  To do that, we generate a .mlpack
-#	file containing namespaced modules.
-#	1. we filter out roots because they execute code upon loading
-#	2. each source file is converted to a module by capitalizing its first letter
-#	3. we `echo` each module individually to avoid too long a command line
-#	4. prevent race conditions by using a temp file
-	$(eval $@_tmp := $(shell mktemp $@.tmp.XXXX))
-	$(foreach module,\
-	  $(filter-out $(foreach root,$(roots),%/$(root)),\
-	  $(foreach source,\
-	    $(filter-out unit/%,$(OCAML_CONFIG_SOURCES)),\
-	    $(call to_ocaml_module,$(source)))),\
-	  $(shell echo $(module) >> $($@_tmp)))
-	mv $($@_tmp) $@
-
-$(INFER_BUILD_DIR)/toplevel.cmo: toplevel.mlpack
-	$(MKDIR_P) $(BASE_BUILD_DIR)
-	$(OCAMLBUILD_CONFIG) -build-dir $(INFER_BUILD_DIR) toplevel.cmo
+$(INFER_BUILD_DIR)/infertop.bc: $(SRC_DIR)/infertop.ml $(SRC_BUILD_COMMON) $(MAKEFILE_LIST)
+	jbuilder build $@
 	$(QUIET)touch $@
 
 .PHONY: toplevel
-toplevel: $(INFER_BUILD_DIR)/toplevel.cmo
+toplevel: $(INFER_BUILD_DIR)/infertop.bc
 
 .PHONY: checkCopyright
 checkCopyright: $(CHECKCOPYRIGHT_BIN)
 
-$(CHECKCOPYRIGHT_BIN): $(CHECKCOPYRIGHT_MAIN).ml $(MAKEFILE_LIST)
-	$(MKDIR_P) $(BASE_BUILD_DIR)
-	$(OCAMLBUILD) -quiet -r -j $(NCPU) -build-dir $(BASE_BUILD_DIR)/checkCopyright \
-	  -cflags -g,-safe-string -lflags -g \
-	  -pkgs core,str -tag thread -use-ocamlfind $(CHECKCOPYRIGHT_MAIN).native
-	$(INSTALL_PROGRAM) \
-	  $(BASE_BUILD_DIR)/checkCopyright/$(CHECKCOPYRIGHT_MAIN).native $(CHECKCOPYRIGHT_BIN)
+$(CHECKCOPYRIGHT_BIN): scripts/$(CHECKCOPYRIGHT_MAIN).ml $(MAKEFILE_LIST)
+	jbuilder build $(INFER_BUILD_DIR)/scripts/$(CHECKCOPYRIGHT_MAIN).exe
+	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/scripts/$(CHECKCOPYRIGHT_MAIN).exe $(CHECKCOPYRIGHT_BIN)
 
 define gen_atdgen_rules
 # generate files using atdgen
@@ -376,24 +261,30 @@ $(CLANG_BINIOU_DICT): $(CLANG_ATDGEN_STUB_ATD)
 	  | sort | uniq  \
 	  > $@
 
-base/Version.ml: base/Version.ml.in $(MAKEFILE_LIST)
+jbuild jbuild-workspace base/Version.ml: $(MAKEFILE_LIST)
 	TMPFILE=$$(mktemp $@.tmp.XXXX); \
 	INFER_GIT_COMMIT=$$(git --work-tree=$(ROOT_DIR) --git-dir=$(ROOT_DIR)/.git rev-parse --short HEAD || printf "unknown"); \
 	INFER_GIT_BRANCH=$$(git --work-tree=$(ROOT_DIR) --git-dir=$(ROOT_DIR)/.git rev-parse --abbrev-ref HEAD || printf "unknown"); \
 	sed \
+	  -e 's|@EXTRA_CFLAGS[@]|$(EXTRA_CFLAGS)|g' \
 	  -e 's|@INFER_MAJOR[@]|$(INFER_MAJOR)|g' \
 	  -e 's|@INFER_MINOR[@]|$(INFER_MINOR)|g' \
 	  -e 's|@INFER_PATCH[@]|$(INFER_PATCH)|g' \
+	  -e 's|@IS_FACEBOOK_TREE[@]|$(IS_FACEBOOK_TREE)|g' \
 	  -e 's|@IS_RELEASE_TREE[@]|$(IS_RELEASE_TREE)|g' \
 	  -e "s|@INFER_GIT_COMMIT[@]|$$INFER_GIT_COMMIT|g" \
 	  -e "s|@INFER_GIT_BRANCH[@]|$$INFER_GIT_BRANCH|g" \
 	  -e "s|@BUILD_C_ANALYZERS[@]|$(BUILD_C_ANALYZERS)|g" \
 	  -e "s|@BUILD_JAVA_ANALYZERS[@]|$(BUILD_JAVA_ANALYZERS)|g" \
+	  -e "s|@OPAMSWITCH[@]|$(OPAMSWITCH)|g" \
 	  -e "s|@XCODE_SELECT[@]|$(XCODE_SELECT)|g" \
 	  -e "s|@INFER_MAN_LAST_MODIFIED[@]|$(INFER_MAN_LAST_MODIFIED)|g" \
-	  $< > "$$TMPFILE"; \
+	  $@.in > "$$TMPFILE"; \
 	cat "$$TMPFILE" > $@; \
 	$(REMOVE) "$$TMPFILE"
+jbuild: jbuild.in
+jbuild-workspace: jbuild-workspace.in
+base/Version.ml: base/Version.ml.in
 
 .PHONY: clean
 clean:
@@ -401,13 +292,13 @@ clean:
 	$(REMOVE) toplevel.mlpack
 	$(REMOVE_DIR) $(BUILD_DIR)
 	$(REMOVE) $(ETC_DIR)/clang_ast.dict
-	$(REMOVE) base/Version.ml
-	$(REMOVE) base/Version.ml.tmp.*
+	$(REMOVE) base/Version.ml jbuild jbuild-workspace
+	$(REMOVE) base/Version.ml.tmp.* jbuild.tmp.* jbuild-workspace.tmp.*
 	$(REMOVE) backend/jsonbug_{j,t}.ml{,i}
 	$(REMOVE) checkers/stacktree_{j,t}.ml{,i}
 #	be a bit more aggressive than needed with what we remove here so that stale binaries that
 #	only existed in previous versions get removed as well
-	$(REMOVE) $(BIN_DIR)/Infer* $(BIN_DIR)/infer-* $(INFER_BIN){,.byte,.native} $(INFER_BIN_ALIASES) \
+	$(REMOVE) $(BIN_DIR)/Infer* $(BIN_DIR)/infer-* $(INFER_BIN){,.bc,.exe} $(INFER_BIN_ALIASES) \
 	  $(INFERUNIT_BIN) $(CHECKCOPYRIGHT_BIN)
 	$(REMOVE) $(INFER_CREATE_TRACEVIEW_LINKS_BIN)
 	$(REMOVE) $(CLANG_PLUGIN_MIRROR)/*
diff --git a/infer/src/README.md b/infer/src/README.md
new file mode 100644
index 00000000000..4c15e27fff4
--- /dev/null
+++ b/infer/src/README.md
@@ -0,0 +1,8 @@
+The OCaml source files for infer live here. The Makefile is
+responsible for building them, together with jbuild.in.
+
+If you make changes to the build process, also update .merlin
+accordingly. For instance, if you want to add a new source directory
+you will need to:
+- add it to jbuild.in
+- add it to .merlin
diff --git a/infer/src/eradicate/modelTables.ml b/infer/src/eradicate/modelTables.ml
index dc473519282..35d21e0df80 100644
--- a/infer/src/eradicate/modelTables.ml
+++ b/infer/src/eradicate/modelTables.ml
@@ -418,7 +418,7 @@ let mk_table list =
   List.iter ~f:(function v, pn_id -> Hashtbl.replace map pn_id v) list ;
   map
 
-let this_file = __FILE__
+let this_file = Filename.basename __FILE__
 
 let annotated_table_nullable = mk_table annotated_list_nullable
 
diff --git a/infer/src/infertop.ml b/infer/src/infertop.ml
new file mode 100644
index 00000000000..99491e89f56
--- /dev/null
+++ b/infer/src/infertop.ml
@@ -0,0 +1,9 @@
+(*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+;; UTop_main.main ()
diff --git a/infer/src/jbuild-workspace.in b/infer/src/jbuild-workspace.in
new file mode 100644
index 00000000000..bb5c3ebfa71
--- /dev/null
+++ b/infer/src/jbuild-workspace.in
@@ -0,0 +1,9 @@
+;; Do not let jbuilder generate .merlin files because it gets it
+;; wrong. This is mainly due to the fact that source files live in
+;; sub-directories and are copied into _build/ by our jbuild. jbuilder
+;; wants to write "S ." in .merlin but that makes merlin use the
+;; copied source files in _build/ instead of only using the original
+;; files.
+
+(context ((switch @OPAMSWITCH@) (name default)))
+(context ((switch @OPAMSWITCH@) (name test)))
diff --git a/infer/src/jbuild.in b/infer/src/jbuild.in
new file mode 100644
index 00000000000..9495e18f22d
--- /dev/null
+++ b/infer/src/jbuild.in
@@ -0,0 +1,209 @@
+(* -*- tuareg -*- *)
+(* use strings so that it looks like OCaml even before substituting, e.g. to use ocamlformat *)
+
+let is_yes = String.equal "yes"
+
+let clang = is_yes "@BUILD_C_ANALYZERS@"
+
+let java = is_yes "@BUILD_JAVA_ANALYZERS@"
+
+let facebook = is_yes "@IS_FACEBOOK_TREE@"
+
+let extra_cflags = if "@EXTRA_CFLAGS" = "" then [] else ["@EXTRA_CFLAGS@"]
+
+let ( ^/ ) = Filename.concat
+
+(* Compute the list of all the source files.
+
+   This is needed until jbuilder supports finding sources in subdirectories somehow
+   (https://github.com/janestreet/jbuilder/issues/34). *)
+
+let sources =
+  let src_dirs =
+    let src_dir = "." in
+    (* if you update the list of source directories, do not forget to also update .merlin *)
+    src_dir
+    :: ( if facebook then
+           (* do not use the symlinks in src/facebook/: jbuilder will not detect that the files have changed if they are hidden behind a symlink *)
+           "../../facebook/skel/infer/src/facebook"
+       else src_dir ^/ "opensource" )
+       :: List.map (Filename.concat src_dir)
+            ( ( if clang then ["clang"; "clang_plugin"; ("unit" ^/ "clang")]
+              else ["clang_stubs"; ("unit" ^/ "clang_stubs")] )
+            @ [ (if java then "java" else "java_stubs")
+              ; "absint"
+              ; "backend"
+              ; "base"
+              ; "bufferoverrun"
+              ; "checkers"
+              ; "eradicate"
+              ; "harness"
+              ; "integration"
+              ; "IR"
+              ; "labs"
+              ; "quandary"
+              ; "unit" ] )
+  in
+  let files = ref [] in
+  let ml_suffixes = [".ml"; ".mli"; ".mll"; ".mly"] in
+  let add_file dir file =
+    if List.exists (Filename.check_suffix file) ml_suffixes then files := (dir ^/ file) :: !files
+  in
+  let one_dir dir =
+    (* absolute path so that running jbuilder from any subdirectory (in particular from src/Makefile)
+       points at the right original files in ocamlc's error messages *)
+    let abs_dir = Sys.getcwd () ^/ dir in
+    Array.iter (add_file abs_dir) (Sys.readdir dir)
+  in
+  List.iter one_dir src_dirs ; !files
+
+let common_cflags =
+  let fatal_warnings = "+3+5+6+8+10+11+12+18+19+20+21+23+26+29+27+33+34+35+37+38+39+50+52+57" in
+  let warnings = fatal_warnings ^ "-4-9-32-40-41-42-45-48" in
+  let common_flags =
+    [ "-g"
+    ; "-short-paths"
+    ; "-safe-string"
+    ; "-principal"
+    ; "-strict-formats"
+    ; "-strict-sequence"
+    ; "-bin-annot"
+    ; "-w"
+    ; warnings ]
+  in
+  match Jbuild_plugin.V1.context with
+  | "test"
+   -> "-warn-error" :: fatal_warnings :: common_flags
+  | "default"
+   -> common_flags
+  | ctx
+   -> invalid_arg ("unknown context: " ^ ctx)
+
+(** Make a library that includes just IStd and IList. These files have different compilation flags
+    than infer (they don't include IStd!). *)
+let inferBaseStdlib = "InferBaseStdlib"
+
+let iStd = "IStd"
+
+let inferBaseStdlib_modules = ["IList"; iStd]
+
+let inferBaseStdlib_cflags = common_cflags
+
+(** Generated code (eg, from atdgen) is also compiled using different flags, so pack it in a
+    separated library. *)
+let inferGenerated = "InferGenerated"
+
+let inferGenerated_modules =
+  ( if clang then
+      [ "Clang_ast_b"
+      ; "Clang_ast_j"
+      ; "Clang_ast_t"
+      ; "Clang_ast_v"
+      ; "Clang_ast_proj"
+      ; "Clang_ast_types"
+      ; "Clang_ast_visit" ]
+  else [] )
+  @ ["Jsonbug_j"; "Jsonbug_t"; "Stacktree_j"; "Stacktree_t"]
+
+let inferGenerated_cflags = common_cflags @ ["-w"; "-27-32-34-35-39"]
+
+let infer_binaries =
+  ["infer"; "inferunit"] @ if facebook then ["InferCreateTraceViewLinks"] else []
+
+let infer_cflags =
+  common_cflags @ ["-open"; inferBaseStdlib; "-open"; iStd; "-open"; inferGenerated]
+
+let common_libraries =
+  (if java then ["javalib"; "ptrees"; "sawja"] else [])
+  @ [ "ANSITerminal"
+    ; "atdgen"
+    ; "cmdliner"
+    ; "core"
+    ; "extlib"
+    ; "oUnit"
+    ; "parmap"
+    ; "str"
+    ; "unix"
+    ; "xmlm"
+    ; "yojson"
+    ; "zip" ]
+
+(** Return the best copy action for a given [source] file. That is, when possibly, use "copy#" so
+    that jump-to-defition and compiler errors go to the right original source file, otherwise do a
+    normal copy. *)
+let copy_action_of_source source =
+  if Filename.check_suffix source ".mly" then
+    (* menhir doesn't support '# 1 "<source file>"' directives at the start of the file inserted by
+       copy# actions *)
+    "copy"
+  else "copy#"
+
+(** The build stanzas to be passed to jbuilder *)
+let stanzas =
+  ( if clang then
+      ["(ocamllex (types_lexer ctl_lexer))"; "(menhir ((modules (types_parser ctl_parser))))"]
+  else [] )
+  @ [ Format.sprintf
+        {|
+(library
+ ((name %s)
+  (flags (%s))
+  (modules (%s))
+  (libraries (atdgen))
+ ))
+|}
+        inferGenerated (String.concat " " inferGenerated_cflags)
+        (String.concat " " inferGenerated_modules)
+    ; Format.sprintf
+        {|
+(library
+ ((name %s)
+  (flags (%s))
+  (modules (%s))
+  (libraries (%s))
+ ))
+|}
+        inferBaseStdlib (String.concat " " inferBaseStdlib_cflags)
+        (String.concat " " inferBaseStdlib_modules) (String.concat " " common_libraries)
+    ; Format.sprintf
+        {|
+(library
+ ((name InferModules)
+  (flags (%s))
+  (libraries (%s %s %s))
+  (modules (:standard \ %s infertop %s %s))
+  (preprocess (pps (ppx_compare)))
+ ))
+|}
+        (String.concat " " infer_cflags) (String.concat " " common_libraries) inferBaseStdlib
+        inferGenerated (String.concat " " infer_binaries)
+        (String.concat " " inferBaseStdlib_modules) (String.concat " " inferGenerated_modules)
+    ; Format.sprintf
+        {|
+(executables
+ ((names (%s))
+  (flags (%s -open InferModules))
+  (libraries (InferModules))
+  (modules (%s))
+  (preprocess (pps (ppx_compare)))
+ ))
+|}
+        (String.concat " " infer_binaries) (String.concat " " infer_cflags)
+        (String.concat " " infer_binaries)
+    ; Format.sprintf
+        {|
+(executable
+ ((name infertop)
+  (flags (%s))
+  (libraries (utop InferModules))
+  (modules (:standard \ %s))
+  (link_flags (-linkall -warn-error -31))))
+|}
+        (String.concat " " infer_cflags) (String.concat " " infer_binaries) ]
+  @ List.map
+      (fun source ->
+        Printf.sprintf "(rule (%s %s %s))" (copy_action_of_source source) source
+          (Filename.basename source))
+      sources
+
+;; String.concat "\n" stanzas |> Jbuild_plugin.V1.send
diff --git a/infer/src/scripts/checkCopyright.ml b/infer/src/scripts/checkCopyright.ml
index 76687c0cd78..62cba5dce33 100644
--- a/infer/src/scripts/checkCopyright.ml
+++ b/infer/src/scripts/checkCopyright.ml
@@ -7,7 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *)
 
-open! Core.Std
+open! Core
 module F = Format
 
 let copyright_modified_exit_code = 1
@@ -193,7 +193,7 @@ let copyright_has_changed mono fb_year com_style prefix cstart cend lines_arr =
 
 let update_file fname mono fb_year com_style prefix cstart cend lines_arr =
   try
-    let cout = open_out fname in
+    let cout = Out_channel.create fname in
     let fmt = F.formatter_of_out_channel cout in
     for i = 0 to cstart - 1 do F.fprintf fmt "%s@." lines_arr.(i) done ;
     pp_copyright mono fb_year com_style fmt prefix ;
diff --git a/infer/src/scripts/jbuild b/infer/src/scripts/jbuild
new file mode 100644
index 00000000000..b6de5ab89ee
--- /dev/null
+++ b/infer/src/scripts/jbuild
@@ -0,0 +1,7 @@
+(jbuild_version 1)
+
+(executable
+ ((name checkCopyright)
+  (flags (:standard -g -short-paths -safe-string -principal -strict-formats -strict-sequence -bin-annot -w +3+5+6+8+10+11+12+18+19+20+21+23+26+29+27+33+34+35+37+38+39+50+52+57-4-9-32-40-41-42-45-48))
+  (libraries (core str))
+ ))
diff --git a/infer/tests/build_systems/buck_flavors_deterministic/Makefile b/infer/tests/build_systems/buck_flavors_deterministic/Makefile
index 93dfdb302d4..c6b291e42e6 100644
--- a/infer/tests/build_systems/buck_flavors_deterministic/Makefile
+++ b/infer/tests/build_systems/buck_flavors_deterministic/Makefile
@@ -45,6 +45,9 @@ differences.exp.test: $(CLANG_DEPS) $(SOURCES) $(MAKEFILE_LIST)
 	)
 	$(QUIET)$(REMOVE) capture_hash-1.sha capture_hash-2.sha
 
+.PHONY: print
+print: differences.exp.test
+
 .PHONY: test
 test: differences.exp.test
 	$(QUIET)diff -u differences.exp $<
diff --git a/infer/tests/build_systems/infertop/Makefile b/infer/tests/build_systems/infertop/Makefile
new file mode 100644
index 00000000000..f52aaa8f85c
--- /dev/null
+++ b/infer/tests/build_systems/infertop/Makefile
@@ -0,0 +1,31 @@
+# Copyright (c) 2017 - present Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+TESTS_DIR = ../..
+ROOT_DIR = $(TESTS_DIR)/../..
+
+include $(TESTS_DIR)/base.make
+
+toplevel.exp.test: $(BUILD_DIR)/test/infertop.bc
+	$(QUIET)$(call silent_on_success,Testing infer OCaml REPL,\
+	TOPLEVEL_DIR=$(BUILD_DIR)/test $(SCRIPT_DIR)/infer_repl \
+	  $(INFER_DIR)/tests/repl/infer_batch_script.mltop > $@)
+
+.PHONY: print
+print: toplevel.exp.test
+
+.PHONY: test
+test: toplevel.exp.test
+	$(QUIET)diff -u toplevel.exp $<
+
+.PHONY: replace
+replace: toplevel.exp.test
+	$(QUIET)$(COPY) $< toplevel.exp
+
+.PHONY: clean
+clean:
+	$(QUIET)$(REMOVE) toplevel.exp.test
diff --git a/infer/tests/build_systems/infertop/toplevel.exp b/infer/tests/build_systems/infertop/toplevel.exp
new file mode 100644
index 00000000000..5272fa1cc09
--- /dev/null
+++ b/infer/tests/build_systems/infertop/toplevel.exp
@@ -0,0 +1,11 @@
+Findlib has been successfully loaded. Additional directives:
+  #require "package";;      to load a package
+  #list;;                   to list the available packages
+  #camlp4o;;                to load camlp4 (standard syntax)
+  #camlp4r;;                to load camlp4 (revised syntax)
+  #predicates "p,q,...";;   to set these predicates
+  Topfind.reset();;         to force that packages will be reloaded
+  #thread;;                 to enable threads
+
+n$2
+false
diff --git a/infer/tests/codetoanalyze/java/eradicate/issues.exp b/infer/tests/codetoanalyze/java/eradicate/issues.exp
index c5b294efec0..811cd53a5b9 100644
--- a/infer/tests/codetoanalyze/java/eradicate/issues.exp
+++ b/infer/tests/codetoanalyze/java/eradicate/issues.exp
@@ -27,11 +27,11 @@ codetoanalyze/java/eradicate/InconsistentSubclassAnnotation.java, String Inconsi
 codetoanalyze/java/eradicate/InconsistentSubclassAnnotation.java, SubclassExample$T SubclassExample$B.foo(), 0, ERADICATE_INCONSISTENT_SUBCLASS_RETURN_ANNOTATION, [Method `SubclassExample$B.foo()` is annotated with `@Nullable` but overrides unannotated method `SubclassExample$A.foo()`.]
 codetoanalyze/java/eradicate/InconsistentSubclassAnnotation.java, SubclassExample$T SubclassExample$C.baz(), 0, ERADICATE_INCONSISTENT_SUBCLASS_RETURN_ANNOTATION, [Method `SubclassExample$C.baz()` is annotated with `@Nullable` but overrides unannotated method `SubclassExample$I.baz()`.]
 codetoanalyze/java/eradicate/InconsistentSubclassAnnotation.java, void SubclassExample$D.deref(SubclassExample$T), 0, ERADICATE_INCONSISTENT_SUBCLASS_PARAMETER_ANNOTATION, [First parameter `t` of method `SubclassExample$D.deref(...)` is not `@Nullable` but is declared `@Nullable`in the parent class method `SubclassExample$A.deref(...)`.]
-codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badAtomicReferenceDereference(AtomicReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in eradicate/modelTables.ml at line 37)]
-codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badPhantomReferenceDereference(PhantomReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in eradicate/modelTables.ml at line 29)]
-codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badReferenceDereference(Reference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in eradicate/modelTables.ml at line 21)]
-codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badSoftReferenceDereference(SoftReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in eradicate/modelTables.ml at line 33)]
-codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badWeakReferenceDereference(WeakReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in eradicate/modelTables.ml at line 25)]
+codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badAtomicReferenceDereference(AtomicReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in modelTables.ml at line 37)]
+codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badPhantomReferenceDereference(PhantomReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in modelTables.ml at line 29)]
+codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badReferenceDereference(Reference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in modelTables.ml at line 21)]
+codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badSoftReferenceDereference(SoftReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in modelTables.ml at line 33)]
+codetoanalyze/java/eradicate/LibraryCalls.java, String LibraryCalls.badWeakReferenceDereference(WeakReference), 1, ERADICATE_NULL_METHOD_CALL, [origin,The value of `ref.get()` in the call to `toString()` could be null. (Origin: call to get() modelled in modelTables.ml at line 25)]
 codetoanalyze/java/eradicate/NullFieldAccess.java, Object NullFieldAccess.arrayAccess(), 1, ERADICATE_NULL_FIELD_ACCESS, [origin,Object `NullFieldAccess.objects` could be null when accessing element at index `0`. (Origin: field NullFieldAccess.objects at line 63)]
 codetoanalyze/java/eradicate/NullFieldAccess.java, int NullFieldAccess.arrayLength(), 1, ERADICATE_NULL_FIELD_ACCESS, [origin,Object `NullFieldAccess.objects` could be null when accessing field `length`. (Origin: field NullFieldAccess.objects at line 59)]
 codetoanalyze/java/eradicate/NullFieldAccess.java, int NullFieldAccess.useInterface(NullFieldAccess$I), 2, ERADICATE_NULL_FIELD_ACCESS, [origin,Object `c` could be null when accessing field `NullFieldAccess$C.n`. (Origin: field NullFieldAccess$I.c at line 52)]
@@ -39,11 +39,11 @@ codetoanalyze/java/eradicate/NullFieldAccess.java, int NullFieldAccess.useX(), 2
 codetoanalyze/java/eradicate/NullFieldAccess.java, int NullFieldAccess.useZ(), 2, ERADICATE_NULL_FIELD_ACCESS, [origin,Object `c` could be null when accessing field `NullFieldAccess$C.n`. (Origin: field NullFieldAccess.z at line 47)]
 codetoanalyze/java/eradicate/NullMethodCall.java, int NullMethodCall$Inner.outerField(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: field NullMethodCall.fld at line 71)]
 codetoanalyze/java/eradicate/NullMethodCall.java, int NullMethodCall$Inner.outerPrivateField(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: field NullMethodCall.pfld at line 82)]
-codetoanalyze/java/eradicate/NullMethodCall.java, int NullMethodCall.testSystemGetenvBad(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `envValue` in the call to `length()` could be null. (Origin: call to getenv(...) modelled in eradicate/modelTables.ml at line 243)]
+codetoanalyze/java/eradicate/NullMethodCall.java, int NullMethodCall.testSystemGetenvBad(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `envValue` in the call to `length()` could be null. (Origin: call to getenv(...) modelled in modelTables.ml at line 243)]
 codetoanalyze/java/eradicate/NullMethodCall.java, void NullMethodCall.callOnNull(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: null constant at line 22)]
 codetoanalyze/java/eradicate/NullMethodCall.java, void NullMethodCall.testExceptionPerInstruction(int), 6, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: null constant at line 183)]
 codetoanalyze/java/eradicate/NullMethodCall.java, void NullMethodCall.testFieldAssignmentIfThenElse(String), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: null constant at line 174)]
-codetoanalyze/java/eradicate/NullMethodCall.java, void NullMethodCall.testSystemGetPropertyReturn(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: call to getProperty(...) modelled in eradicate/modelTables.ml at line 238)]
+codetoanalyze/java/eradicate/NullMethodCall.java, void NullMethodCall.testSystemGetPropertyReturn(), 2, ERADICATE_NULL_METHOD_CALL, [origin,The value of `s` in the call to `length()` could be null. (Origin: call to getProperty(...) modelled in modelTables.ml at line 238)]
 codetoanalyze/java/eradicate/ParameterNotNullable.java, ParameterNotNullable$ConstructorCall.<init>(ParameterNotNullable,int), 1, ERADICATE_PARAMETER_NOT_NULLABLE, [origin,`ParameterNotNullable$ConstructorCall(...)` needs a non-null value in parameter 2 but argument `null` can be null. (Origin: null constant at line 102)]
 codetoanalyze/java/eradicate/ParameterNotNullable.java, String ParameterNotNullable.testSystemGetPropertyArgument(), 1, ERADICATE_PARAMETER_NOT_NULLABLE, [origin,`getProperty(...)` needs a non-null value in parameter 1 but argument `null` can be null. (Origin: null constant at line 71)]
 codetoanalyze/java/eradicate/ParameterNotNullable.java, String ParameterNotNullable.testSystemGetenvBad(), 1, ERADICATE_PARAMETER_NOT_NULLABLE, [origin,`getenv(...)` needs a non-null value in parameter 1 but argument `null` can be null. (Origin: null constant at line 76)]
@@ -67,4 +67,4 @@ codetoanalyze/java/eradicate/ReturnNotNullable.java, String ReturnNotNullable.re
 codetoanalyze/java/eradicate/ReturnNotNullable.java, String ReturnNotNullable.returnNullable(String), 0, ERADICATE_RETURN_NOT_NULLABLE, [Method `returnNullable(...)` may return null but it is not annotated with `@Nullable`. (Origin: method parameter s)]
 codetoanalyze/java/eradicate/ReturnNotNullable.java, String ReturnNotNullable.return_null_in_catch(), 0, ERADICATE_RETURN_NOT_NULLABLE, [origin,Method `return_null_in_catch()` may return null but it is not annotated with `@Nullable`. (Origin: null constant at line 111)]
 codetoanalyze/java/eradicate/ReturnNotNullable.java, String ReturnNotNullable.return_null_in_catch_after_throw(), 0, ERADICATE_RETURN_NOT_NULLABLE, [origin,Method `return_null_in_catch_after_throw()` may return null but it is not annotated with `@Nullable`. (Origin: null constant at line 123)]
-codetoanalyze/java/eradicate/ReturnNotNullable.java, URL ReturnNotNullable.getResourceNullable(Class,String), 0, ERADICATE_RETURN_NOT_NULLABLE, [origin,Method `getResourceNullable(...)` may return null but it is not annotated with `@Nullable`. (Origin: call to getResource(...) modelled in eradicate/modelTables.ml at line 128)]
+codetoanalyze/java/eradicate/ReturnNotNullable.java, URL ReturnNotNullable.getResourceNullable(Class,String), 0, ERADICATE_RETURN_NOT_NULLABLE, [origin,Method `getResourceNullable(...)` may return null but it is not annotated with `@Nullable`. (Origin: call to getResource(...) modelled in modelTables.ml at line 128)]
diff --git a/opam b/opam
index 9a042c39787..fe3513645fe 100644
--- a/opam
+++ b/opam
@@ -34,6 +34,7 @@ depends: [
   "ctypes" {>="0.9.2"}
   "extlib-compat"
   "javalib" {>="2.3.3"}
+  "jbuilder" {build & >="1.0+beta11"}
   "ocamlfind" {build}
   "ounit" {="2.0.0"}
   "parmap" {>="1.0-rc8"}
diff --git a/scripts/infer_repl b/scripts/infer_repl
index 87cc921e2a9..654adc512d0 100755
--- a/scripts/infer_repl
+++ b/scripts/infer_repl
@@ -1,20 +1,25 @@
 #!/bin/bash
 
-SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+## Wrapper around infertop. To build infertop, run `make toplevel`.
 
-# where to find toplevel.cmo, can be overridden
-TOPLEVEL_DIR=${TOPLEVEL_DIR:-"$SCRIPT_DIR"/../infer/_build/infer}
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-# how to load the toplevel; can be overridden (with "ocaml" for example)
-INFER_REPL_BINARY=${INFER_REPL_BINARY:-"utop"}
+# where to find toplevel.bc, can be overridden
+TOPLEVEL_DIR=${TOPLEVEL_DIR:-"$SCRIPT_DIR"/../infer/src/_build/default}
 
-# to build new toplevel, run `make toplevel`
-# -init option is used only in interactive mode
-# in batch mode, scripts need to import toplevel_init themselves
+# The -init option is effective only in interactive mode.
+# In batch mode, scripts need to import toplevel_init themselves.
 # It can be done by adding #use "toplevel_init";; to the beginning
 # of a script.
 # NOTE: $SCRIPT_DIR is added search path for batch scripts
 #       so they can be located anywhere and still find toplevel_init
 #       file. In interactive mode $SCRIPT_DIR isn't needed
 
-"$INFER_REPL_BINARY" -init "$SCRIPT_DIR"/toplevel_init -I "$TOPLEVEL_DIR" -I "$SCRIPT_DIR" $@
+set -x
+# infertop expects to be run from where jbuild is located
+cd "$SCRIPT_DIR"/../infer
+"$TOPLEVEL_DIR"/infertop.bc \
+  -init "$SCRIPT_DIR"/toplevel_init \
+  -I "$TOPLEVEL_DIR" \
+  -I "$SCRIPT_DIR" \
+  "$@"
diff --git a/scripts/toplevel_init b/scripts/toplevel_init
index ff5a83ec36a..ddaad8650c7 100644
--- a/scripts/toplevel_init
+++ b/scripts/toplevel_init
@@ -1,3 +1,5 @@
+(* to be used with infertop, infer's custom toplevel *)
+
 (* load dependencies *)
 #use "topfind";;
 #thread;;
@@ -10,6 +12,5 @@
 #require "xmlm";;
 #require "ANSITerminal";;
 
-(* load infer code *)
-#load_rec "toplevel.cmo";;
-open Toplevel;;
+open InferModules;;
+open InferBaseStdlib;;