Auto merge of #27630 - sylvestre:master, r=dotdash

[rust.git] / mk / platform.mk

diff --git a/mk/platform.mk b/mk/platform.mk
index 8a5e58c46f676ef726b59410fe7d321700301327..9a6de772ab4a84a59d0f6f6b211e00b6dde6b660 100644 (file)
--- a/mk/platform.mk
+++ b/mk/platform.mk
@@ -113,8 +113,7 @@ CFG_RLIB_GLOB=lib$(1)-*.rlib
 include $(wildcard $(CFG_SRC_DIR)mk/cfg/*.mk)
 
 define ADD_INSTALLED_OBJECTS
-  INSTALLED_OBJECTS_$(1) += $$(call CFG_STATIC_LIB_NAME_$(1),morestack) \
-                            $$(call CFG_STATIC_LIB_NAME_$(1),compiler-rt)
+  INSTALLED_OBJECTS_$(1) += $$(call CFG_STATIC_LIB_NAME_$(1),compiler-rt)
 endef
 
 $(foreach target,$(CFG_TARGET), \
@@ -238,3 +237,64 @@ endef
 
 $(foreach target,$(CFG_TARGET), \
   $(eval $(call CFG_MAKE_TOOLCHAIN,$(target))))
+
+# There are more comments about this available in the target specification for
+# Windows MSVC in the compiler, but the gist of it is that we use `llvm-ar.exe`
+# instead of `lib.exe` for assembling archives, so we need to inject this custom
+# dependency here.
+#
+# FIXME(stage0): remove this and all other relevant support in the makefiles
+#                after a snapshot is made
+define ADD_LLVM_AR_TO_MSVC_DEPS
+ifeq ($$(findstring msvc,$(1)),msvc)
+NATIVE_TOOL_DEPS_core_T_$(1) += llvm-ar.exe
+INSTALLED_BINS_$(1) += llvm-ar.exe
+endif
+endef
+
+$(foreach target,$(CFG_TARGET), \
+  $(eval $(call ADD_LLVM_AR_TO_MSVC_DEPS,$(target))))
+
+# When working with MSVC on windows, each DLL needs to explicitly declare its
+# interface to the outside world through some means. The options for doing so
+# include:
+#
+# 1. A custom attribute on each function itself
+# 2. A linker argument saying what to export
+# 3. A file which lists all symbols that need to be exported
+#
+# The Rust compiler takes care (1) for us for all Rust code by annotating all
+# public-facing functions with dllexport, but we have a few native dependencies
+# which need to cross the DLL boundary. The most important of these dependencies
+# is LLVM which is linked into `rustc_llvm.dll` but primarily used from
+# `rustc_trans.dll`. This means that many of LLVM's C API functions need to be
+# exposed from `rustc_llvm.dll` to be forwarded over the boundary.
+#
+# Unfortunately, at this time, LLVM does not handle this sort of exportation on
+# Windows for us, so we're forced to do it ourselves if we want it (which seems
+# like the path of least resistance right now). To do this we generate a `.DEF`
+# file [1] which we then custom-pass to the linker when building the rustc_llvm
+# crate. This DEF file list all symbols that are exported from
+# `src/librustc_llvm/lib.rs` and is generated by a small python script.
+#
+# Fun times!
+#
+# [1]: https://msdn.microsoft.com/en-us/library/28d6s79h.aspx
+#
+# FIXME(stage0): remove this macro and the usage below (and the commments above)
+#               when a new snapshot is available. Also remove the
+#               RUSTFLAGS$(1)_.._T_ variable in mk/target.mk along with
+#               CUSTOM_DEPS (as they were only added for this)
+define ADD_RUSTC_LLVM_DEF_TO_MSVC
+ifeq ($$(findstring msvc,$(1)),msvc)
+RUSTFLAGS0_rustc_llvm_T_$(1) += -C link-args="-DEF:$(1)/rt/rustc_llvm.def"
+CUSTOM_DEPS0_rustc_llvm_T_$(1) += $(1)/rt/rustc_llvm.def
+
+$(1)/rt/rustc_llvm.def: $$(S)src/etc/mklldef.py $$(S)src/librustc_llvm/lib.rs
+       $$(CFG_PYTHON) $$^ $$@ rustc_llvm-$$(CFG_FILENAME_EXTRA)
+endif
+endef
+
+$(foreach target,$(CFG_TARGET), \
+  $(eval $(call ADD_RUSTC_LLVM_DEF_TO_MSVC,$(target))))
+