std: Add support for Windows XP

configure

@@ -1114,7 +1114,7 @@ do
             fi
             ;;
 
-        x86_64-*-msvc)
+        *-msvc)
             # Currently the build system is not configured to build jemalloc
             # with MSVC, so we omit this optional dependency.
             step_msg "targeting MSVC, disabling jemalloc"
@@ -1154,22 +1154,45 @@ do
             CFG_MSVC_ROOT=$(echo "$install" | grep InstallDir | sed 's/.*REG_SZ[ ]*//')
             CFG_MSVC_ROOT=$(dirname "$CFG_MSVC_ROOT")
             CFG_MSVC_ROOT=$(dirname "$CFG_MSVC_ROOT")
-            CFG_MSVC_CL="${CFG_MSVC_ROOT}/VC/bin/amd64/cl.exe"
-            CFG_MSVC_LIB="${CFG_MSVC_ROOT}/VC/bin/amd64/lib.exe"
-            CFG_MSVC_LINK="${CFG_MSVC_ROOT}/VC/bin/amd64/link.exe"
+            putvar CFG_MSVC_ROOT
+
+            case $i in
+                x86_64-*)
+                    bits=x86_64
+                    msvc_part=amd64
+                    ;;
+                i686-*)
+                    bits=i386
+                    msvc_part=
+                    ;;
+                *)
+                    err "can only target x86 targets for MSVC"
+                    ;;
+            esac
+            bindir="${CFG_MSVC_ROOT}/VC/bin"
+            if [ ! -z "$msvc_part" ]; then
+                bindir="$bindir/$msvc_part"
+            fi
+            eval CFG_MSVC_BINDIR_$bits="\"$bindir\""
+            eval CFG_MSVC_CL_$bits="\"$bindir/cl.exe\""
+            eval CFG_MSVC_LIB_$bits="\"$bindir/lib.exe\""
+            eval CFG_MSVC_LINK_$bits="\"$bindir/link.exe\""
 
             vcvarsall="${CFG_MSVC_ROOT}/VC/vcvarsall.bat"
-            CFG_MSVC_INCLUDE_PATH=$(cmd /c "\"$vcvarsall\" amd64 && cmd /c echo %INCLUDE%")
+            include_path=$(cmd /c "\"$vcvarsall\" $msvc_part && cmd /c echo %INCLUDE%")
             need_ok "failed to learn about MSVC's INCLUDE"
-            CFG_MSVC_LIB_PATH=$(cmd /c "\"$vcvarsall\" amd64 && cmd /c echo %LIB%")
+            lib_path=$(cmd /c "\"$vcvarsall\" $msvc_part && cmd /c echo %LIB%")
             need_ok "failed to learn about MSVC's LIB"
 
-            putvar CFG_MSVC_ROOT
-            putvar CFG_MSVC_CL
-            putvar CFG_MSVC_LIB
-            putvar CFG_MSVC_LINK
-            putvar CFG_MSVC_INCLUDE_PATH
-            putvar CFG_MSVC_LIB_PATH
+            eval CFG_MSVC_INCLUDE_PATH_${bits}="\"$include_path\""
+            eval CFG_MSVC_LIB_PATH_${bits}="\"$lib_path\""
+
+            putvar CFG_MSVC_BINDIR_${bits}
+            putvar CFG_MSVC_CL_${bits}
+            putvar CFG_MSVC_LIB_${bits}
+            putvar CFG_MSVC_LINK_${bits}
+            putvar CFG_MSVC_INCLUDE_PATH_${bits}
+            putvar CFG_MSVC_LIB_PATH_${bits}
             ;;
 
         *)
@@ -1408,8 +1431,19 @@ do
 
         msg "configuring LLVM with:"
         msg "$CMAKE_ARGS"
+        case "$t" in
+            x86_64-*)
+                generator="Visual Studio 12 2013 Win64"
+                ;;
+            i686-*)
+                generator="Visual Studio 12 2013"
+                ;;
+            *)
+                err "can only build LLVM for x86 platforms"
+                ;;
+        esac
         (cd $LLVM_BUILD_DIR && "$CFG_CMAKE" $CFG_LLVM_SRC_DIR \
-                                            -G "Visual Studio 12 2013 Win64" \
+                                            -G "$generator" \
                                             $CMAKE_ARGS)
         need_ok "LLVM cmake configure failed"
     fi

mk/cfg/i686-pc-windows-msvc.mk

@@ -0,0 +1,29 @@
+# i686-pc-windows-msvc configuration
+CC_i686-pc-windows-msvc="$(CFG_MSVC_CL_i386)" -nologo
+LINK_i686-pc-windows-msvc="$(CFG_MSVC_LINK_i386)" -nologo
+CXX_i686-pc-windows-msvc="$(CFG_MSVC_CL_i386)" -nologo
+CPP_i686-pc-windows-msvc="$(CFG_MSVC_CL_i386)" -nologo
+AR_i686-pc-windows-msvc="$(CFG_MSVC_LIB_i386)" -nologo
+CFG_LIB_NAME_i686-pc-windows-msvc=$(1).dll
+CFG_STATIC_LIB_NAME_i686-pc-windows-msvc=$(1).lib
+CFG_LIB_GLOB_i686-pc-windows-msvc=$(1)-*.{dll,lib}
+CFG_LIB_DSYM_GLOB_i686-pc-windows-msvc=$(1)-*.dylib.dSYM
+CFG_JEMALLOC_CFLAGS_i686-pc-windows-msvc :=
+CFG_GCCISH_CFLAGS_i686-pc-windows-msvc := -MD
+CFG_GCCISH_CXXFLAGS_i686-pc-windows-msvc := -MD
+CFG_GCCISH_LINK_FLAGS_i686-pc-windows-msvc :=
+CFG_GCCISH_DEF_FLAG_i686-pc-windows-msvc :=
+CFG_LLC_FLAGS_i686-pc-windows-msvc :=
+CFG_INSTALL_NAME_i686-pc-windows-msvc =
+CFG_EXE_SUFFIX_i686-pc-windows-msvc := .exe
+CFG_WINDOWSY_i686-pc-windows-msvc := 1
+CFG_UNIXY_i686-pc-windows-msvc :=
+CFG_LDPATH_i686-pc-windows-msvc :=
+CFG_RUN_i686-pc-windows-msvc=$(2)
+CFG_RUN_TARG_i686-pc-windows-msvc=$(call CFG_RUN_i686-pc-windows-msvc,,$(2))
+CFG_GNU_TRIPLE_i686-pc-windows-msvc := i686-pc-win32
+
+# All windows nightiles are currently a GNU triple, so this MSVC triple is not
+# bootstrapping from itself. This is relevant during stage0, and other parts of
+# the build system take this into account.
+BOOTSTRAP_FROM_i686-pc-windows-msvc := i686-pc-windows-gnu

mk/cfg/x86_64-pc-windows-msvc.mk

@@ -1,9 +1,9 @@
 # x86_64-pc-windows-msvc configuration
-CC_x86_64-pc-windows-msvc="$(CFG_MSVC_CL)" -nologo
-LINK_x86_64-pc-windows-msvc="$(CFG_MSVC_LINK)" -nologo
-CXX_x86_64-pc-windows-msvc="$(CFG_MSVC_CL)" -nologo
-CPP_x86_64-pc-windows-msvc="$(CFG_MSVC_CL)" -nologo
-AR_x86_64-pc-windows-msvc="$(CFG_MSVC_LIB)" -nologo
+CC_x86_64-pc-windows-msvc="$(CFG_MSVC_CL_x86_64)" -nologo
+LINK_x86_64-pc-windows-msvc="$(CFG_MSVC_LINK_x86_64)" -nologo
+CXX_x86_64-pc-windows-msvc="$(CFG_MSVC_CL_x86_64)" -nologo
+CPP_x86_64-pc-windows-msvc="$(CFG_MSVC_CL_x86_64)" -nologo
+AR_x86_64-pc-windows-msvc="$(CFG_MSVC_LIB_x86_64)" -nologo
 CFG_LIB_NAME_x86_64-pc-windows-msvc=$(1).dll
 CFG_STATIC_LIB_NAME_x86_64-pc-windows-msvc=$(1).lib
 CFG_LIB_GLOB_x86_64-pc-windows-msvc=$(1)-*.{dll,lib}

mk/platform.mk

@@ -239,23 +239,6 @@ endef
 $(foreach target,$(CFG_TARGET), \
   $(eval $(call CFG_MAKE_TOOLCHAIN,$(target))))
 
-# These two environment variables are scraped by the `./configure` script and
-# are necessary for `cl.exe` to find standard headers (the INCLUDE variable) and
-# for `link.exe` to find standard libraries (the LIB variable).
-ifdef CFG_MSVC_INCLUDE_PATH
-export INCLUDE := $(CFG_MSVC_INCLUDE_PATH)
-endif
-ifdef CFG_MSVC_LIB_PATH
-export LIB := $(CFG_MSVC_LIB_PATH)
-endif
-
-# Unfortunately `link.exe` is also a program in `/usr/bin` on MinGW installs,
-# but it's not the one that we want. As a result we make sure that our detected
-# `link.exe` shows up in PATH first.
-ifdef CFG_MSVC_LINK
-export PATH := $(CFG_MSVC_ROOT)/VC/bin/amd64:$(PATH)
-endif
-
 # 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
@@ -307,3 +290,4 @@ endef
 
 $(foreach target,$(CFG_TARGET), \
   $(eval $(call ADD_RUSTC_LLVM_DEF_TO_MSVC,$(target))))
+

mk/rt.mk

@@ -55,7 +55,11 @@ NATIVE_DEPS_rust_builtin_$(1) := rust_builtin.c \
 			rust_android_dummy.c
 NATIVE_DEPS_rustrt_native_$(1) := arch/$$(HOST_$(1))/record_sp.S
 ifeq ($$(findstring msvc,$(1)),msvc)
+ifeq ($$(findstring i686,$(1)),i686)
+NATIVE_DEPS_rustrt_native_$(1) += rust_try_msvc_32.ll
+else
 NATIVE_DEPS_rustrt_native_$(1) += rust_try_msvc_64.ll
+endif
 else
 NATIVE_DEPS_rustrt_native_$(1) += rust_try.ll
 endif
@@ -93,6 +97,17 @@ $$(RT_OUTPUT_DIR_$(1))/%.o: $(S)src/rt/%.S $$(MKFILE_DEPS) \
 	@mkdir -p $$(@D)
 	@$$(call E, compile: $$@)
 	$$(Q)$$(call CFG_ASSEMBLE_$(1),$$@,$$<)
+
+# On MSVC targets the compiler's default include path (e.g. where to find system
+# headers) is specified by the INCLUDE environment variable. This may not be set
+# so the ./configure script scraped the relevant values and this is the location
+# that we put them into cl.exe's environment.
+ifeq ($$(findstring msvc,$(1)),msvc)
+$$(RT_OUTPUT_DIR_$(1))/%.o: \
+	export INCLUDE := $$(CFG_MSVC_INCLUDE_PATH_$$(HOST_$(1)))
+$(1)/rustllvm/%.o: \
+	export INCLUDE := $$(CFG_MSVC_INCLUDE_PATH_$$(HOST_$(1)))
+endif
 endef
 
 $(foreach target,$(CFG_TARGET),$(eval $(call NATIVE_LIBRARIES,$(target))))
@@ -240,8 +255,12 @@ COMPRT_CFLAGS_$(1) := $$(CFG_GCCISH_CFLAGS_$(1))
 ifeq ($$(findstring msvc,$(1)),msvc)
 COMPRT_CC_$(1) := gcc
 COMPRT_AR_$(1) := ar
+ifeq ($$(findstring i686,$(1)),i686)
+COMPRT_CFLAGS_$(1) := $$(CFG_GCCISH_CFLAGS_$(1)) -m32
+else
 COMPRT_CFLAGS_$(1) := $$(CFG_GCCISH_CFLAGS_$(1)) -m64
 endif
+endif
 
 $$(COMPRT_LIB_$(1)): $$(COMPRT_DEPS) $$(MKFILE_DEPS)
 	@$$(call E, make: compiler-rt)

mk/target.mk

@@ -220,3 +220,40 @@ $(foreach target,$(CFG_TARGET), \
  $(foreach crate,$(CRATES), \
   $(foreach tool,$(NATIVE_TOOL_DEPS_$(crate)_T_$(target)), \
    $(eval $(call MOVE_TOOLS_TO_SNAPSHOT_HOST_DIR,0,$(target),$(BOOTSTRAP_FROM_$(target)),$(crate),$(tool))))))
+
+# For MSVC targets we need to set up some environment variables for the linker
+# to work correctly when building Rust crates. These two variables are:
+#
+# - LIB tells the linker the default search path for finding system libraries,
+#   for example kernel32.dll
+# - PATH needs to be modified to ensure that MSVC's link.exe is first in the
+#   path instead of MinGW's /usr/bin/link.exe (entirely unrelated)
+#
+# The values for these variables are detected by the configure script.
+define SETUP_LIB_MSVC_ENV_VARS
+ifeq ($$(findstring msvc,$(2)),msvc)
+$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): \
+	export LIB := $$(CFG_MSVC_LIB_PATH_$$(HOST_$(2)))
+$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): \
+	export PATH := $$(CFG_MSVC_BINDIR_$$(HOST_$(2))):$$(PATH)
+endif
+endef
+define SETUP_TOOL_MSVC_ENV_VARS
+ifeq ($$(findstring msvc,$(2)),msvc)
+$$(TBIN$(1)_T_$(2)_H_$(3))/$(4)$$(X_$(2)): \
+	export LIB := $$(CFG_MSVC_LIB_PATH_$$(HOST_$(2)))
+$$(TBIN$(1)_T_$(2)_H_$(3))/$(4)$$(X_$(2)): \
+	export PATH := $$(CFG_MSVC_BINDIR_$$(HOST_$(2))):$$(PATH)
+endif
+endef
+
+$(foreach host,$(CFG_HOST), \
+ $(foreach target,$(CFG_TARGET), \
+  $(foreach stage,$(STAGES), \
+   $(foreach crate,$(CRATES), \
+    $(eval $(call SETUP_LIB_MSVC_ENV_VARS,$(stage),$(target),$(host),$(crate)))))))
+$(foreach host,$(CFG_HOST), \
+ $(foreach target,$(CFG_TARGET), \
+  $(foreach stage,$(STAGES), \
+   $(foreach tool,$(TOOLS), \
+    $(eval $(call SETUP_TOOL_MSVC_ENV_VARS,$(stage),$(target),$(host),$(tool)))))))

src/libcore/num/f32.rs

@@ -215,13 +215,37 @@ impl Float for f32 {
     /// Rounds towards minus infinity.
     #[inline]
     fn floor(self) -> f32 {
-        unsafe { intrinsics::floorf32(self) }
+        return floorf(self);
+
+        // On MSVC LLVM will lower many math intrinsics to a call to the
+        // corresponding function. On MSVC, however, many of these functions
+        // aren't actually available as symbols to call, but rather they are all
+        // `static inline` functions in header files. This means that from a C
+        // perspective it's "compatible", but not so much from an ABI
+        // perspective (which we're worried about).
+        //
+        // The inline header functions always just cast to a f64 and do their
+        // operation, so we do that here as well, but only for MSVC targets.
+        //
+        // Note that there are many MSVC-specific float operations which
+        // redirect to this comment, so `floorf` is just one case of a missing
+        // function on MSVC, but there are many others elsewhere.
+        #[cfg(target_env = "msvc")]
+        fn floorf(f: f32) -> f32 { (f as f64).floor() as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn floorf(f: f32) -> f32 { unsafe { intrinsics::floorf32(f) } }
     }
 
     /// Rounds towards plus infinity.
     #[inline]
     fn ceil(self) -> f32 {
-        unsafe { intrinsics::ceilf32(self) }
+        return ceilf(self);
+
+        // see notes above in `floor`
+        #[cfg(target_env = "msvc")]
+        fn ceilf(f: f32) -> f32 { (f as f64).ceil() as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn ceilf(f: f32) -> f32 { unsafe { intrinsics::ceilf32(f) } }
     }
 
     /// Rounds to nearest integer. Rounds half-way cases away from zero.
@@ -299,7 +323,13 @@ impl Float for f32 {
 
     #[inline]
     fn powf(self, n: f32) -> f32 {
-        unsafe { intrinsics::powf32(self, n) }
+        return powf(self, n);
+
+        // see notes above in `floor`
+        #[cfg(target_env = "msvc")]
+        fn powf(f: f32, n: f32) -> f32 { (f as f64).powf(n as f64) as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn powf(f: f32, n: f32) -> f32 { unsafe { intrinsics::powf32(f, n) } }
     }
 
     #[inline]
@@ -317,7 +347,13 @@ impl Float for f32 {
     /// Returns the exponential of the number.
     #[inline]
     fn exp(self) -> f32 {
-        unsafe { intrinsics::expf32(self) }
+        return expf(self);
+
+        // see notes above in `floor`
+        #[cfg(target_env = "msvc")]
+        fn expf(f: f32) -> f32 { (f as f64).exp() as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn expf(f: f32) -> f32 { unsafe { intrinsics::expf32(f) } }
     }
 
     /// Returns 2 raised to the power of the number.
@@ -329,7 +365,13 @@ impl Float for f32 {
     /// Returns the natural logarithm of the number.
     #[inline]
     fn ln(self) -> f32 {
-        unsafe { intrinsics::logf32(self) }
+        return logf(self);
+
+        // see notes above in `floor`
+        #[cfg(target_env = "msvc")]
+        fn logf(f: f32) -> f32 { (f as f64).ln() as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn logf(f: f32) -> f32 { unsafe { intrinsics::logf32(f) } }
     }
 
     /// Returns the logarithm of the number with respect to an arbitrary base.
@@ -345,7 +387,13 @@ impl Float for f32 {
     /// Returns the base 10 logarithm of the number.
     #[inline]
     fn log10(self) -> f32 {
-        unsafe { intrinsics::log10f32(self) }
+        return log10f(self);
+
+        // see notes above in `floor`
+        #[cfg(target_env = "msvc")]
+        fn log10f(f: f32) -> f32 { (f as f64).log10() as f32 }
+        #[cfg(not(target_env = "msvc"))]
+        fn log10f(f: f32) -> f32 { unsafe { intrinsics::log10f32(f) } }
     }
 
     /// Converts to degrees, assuming the number is in radians.