Add a separate linker wrapper

This CL adds a new device and host linker wrapper.  This allows us to
separate out arguments that are specific to different stages of the
build process and be more precise in our configuration of the rustc
build process.

Test: ./toolchain/android_rust/build.py
Change-Id: Iea0aff461f667226deaca1e19fec35d8576feabe

Author: chriswailes

build_platform.py

@@ -14,6 +14,12 @@ def system() -> str:
         return 'darwin'
     raise RuntimeError("Unknown System: " + sys)
 
+def is_linux() -> bool:
+    return platform.system() == 'Linux'
+
+def is_darwin() -> bool:
+    return platform.system() == 'Darwin'
+
 def prebuilt() -> str:
     """Returns the prebuilt subdirectory for prebuilts which do not use
     subarch specialization."""

config.py

@@ -29,29 +29,16 @@
 
 ANDROID_TARGET_VERSION: str = '31'
 
-CONFIG_TOML_TEMPLATE:       Path = TEMPLATES_PATH / 'config.toml.template'
-DEVICE_CC_WRAPPER_TEMPLATE: Path = TEMPLATES_PATH / 'device_cc_wrapper.template'
-DEVICE_TARGET_TEMPLATE:     Path = TEMPLATES_PATH / 'device_target.template'
-HOST_CC_WRAPPER_TEMPLATE:   Path = TEMPLATES_PATH / 'host_cc_wrapper.template'
-HOST_CXX_WRAPPER_TEMPLATE:  Path = TEMPLATES_PATH / 'host_cxx_wrapper.template'
-HOST_TARGET_TEMPLATE:       Path = TEMPLATES_PATH / 'host_target.template'
-
-# Add the path at which libc++ can be found in Android checkouts
-CXX_LINKER_FLAGS: str = ' -Wl,-rpath,'
-if build_platform.system() == 'darwin':
-    CXX_LINKER_FLAGS += '@loader_path/../lib64'
-    CXX_LINKER_FLAGS += ' -mmacosx-version-min=10.14'
-else:
-    CXX_LINKER_FLAGS += '\\$ORIGIN/../lib64'
-# Add the path at which libc++ can be found during the build
-CXX_LINKER_FLAGS += (' -L' + LLVM_CXX_RUNTIME_PATH.as_posix() +
-                     ' -Wl,-rpath,' + LLVM_CXX_RUNTIME_PATH.as_posix())
-
-LD_OPTIONS: str = None
-if build_platform.system() == 'linux':
-    LD_OPTIONS = '-fuse-ld=lld -Wno-unused-command-line-argument'
-else:
-    LD_OPTIONS = ''
+CONFIG_TOML_TEMPLATE:           Path = TEMPLATES_PATH / 'config.toml.template'
+DEVICE_CC_WRAPPER_TEMPLATE:     Path = TEMPLATES_PATH / 'device_cc_wrapper.template'
+DEVICE_LINKER_WRAPPER_TEMPLATE: Path = TEMPLATES_PATH / 'device_linker_wrapper.template'
+DEVICE_TARGET_TEMPLATE:         Path = TEMPLATES_PATH / 'device_target.template'
+HOST_CC_WRAPPER_TEMPLATE:       Path = TEMPLATES_PATH / 'host_cc_wrapper.template'
+HOST_CXX_WRAPPER_TEMPLATE:      Path = TEMPLATES_PATH / 'host_cxx_wrapper.template'
+HOST_LINKER_WRAPPER_TEMPLATE:   Path = TEMPLATES_PATH / 'host_linker_wrapper.template'
+HOST_TARGET_TEMPLATE:           Path = TEMPLATES_PATH / 'host_target.template'
+
+MACOSX_VERSION_FLAG: str = '-mmacosx-version-min=10.14'
 
 
 def instantiate_template_exec(template_path: Path, output_path: Path, **kwargs):
@@ -66,39 +53,47 @@ def instantiate_template_file(template_path: Path, output_path: Path, make_exec:
         output_path.chmod(output_path.stat().st_mode | stat.S_IEXEC)
 
 
-def host_config(target: str, toolchain_flags: str) -> str:
-    cc_wrapper_name  = OUT_PATH_WRAPPERS / ('clang-%s' % target)
-    cxx_wrapper_name = OUT_PATH_WRAPPERS / ('clang++-%s' % target)
+def host_config(target: str, macosx_flags: str, linker_flags: str) -> str:
+    cc_wrapper_name     = OUT_PATH_WRAPPERS / ('clang-%s' % target)
+    cxx_wrapper_name    = OUT_PATH_WRAPPERS / ('clang++-%s' % target)
+    linker_wrapper_name = OUT_PATH_WRAPPERS / ('linker-%s' % target)
 
     instantiate_template_exec(
         HOST_CC_WRAPPER_TEMPLATE,
         cc_wrapper_name,
         real_cc=CC_PATH,
-        ld_option=LD_OPTIONS,
         target=target,
-        toolchain_flags=toolchain_flags)
+        macosx_flags=macosx_flags)
 
     instantiate_template_exec(
         HOST_CXX_WRAPPER_TEMPLATE,
         cxx_wrapper_name,
         real_cxx=CXX_PATH,
-        ld_option=LD_OPTIONS,
         target=target,
-        toolchain_flags=toolchain_flags,
-        cxxstd=CXXSTD_PATH,
-        cxx_linker_flags=CXX_LINKER_FLAGS)
+        macosx_flags=macosx_flags,
+        cxxstd=CXXSTD_PATH)
+
+    instantiate_template_exec(
+        HOST_LINKER_WRAPPER_TEMPLATE,
+        linker_wrapper_name,
+        real_cxx=CXX_PATH,
+        target=target,
+        macosx_flags=macosx_flags,
+        linker_flags=linker_flags)
 
     with open(HOST_TARGET_TEMPLATE, 'r') as template_file:
         return Template(template_file.read()).substitute(
             target=target,
             cc=cc_wrapper_name,
             cxx=cxx_wrapper_name,
+            linker=linker_wrapper_name,
             ar=AR_PATH,
             ranlib=RANLIB_PATH)
 
 
 def device_config(target: str) -> str:
-    cc_wrapper_name = OUT_PATH_WRAPPERS / ('clang-%s' % target)
+    cc_wrapper_name     = OUT_PATH_WRAPPERS / ('clang-%s' % target)
+    linker_wrapper_name = OUT_PATH_WRAPPERS / ('linker-%s' % target)
 
     clang_target = target + ANDROID_TARGET_VERSION
 
@@ -109,28 +104,51 @@ def device_config(target: str) -> str:
         target=clang_target,
         sysroot=NDK_SYSROOT_PATH)
 
+    instantiate_template_exec(
+        DEVICE_LINKER_WRAPPER_TEMPLATE,
+        linker_wrapper_name,
+        real_cc=CC_PATH,
+        target=clang_target,
+        sysroot=NDK_SYSROOT_PATH)
+
     with open(DEVICE_TARGET_TEMPLATE, 'r') as template_file:
         return Template(template_file.read()).substitute(
-            target=target, cc=cc_wrapper_name, ar=AR_PATH)
+            target=target,
+            cc=cc_wrapper_name,
+            linker=linker_wrapper_name,
+            ar=AR_PATH)
 
 
 def configure():
-    """Generates config.toml for the rustc build."""
-    host_toolchain_flags = None
+    """Generates config.toml and compiler wrapers for the rustc build."""
+
+    macosx_flags:          str = ''
+    host_ld_selector:      str = '-fuse-ld=lld' if build_platform.is_linux() else ''
+    host_bin_search:       str = ('-B' + GCC_TOOLCHAIN_PATH.as_posix()) if build_platform.is_linux() else ''
+    host_llvm_libpath:     str = '-L' + LLVM_CXX_RUNTIME_PATH.as_posix()
+    host_rpath_buildtime:  str = '-Wl,-rpath,' + LLVM_CXX_RUNTIME_PATH.as_posix()
+    host_rpath_runtime:    str = '-Wl,-rpath,' + (
+        '$ORIGIN/../lib64' if build_platform.is_linux() else '@loader_path/../lib64')
 
-    if build_platform.system() == 'darwin':
+    if build_platform.is_darwin():
         # Apple removed the normal sysroot at / on Mojave+, so we need
         # to go hunt for it on OSX
         # On pre-Mojave, this command will output the empty string.
         output = subprocess.check_output(
             ['xcrun', '--sdk', 'macosx', '--show-sdk-path'])
-        host_toolchain_flags = "--sysroot " + output.rstrip().decode('utf-8')
-    else:
-        # On Linux build hosts we need to set the path to the gcc toolchain.
-        host_toolchain_flags = "-B " + GCC_TOOLCHAIN_PATH.as_posix()
+        macosx_flags = (
+            MACOSX_VERSION_FLAG +
+            " --sysroot " + output.rstrip().decode('utf-8'))
+
+    host_linker_flags = ' '.join([
+        host_ld_selector,
+        host_bin_search,
+        host_llvm_libpath,
+        host_rpath_buildtime,
+        host_rpath_runtime])
 
     host_configs = '\n'.join(
-        [host_config(target, host_toolchain_flags) for target in HOST_TARGETS])
+        [host_config(target, macosx_flags, host_linker_flags) for target in HOST_TARGETS])
     device_configs = '\n'.join(
         [device_config(target) for target in DEVICE_TARGETS])
 
@@ -140,6 +158,7 @@ def configure():
     instantiate_template_file(
         CONFIG_TOML_TEMPLATE,
         OUT_PATH_RUST_SOURCE / 'config.toml',
+        llvm_ldflags=host_linker_flags,
         all_targets=all_targets,
         cargo=CARGO_PATH,
         rustc=RUSTC_PATH,

do_build.py

@@ -98,7 +98,7 @@ def main():
         ]] + [env['PATH']])
 
     # Only adjust the library path on Linux - on OSX, use the devtools curl
-    if build_platform.system() == 'linux':
+    if build_platform.is_linux():
         if 'LIBRARY_PATH' in env:
             old_library_path = ':{0}'.format(env['LIBRARY_PATH'])
         else:
@@ -168,7 +168,7 @@ def main():
         sys.exit(ec)
 
     # Install sources
-    if build_platform.system() == 'linux':
+    if build_platform.is_linux():
         shutil.rmtree(OUT_PATH_STDLIB_SRCS, ignore_errors=True)
         for stdlib in STDLIB_SOURCES:
             shutil.copytree(OUT_PATH_RUST_SOURCE / stdlib, OUT_PATH_STDLIB_SRCS / stdlib)
@@ -187,7 +187,7 @@ def main():
         OUT_PATH_PACKAGE / 'bin' / 'rustdoc'])
 
     # Install the libc++ library to out/package/lib64/
-    if build_platform.system() == 'darwin':
+    if build_platform.is_darwin():
         libcxx_name = 'libc++.dylib'
     else:
         libcxx_name = 'libc++.so.1'
@@ -199,7 +199,7 @@ def main():
 
     # Some stdlib crates might include Android.mk or Android.bp files.
     # If they do, filter them out.
-    if build_platform.system() == 'linux':
+    if build_platform.is_linux():
         for f in OUT_PATH_STDLIB_SRCS.glob('**/Android.{mk,bp}'):
             f.unlink()
 

patches/rustc-0017-Modify-Rust-build-system-to-correctly-handle-use-lib.patch

@@ -0,0 +1,31 @@
+From 7c73299dbc68fb7a59637d98fc56fdbcaf7ab67d Mon Sep 17 00:00:00 2001
+From: Chris Wailes <[email protected]>
+Date: Mon, 13 Sep 2021 23:58:25 -0700
+Subject: [PATCH] Modify Rust build system to correctly handle use-libcxx
+
+This CL modifies the Rust build system so that it will pass
+LLVM_ENABLE_LIBCXX when the use-libcxx option is enabled in config.toml.
+
+Change-Id: Ibc1285f49843238aa912606d87295dd19f24ae6e
+---
+ src/bootstrap/native.rs | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
+index 1be414b29a..849c0f0cc1 100644
+--- a/src/bootstrap/native.rs
++++ b/src/bootstrap/native.rs
+@@ -182,6 +182,10 @@ impl Step for Llvm {
+             .define("LLVM_TARGET_ARCH", target_native.split('-').next().unwrap())
+             .define("LLVM_DEFAULT_TARGET_TRIPLE", target_native);
+ 
++        if builder.config.llvm_use_libcxx {
++            cfg.define("LLVM_ENABLE_LIBCXX", "ON");
++        }
++
+         if target != "aarch64-apple-darwin" && !target.contains("windows") {
+             cfg.define("LLVM_ENABLE_ZLIB", "ON");
+         } else {
+-- 
+2.33.0.309.g3052b89438-goog
+

templates/config.toml.template

@@ -1,9 +1,12 @@
 changelog-seen = 2
+
 [llvm]
 ninja = true
 targets = "AArch64;ARM;X86"
 experimental-targets = ""
+ldflags = "$llvm_ldflags"
 use-libcxx = true
+
 [build]
 target = $all_targets
 cargo = "$cargo"
@@ -19,12 +22,16 @@ full-bootstrap = true
 extended = true
 tools = ["cargo", "clippy", "rustfmt", "rust-analyzer"]
 cargo-native-static = true
+
 [install]
 prefix = "/"
 sysconfdir = "etc"
+
 [rust]
 channel = "dev"
 remap-debuginfo = true
 deny-warnings = false
+
 $host_configs
+
 $device_configs

templates/device_cc_wrapper.template

@@ -1,2 +1,2 @@
 #!/bin/bash
-$real_cc $${*/"-lgcc"} -fuse-ld=lld -Wno-unused-command-line-argument --target=$target --sysroot=$sysroot
+$real_cc $$* --target=$target --sysroot=$sysroot

templates/device_linker_wrapper.template

@@ -0,0 +1,2 @@
+#!/bin/bash
+$real_cc $${*/"-lgcc"} -fuse-ld=lld --target=$target --sysroot=$sysroot

templates/device_target.template

@@ -1,3 +1,4 @@
 [target.$target]
 cc = "$cc"
+linker = "$linker"
 ar = "$ar"

templates/host_cc_wrapper.template

@@ -1,2 +1,2 @@
 #!/bin/bash
-$real_cc $$* $ld_option --target=$target $toolchain_flags
+$real_cc $$* --target=$target $macosx_flags

templates/host_cxx_wrapper.template

@@ -1,2 +1,2 @@
 #!/bin/bash
-$real_cxx -I$cxxstd $$* $ld_option --target=$target $toolchain_flags $cxx_linker_flags -stdlib=libc++
+$real_cxx $$* --target=$target -stdlib=libc++ $macosx_flags -I$cxxstd

templates/host_linker_wrapper.template

@@ -0,0 +1,2 @@
+#!/bin/bash
+$real_cxx $$* --target=$target -stdlib=libc++ $macosx_flags $linker_flags

templates/host_target.template

@@ -1,6 +1,6 @@
 [target.$target]
 cc = "$cc"
 cxx = "$cxx"
+linker = "$linker"
 ar = "$ar"
-ranlib = "$ranlib"
-linker = "$cxx"
+ranlib = "$ranlib"