lib: establish Zircon libc++ and KTL foundation

1 files changed, 36 insertions, 9 deletions

diff --git a/scripts/build/toolchain.mk b/scripts/build/toolchain.mk
index 49d4f0a..d244981 100644
--- a/scripts/build/toolchain.mk
+++ b/scripts/build/toolchain.mk
@@ -10,10 +10,30 @@ LLVM          ?= 0
 LLVM_VERSION  ?= 20
 LD_TYPE       ?= bfd
 LLVM_BINUTILS ?= 0
-CXX_STDLIB    ?= libstdc++
+CXX_STDLIB    ?= libc++
 CXX_ABI       ?= lume
 COMPILER_RUNTIME ?= compiler-default
 
+# One pinned libc++ header snapshot is shared by GCC and Clang.  Platform C
+# declarations and libc++ configuration come from the Zircon libc/KTL layer,
+# not from a Linux or Fuchsia userland __config_site.
+LIBCXX_ROOT ?= third_party/libcxx
+LIBCXX_INCLUDE := $(LIBCXX_ROOT)/include/c++/v1
+KTL_INCLUDE := lib/ktl/include
+KTL_AFTER_INCLUDE := lib/ktl/include-after
+KERNEL_LIBC_INCLUDE := lib/libc/include
+KERNEL_LIBC_AFTER_INCLUDE := lib/libc/include-after
+
+ifeq ($(wildcard $(LIBCXX_INCLUDE)/__config),)
+$(error missing pinned libc++ headers under '$(LIBCXX_INCLUDE)')
+endif
+ifeq ($(wildcard $(KTL_INCLUDE)/__config_site),)
+$(error missing KTL libc++ configuration under '$(KTL_INCLUDE)')
+endif
+ifneq ($(CXX_STDLIB),libc++)
+$(error unsupported CXX_STDLIB '$(CXX_STDLIB)' (LumeOS uses its pinned libc++ headers))
+endif
+
 GCC_TOOLCHAIN ?=
 CROSS_COMPILE ?=
 
@@ -64,29 +84,36 @@ CC  := $(CLANG)
 CXX := $(CLANGXX)
 COMPILER_FAMILY := clang
 TOOLCHAIN_CFLAGS := $(CLANG_TARGET_FLAGS)
-ifeq ($(CXX_STDLIB),libstdc++)
-TOOLCHAIN_CXXFLAGS := -stdlib=libstdc++
-else
-$(error unsupported CXX_STDLIB '$(CXX_STDLIB)' for the current imported runtime)
-endif
+TOOLCHAIN_CXXFLAGS :=
+COMPILER_RESOURCE_DIR := $(strip $(shell $(CXX) $(CLANG_TARGET_FLAGS) -print-resource-dir 2>/dev/null))
+COMPILER_RESOURCE_INCLUDE := $(COMPILER_RESOURCE_DIR)/include
 ifeq ($(LD_TYPE),lld)
 LD := $(LLD)
 LINKER_FAMILY := lld
 else
-ifneq ($(CXX_STDLIB),libstdc++)
-$(error GCC configuration currently requires CXX_STDLIB=libstdc++)
-endif
 LD := $(CROSS_COMPILE)ld
 LINKER_FAMILY := bfd
 endif
+
 else
 CC  := $(CROSS_COMPILE)gcc
 CXX := $(CROSS_COMPILE)g++
 LD  := $(CROSS_COMPILE)ld
 COMPILER_FAMILY := gcc
 LINKER_FAMILY := bfd
+COMPILER_RESOURCE_INCLUDE := $(strip $(shell $(CXX) -print-file-name=include 2>/dev/null))
 endif
 
+ifeq ($(wildcard $(COMPILER_RESOURCE_INCLUDE)/stddef.h),)
+$(error missing compiler resource headers under '$(COMPILER_RESOURCE_INCLUDE)')
+endif
+
+# Kernel and phys code must not observe the Linux target sysroot.  Supply only
+# compiler intrinsic headers explicitly; the target graph provides the kernel
+# libc and KTL layers, followed by the pinned libc++ headers for C++.
+TOOLCHAIN_CFLAGS += -nostdinc -isystem $(COMPILER_RESOURCE_INCLUDE)
+TOOLCHAIN_CXXFLAGS += -isystem $(LIBCXX_INCLUDE)
+
 ifeq ($(LLVM_BINUTILS),1)
 AR      := llvm-ar$(CLANG_SUFFIX)
 NM      := llvm-nm$(CLANG_SUFFIX)