From 62f8ef3a7fc5f4d68764566d4968db1585126604 Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Tue, 4 Feb 2025 00:59:26 -0500
Subject: [PATCH] BuildSetup: Clean up HOST_KERNEL and linking rules.

 * Drop all HOST_KERNEL_* definitions, they aren't used or needed
   anymore, it seems.

 * Use --no-as-needed unconditionally; it works under Clang+LLD now.
   (and indeed it's still needed for the "unzip" host tool to
   compile and link properly.)

 * Drop --copy-dt-needed-entries. It was added around the time of
   GCC 10, but it seems that it's not needed anymore, or at least I
   did a minimum build having compiled the host tools without it
   and all seemed to be fine. Furthermore, it seems lld doesn't support
   it, so this fixes the build under FreeBSD and other platforms
   that also don't use ld.bfd same as Darwin/macOS.
---
 build/jam/BuildSetup | 47 ++++++++------------------------------------
 1 file changed, 8 insertions(+), 39 deletions(-)

diff --git a/build/jam/BuildSetup b/build/jam/BuildSetup
index 9f7eab2d0e..f5df4c5774 100644
--- a/build/jam/BuildSetup
+++ b/build/jam/BuildSetup
@@ -212,6 +212,11 @@ HOST_LINKFLAGS		?= $(HOST_GCC_BASE_FLAGS) $(LINKFLAGS) ;
 HOST_DEFINES		?= $(DEFINES) ;
 HOST_HDRS			?= $(HDRS) ;
 
+# we shouldn't build anything for the kernel under HOST
+HOST_KERNEL_ARCH = host ;
+HOST_KERNEL_CCFLAGS = host ;
+HOST_KERNEL_C++FLAGS = host ;
+
 
 # split up HOST_AR into the command name and flags
 HOST_AR				= [ Match "([^ ]*) *(.*)" : $(HOST_AR[1]) ]
@@ -247,7 +252,6 @@ if $(HOST_CPU) = riscv && $(HOST_PLATFORM_IS_64_BIT) {
 }
 HOST_ARCH ?= $(HOST_CPU) ;
 HOST_ARCHS = $(HOST_ARCH) ;
-HOST_KERNEL_ARCH = host ;
 
 # set packaging architecture
 HOST_PACKAGING_ARCH		?= $(HOST_CPU) ;
@@ -273,6 +277,9 @@ SetIncludePropertiesVariables HOST ;
 # assembler flags
 HOST_ASFLAGS = ;
 
+# linker flags
+HOST_LINKFLAGS += -Wl,--no-as-needed ;
+
 # C/C++ flags
 HOST_CCFLAGS += -Wno-multichar ;
 HOST_C++FLAGS += -Wno-multichar ;
@@ -282,45 +289,12 @@ HOST_PIC_C++FLAGS += -fPIC ;
 
 HOST_GCC_BASE_FLAGS += -fno-strict-aliasing -fno-delete-null-pointer-checks ;
 
-HOST_KERNEL_CCFLAGS += $(HOST_GCC_BASE_FLAGS) -finline -fno-builtin
-	-D_KERNEL_MODE ;
-HOST_KERNEL_C++FLAGS += $(HOST_GCC_BASE_FLAGS) -finline -fno-builtin
-	-fno-exceptions -D_KERNEL_MODE ;
-HOST_KERNEL_DEFINES += _KERNEL_MODE ;
-
-HOST_KERNEL_PIC_CCFLAGS = -fno-pic ;
-HOST_KERNEL_PIC_LINKFLAGS = ;
-if $(HOST_ARCH) = ppc {
-	# Build a position independent PPC kernel. We need to be able to relocate
-	# the kernel, since the virtual address space layout at boot time is not
-	# fixed.
-	HOST_KERNEL_PIC_CCFLAGS = -fPIE ;
-	HOST_KERNEL_PIC_LINKFLAGS = -shared -fPIE ;
-}
-if $(HOST_ARCH) = m68k {
-	# Build a position independent M68K kernel. We need to be able to relocate
-	# the kernel, since the virtual address space layout at boot time is not
-	# fixed.
-	HOST_KERNEL_PIC_CCFLAGS = $(HAIKU_KERNEL_PIC_CCFLAGS) ;
-	HOST_KERNEL_PIC_LINKFLAGS = $(HAIKU_KERNEL_PIC_LINKFLAGS) ;
-}
-
-if $(HOST_PLATFORM) != darwin {
-	# fix for new changes to DSO linking policies
-	HOST_LINKFLAGS += -Xlinker --no-as-needed ;
-	HOST_LINKFLAGS += -Wl,--copy-dt-needed-entries ;
-}
-
-
 # warning flags
 HOST_WARNING_CCFLAGS = -Wall -Wno-trigraphs -Wmissing-prototypes -Wpointer-arith
 	-Wcast-align -Wsign-compare ;
 HOST_WARNING_C++FLAGS = -Wall -Wno-trigraphs -Wno-ctor-dtor-privacy
 	-Woverloaded-virtual -Wpointer-arith -Wcast-align -Wsign-compare ;
 
-HOST_KERNEL_WARNING_CCFLAGS = -Wall -Wno-trigraphs -Wmissing-prototypes ;
-HOST_KERNEL_WARNING_C++FLAGS = -Wall -Wno-trigraphs ;
-
 HOST_WERROR_FLAGS = ;
 
 # debug flags
@@ -338,16 +312,11 @@ switch $(HOST_PLATFORM) {
 HOST_DEBUG_0_CCFLAGS = [ FDefines NDEBUG=$(NDEBUG) ] ;
 HOST_DEBUG_0_C++FLAGS = [ FDefines NDEBUG=$(NDEBUG) ] ;
 
-HOST_KERNEL_DEBUG_0_CCFLAGS = [ FDefines NDEBUG=$(NDEBUG) ] ;
-HOST_KERNEL_DEBUG_0_C++FLAGS = [ FDefines NDEBUG=$(NDEBUG) ] ;
-
 local level ;
 for level in $(HAIKU_DEBUG_LEVELS[2-]) {
 	local flags = $(hostDebugFlags) [ FDefines DEBUG=$(level) ] ;
 	HOST_DEBUG_$(level)_CCFLAGS			= $(flags) ;
 	HOST_DEBUG_$(level)_C++FLAGS		= $(flags) ;
-	HOST_KERNEL_DEBUG_$(level)_CCFLAGS	= $(flags) ;
-	HOST_KERNEL_DEBUG_$(level)_C++FLAGS	= $(flags) ;
 }
 
 # ld flags