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freebsd-skq/share/mk/bsd.compiler.mk
Brooks Davis e268fd0a02 Support initializing stack variables on function entry 
There are two options:
 - WITH_INIT_ALL_ZERO: Zero all variables on the stack.
 - WITH_INIT_ALL_PATTERN: Initialize variables with well-defined patterns.

The exact pattern are a compiler implementation detail and vary by type.
They are somewhat documented in the LLVM commit message:
https://reviews.llvm.org/rL349442
I've used WITH_INIT_ALL_* to match Microsoft's InitAll feature rather
than naming them after the LLVM specific compiler flags.

In a range of consumer products, options like these are used in
both debug and production builds with debugs builds using patterns
(intended to provoke crashes on use of uninitialized values) and
production using zeros (deemed more likely to lead to harmless
misbehavior or NULL-pointer dereferences).

Reviewed by:	emaste
Obtained from:	CheriBSD
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D27131
2020-11-10 19:15:13 +00:00

246 lines
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Makefile
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# $FreeBSD$
# Setup variables for the compiler
#
# COMPILER_TYPE is the major type of compiler. Currently gcc and clang support
# automatic detection. Other compiler types can be shoe-horned in, but require
# explicit setting of the compiler type. The compiler type can also be set
# explicitly if, say, you install gcc as clang...
#
# COMPILER_VERSION is a numeric constant equal to:
# major * 10000 + minor * 100 + tiny
# It too can be overridden on the command line. When testing it, be sure to
# make sure that you are limiting the test to a specific compiler. Testing
# against 30300 for gcc likely isn't what you wanted (since versions of gcc
# prior to 4.2 likely have no prayer of working).
#
# COMPILER_FREEBSD_VERSION is the compiler's __FreeBSD_cc_version value.
#
# COMPILER_FEATURES will contain one or more of the following, based on
# compiler support for that feature:
#
# - c++17: supports full (or nearly full) C++17 programming environment.
# - c++14: supports full (or nearly full) C++14 programming environment.
# - c++11: supports full (or nearly full) C++11 programming environment.
# - retpoline: supports the retpoline speculative execution vulnerability
# mitigation.
# - init-all: supports stack variable initialization.
#
# These variables with an X_ prefix will also be provided if XCC is set.
#
# This file may be included multiple times, but only has effect the first time.
#
.if !target(__<bsd.compiler.mk>__)
__<bsd.compiler.mk>__:
.include <bsd.opts.mk>
.if defined(_NO_INCLUDE_COMPILERMK)
# If _NO_INCLUDE_COMPILERMK is set we are doing a make obj/cleandir/cleanobj
# and might not have a valid compiler in $PATH yet. In this case just set the
# variables that are expected by the other .mk files and return
COMPILER_TYPE=none
X_COMPILER_TYPE=none
COMPILER_VERSION=0
X_COMPILER_VERSION=0
COMPILER_FEATURES=none
.else
# command = /usr/local/bin/ccache cc ...
# wrapper = /usr/local/libexec/ccache/cc ...
CCACHE_BUILD_TYPE?= command
# Handle ccache after CC is determined, but not if CC/CXX are already
# overridden with a manual setup.
.if ${MK_CCACHE_BUILD:Uno} == "yes" && \
!make(test-system-*) && !make(print-dir) && !make(showconfig) && \
(${CC:M*ccache/world/*} == "" || ${CXX:M*ccache/world/*} == "")
# CC is always prepended with the ccache wrapper rather than modifying
# PATH since it is more clear that ccache is used and avoids wasting time
# for mkdep/linking/asm builds.
LOCALBASE?= /usr/local
CCACHE_WRAPPER_PATH?= ${LOCALBASE}/libexec/ccache
CCACHE_BIN?= ${LOCALBASE}/bin/ccache
.if exists(${CCACHE_BIN})
# Export to ensure sub-makes can filter it out for mkdep/linking and
# to chain down into kernel build which won't include this file.
.export CCACHE_BIN
# Expand and export some variables so they may be based on make vars.
# This allows doing something like the following in the environment:
# CCACHE_BASEDIR='${SRCTOP:H}' MAKEOBJDIRPREFIX='${SRCTOP:H}/obj'
.for var in CCACHE_LOGFILE CCACHE_BASEDIR
.if defined(${var})
${var}:= ${${var}}
.export ${var}
.endif
.endfor
# Handle bootstrapped compiler changes properly by hashing their content
# rather than checking mtime. For external compilers it should be safe
# to use the more optimal mtime check.
# XXX: CCACHE_COMPILERCHECK= string:<compiler_version, compiler_build_rev, compiler_patch_rev, compiler_default_target, compiler_default_sysroot>
.if ${CC:N${CCACHE_BIN}:[1]:M/*} == ""
CCACHE_COMPILERCHECK?= content
.else
CCACHE_COMPILERCHECK?= mtime
.endif
.export CCACHE_COMPILERCHECK
# Ensure no bogus CCACHE_PATH leaks in which might avoid the in-tree compiler.
.if !empty(CCACHE_PATH)
CCACHE_PATH=
.export CCACHE_PATH
.endif
.if ${CCACHE_BUILD_TYPE} == "command"
# Remove ccache from the PATH to prevent double calls and wasted CPP/LD time.
PATH:= ${PATH:C,:?${CCACHE_WRAPPER_PATH}(/world)?(:$)?,,g}
# Override various toolchain vars.
.for var in CC CXX HOST_CC HOST_CXX
.if defined(${var}) && ${${var}:M${CCACHE_BIN}} == ""
${var}:= ${CCACHE_BIN} ${${var}}
.endif
.endfor
.else
# Need to ensure CCACHE_WRAPPER_PATH is the first in ${PATH}
PATH:= ${PATH:C,:?${CCACHE_WRAPPER_PATH}(/world)?(:$)?,,g}
PATH:= ${CCACHE_WRAPPER_PATH}:${PATH}
CCACHE_WRAPPER_PATH_PFX= ${CCACHE_WRAPPER_PATH}:
.endif # ${CCACHE_BUILD_TYPE} == "command"
# GCC does not need the CCACHE_CPP2 hack enabled by default in devel/ccache.
# The port enables it due to ccache passing preprocessed C to clang
# which fails with -Wparentheses-equality, -Wtautological-compare, and
# -Wself-assign on macro-expanded lines.
.if defined(COMPILER_TYPE) && ${COMPILER_TYPE} == "gcc"
CCACHE_NOCPP2= 1
.export CCACHE_NOCPP2
.endif
# Canonicalize CCACHE_DIR for meta mode usage.
.if !defined(CCACHE_DIR)
CCACHE_DIR!= ${CCACHE_BIN} -p | awk '$$2 == "cache_dir" {print $$4}'
.export CCACHE_DIR
.endif
.if !empty(CCACHE_DIR) && empty(.MAKE.META.IGNORE_PATHS:M${CCACHE_DIR})
CCACHE_DIR:= ${CCACHE_DIR:tA}
.MAKE.META.IGNORE_PATHS+= ${CCACHE_DIR}
.export CCACHE_DIR
.endif
# ccache doesn't affect build output so let it slide for meta mode
# comparisons.
.MAKE.META.IGNORE_PATHS+= ${CCACHE_BIN}
ccache-print-options: .PHONY
@${CCACHE_BIN} -p
.endif # exists(${CCACHE_BIN})
.endif # ${MK_CCACHE_BUILD} == "yes"
_cc_vars=CC $${_empty_var_}
.if !empty(_WANT_TOOLCHAIN_CROSS_VARS)
# Only the toplevel makefile needs to compute the X_COMPILER_* variables.
# Skipping the computation of the unused X_COMPILER_* in the subdirectory
# makefiles can save a noticeable amount of time when walking the whole source
# tree (e.g. during make includes, etc.).
_cc_vars+=XCC X_
.endif
.for cc X_ in ${_cc_vars}
.if ${cc} == "CC" || !empty(XCC)
# Try to import COMPILER_TYPE and COMPILER_VERSION from parent make.
# The value is only used/exported for the same environment that impacts
# CC and COMPILER_* settings here.
_exported_vars= ${X_}COMPILER_TYPE ${X_}COMPILER_VERSION \
${X_}COMPILER_FREEBSD_VERSION ${X_}COMPILER_RESOURCE_DIR
${X_}_cc_hash= ${${cc}}${MACHINE}${PATH}
${X_}_cc_hash:= ${${X_}_cc_hash:hash}
# Only import if none of the vars are set differently somehow else.
_can_export= yes
.for var in ${_exported_vars}
.if defined(${var}) && (!defined(${var}__${${X_}_cc_hash}) || ${${var}__${${X_}_cc_hash}} != ${${var}})
.if defined(${var}__${${X_}_ld_hash})
.info "Cannot import ${X_}COMPILER variables since cached ${var} is different: ${${var}__${${X_}_cc_hash}} != ${${var}}"
.endif
_can_export= no
.endif
.endfor
.if ${_can_export} == yes
.for var in ${_exported_vars}
.if defined(${var}__${${X_}_cc_hash})
${var}= ${${var}__${${X_}_cc_hash}}
.endif
.endfor
.endif
.if ${cc} == "CC" || (${cc} == "XCC" && ${XCC} != ${CC})
.if ${MACHINE} == "common"
# common is a pseudo machine for architecture independent
# generated files - thus there is no compiler.
${X_}COMPILER_TYPE= none
${X_}COMPILER_VERSION= 0
${X_}COMPILER_FREEBSD_VERSION= 0
.elif !defined(${X_}COMPILER_TYPE) || !defined(${X_}COMPILER_VERSION)
_v!= ${${cc}:N${CCACHE_BIN}} --version || echo 0.0.0
.if !defined(${X_}COMPILER_TYPE)
. if ${${cc}:T:M*gcc*}
${X_}COMPILER_TYPE:= gcc
. elif ${${cc}:T:M*clang*}
${X_}COMPILER_TYPE:= clang
. elif ${_v:Mgcc}
${X_}COMPILER_TYPE:= gcc
. elif ${_v:M\(GCC\)} || ${_v:M*GNU}
${X_}COMPILER_TYPE:= gcc
. elif ${_v:Mclang} || ${_v:M(clang-*.*.*)}
${X_}COMPILER_TYPE:= clang
. else
.error Unable to determine compiler type for ${cc}=${${cc}}. Consider setting ${X_}COMPILER_TYPE.
. endif
.endif
.if !defined(${X_}COMPILER_VERSION)
${X_}COMPILER_VERSION!=echo "${_v:M[1-9]*.[0-9]*}" | awk -F. '{print $$1 * 10000 + $$2 * 100 + $$3;}'
.endif
.undef _v
.endif
.if !defined(${X_}COMPILER_FREEBSD_VERSION)
${X_}COMPILER_FREEBSD_VERSION!= { echo "__FreeBSD_cc_version" | ${${cc}:N${CCACHE_BIN}} -E - 2>/dev/null || echo __FreeBSD_cc_version; } | sed -n '$$p'
# If we get a literal "__FreeBSD_cc_version" back then the compiler
# is a non-FreeBSD build that doesn't support it or some other error
# occurred.
.if ${${X_}COMPILER_FREEBSD_VERSION} == "__FreeBSD_cc_version"
${X_}COMPILER_FREEBSD_VERSION= unknown
.endif
.endif
.if !defined(${X_}COMPILER_RESOURCE_DIR)
${X_}COMPILER_RESOURCE_DIR!= ${${cc}:N${CCACHE_BIN}} -print-resource-dir 2>/dev/null || echo unknown
.endif
${X_}COMPILER_FEATURES= c++11 c++14
.if ${${X_}COMPILER_TYPE} == "clang" || \
(${${X_}COMPILER_TYPE} == "gcc" && ${${X_}COMPILER_VERSION} >= 70000)
${X_}COMPILER_FEATURES+= c++17
.endif
.if ${${X_}COMPILER_TYPE} == "clang"
${X_}COMPILER_FEATURES+= retpoline init-all
.endif
.else
# Use CC's values
X_COMPILER_TYPE= ${COMPILER_TYPE}
X_COMPILER_VERSION= ${COMPILER_VERSION}
X_COMPILER_FREEBSD_VERSION= ${COMPILER_FREEBSD_VERSION}
X_COMPILER_FEATURES= ${COMPILER_FEATURES}
X_COMPILER_RESOURCE_DIR= ${COMPILER_RESOURCE_DIR}
.endif # ${cc} == "CC" || (${cc} == "XCC" && ${XCC} != ${CC})
# Export the values so sub-makes don't have to look them up again, using the
# hash key computed above.
.for var in ${_exported_vars}
${var}__${${X_}_cc_hash}:= ${${var}}
.export-env ${var}__${${X_}_cc_hash}
.undef ${var}__${${X_}_cc_hash}
.endfor
.endif # ${cc} == "CC" || !empty(XCC)
.endfor # .for cc in CC XCC
.if !defined(_NO_INCLUDE_LINKERMK)
.include <bsd.linker.mk>
.endif
.endif # defined(_NO_INCLUDE_COMPILERMK)
.endif # !target(__<bsd.compiler.mk>__)
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