build: determine toolchain tools dynamically

Since the introduction of the toolchain detection framework into the
build system, we have done determination and identification of the
toolchain(s) used for the build at the initialization of the build
system.

This incurs a large cost to the build every time - for every toolchain
that has been requested by the current makefile, we try to identify each
tool in the list of known tool classes, even if that tool doesn't
actually see any use.

For the clean and check-like targets we worked around this by disabling
most of the toolchains if we detect these targets, but this is
inflexible and not very reliable, and it still means that when building
normal targets we are incurring that cost for all tools whether they are
used or not.

This change instead modifies the toolchain detection framework to only
initialize a tool for a given toolchain when it is first used. This does
mean that we can no longer warn about an incorrectly-configured
toolchain at the beginning of build system invocation, but it has the
advantage of substantially reducing build time and the complexity of
*using* the framework (at the cost of an increase in complexity in the
framework itself).

Change-Id: I7f3d06b2eb58c1b26a846791a13b0037f32c8013
Signed-off-by: Chris Kay <chris.kay@arm.com>

Makefile

@@ -37,17 +37,6 @@ include ${MAKE_HELPERS_DIRECTORY}defaults.mk
 # Configure the toolchains used to build TF-A and its tools
 ################################################################################
 
-#
-# The clean and check targets do not behave correctly if the user's environment
-# does not appropriately configure a toolchain. While we try to find a permanent
-# solution to this, do not try to detect any toolchains if we are building
-# exclusively with targets which do not use any toolchain tools.
-#
-
-ifeq ($(filter-out check% %clean doc %tool,$(or $(MAKECMDGOALS),all)),)
-        toolchains :=
-endif
-
 include ${MAKE_HELPERS_DIRECTORY}toolchain.mk
 
 # Assertions enabled for DEBUG builds by default

lib/romlib/Makefile

@@ -4,12 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-ifeq ($(filter-out clean,$(or $(MAKECMDGOALS),all)),)
-        toolchains :=
-else
-        toolchains := aarch64
-endif
-
 include ../../make_helpers/build-rules.mk
 include ../../make_helpers/common.mk
 include ../../make_helpers/toolchain.mk

make_helpers/toolchain.mk

@@ -18,13 +18,74 @@
 ifndef toolchain-mk
         toolchain-mk := $(lastword $(MAKEFILE_LIST))
 
-        toolchains ?= host $(ARCH)
+        include $(dir $(toolchain-mk))build_env.mk
+        include $(dir $(toolchain-mk))utilities.mk
 
-        include $(dir $(lastword $(MAKEFILE_LIST)))build_env.mk
+        #
-        include $(dir $(lastword $(MAKEFILE_LIST)))utilities.mk
+        # Make assigns generic default values to `CC`, `CPP`, `AS`, etc. if they
+        # are not explicitly assigned values by the user. These are usually okay
+        # for very simple programs when building for the host system, but we
+        # need greater control over the toolchain flow.
+        #
+        # Therefore, we undefine these built-in variables if they have default
+        # values, so that we can provide our own default values later instead.
+        #
 
-        include $(addprefix $(dir $(lastword $(MAKEFILE_LIST)))toolchains/, \
+        ifeq ($(origin CC),default)
-                $(addsuffix .mk,$(toolchains)))
+                undefine CC
+        endif
+
+        ifeq ($(origin CPP),default)
+                undefine CPP
+        endif
+
+        ifeq ($(origin AS),default)
+                undefine AS
+        endif
+
+        ifeq ($(origin AR),default)
+                undefine AR
+        endif
+
+        ifeq ($(origin LD),default)
+                undefine LD
+        endif
+
+        #
+        # The full list of toolchains supported by TF-A.
+        #
+        # Each of these toolchains defines a file of the same name in the
+        # `toolchains` directory, which must configure the following variables:
+        #
+        #   - <toolchain>-name
+        #
+        #     A human-readable name for the toolchain,
+        #
+        # Additionally, for every tool class, it must also define:
+        #
+        #   - <toolchain>-<tool-class>-parameter
+        #
+        #     The command line or environment variable used to set the tool for
+        #     for the given tool class.
+        #
+        #   - <toolchain>-<tool-class>-default
+        #
+        #     The default command to use for the given tool class if the user
+        #     does not explicitly provide one, and if the command could not be
+        #     derived from the C compiler.
+        #
+        #   - <toolchain>-<tool-class>-id-default
+        #
+        #     The default tool identifier used if the tool for the given tool
+        #     class cannot be identified.
+        #
+
+        toolchains := host # Used for host targets
+        toolchains += aarch32 # Used for AArch32 targets
+        toolchains += aarch64 # Used for AArch64 targets
+        toolchains += rk3399-m0 # Used for RK3399 Cortex-M0 targets
+
+        include $(toolchains:%=$(dir $(toolchain-mk))toolchains/%.mk)
 
         #
         # Configure tool classes that we recognize.
@@ -139,37 +200,6 @@ ifndef toolchain-mk
         # Other tools
         toolchain-tools-dtc := generic-dtc # Device tree compilers
 
-        #
-        # Default tools for each toolchain.
-        #
-        # Toolchains can specify a default path to any given tool with a tool
-        # class. These values are used in the absence of user-specified values,
-        # and are configured by the makefile for each toolchain using variables
-        # of the form:
-        #
-        #   - $(toolchain)-$(tool-class)-default
-        #
-        # For example, the default C compiler for the AArch32 and AArch64
-        # toolchains could be configured with:
-        #
-        #   - aarch32-cc-default
-        #   - aarch64-cc-default
-        #
-
-        define toolchain-check-tool-class-default
-                ifndef $(1)-$(tool-class)-default
-                        $$(error no default value specified for tool class `$(2)` of toolchain `$(1)`)
-                endif
-        endef
-
-        define toolchain-check-tool-class-defaults
-                $(foreach tool-class,$(toolchain-tool-classes), \
-                        $(eval $(call toolchain-check-tool-class-default,$(1),$(tool-class))))
-        endef
-
-        $(foreach toolchain,$(toolchains), \
-                $(eval $(call toolchain-check-tool-class-defaults,$(toolchain))))
-
         #
         # Helper functions to identify toolchain tools.
         #
@@ -230,6 +260,36 @@ ifndef toolchain-mk
         toolchain-guess-tool = $(firstword $(foreach candidate,$(1), \
                 $(if $(call toolchain-guess-tool-$(candidate),$(2)),$(candidate))))
 
+        #
+        # Warn the user that a tool could not be identified.
+        #
+        # Parameters:
+        #
+        # - $1: The toolchain that the tool belongs to.
+        # - $2: The tool class that the tool belongs to.
+        #
+
+        define toolchain-warn-unrecognized
+                $(warning )
+                $(warning The configured $($(1)-name) $(toolchain-tool-class-name-$(2)) could not be identified and may not be supported:)
+                $(warning )
+                $(warning $(space)   $($(1)-$(2))$(if $($(1)-$(2)-parameter), (via `$($(1)-$(2)-parameter)`)))
+                $(warning )
+                $(warning The default $($(1)-name) $(toolchain-tool-class-name-$(2)) is:)
+                $(warning )
+                $(warning $(space)   $($(1)-$(2)-default))
+                $(warning )
+                $(warning The following tools are supported:)
+                $(warning )
+
+                $(foreach tool,$(toolchain-tools-$(2)), \
+                        $(warning $(space) - $(toolchain-tool-name-$(tool))))
+
+                $(warning )
+                $(warning The build system will treat this $(toolchain-tool-class-name-$(2)) as $(toolchain-tool-name-$($(1)-$(2)-id-default)).)
+                $(warning )
+        endef
+
         #
         # Locate and identify tools belonging to each toolchain.
         #
@@ -271,56 +331,80 @@ ifndef toolchain-mk
         toolchain-guess-gnu-gcc-od = $(shell $(1) --print-prog-name objdump 2>$(nul))
         toolchain-guess-gnu-gcc-ar = $(shell $(1) --print-prog-name ar 2>$(nul))
 
-        define toolchain-warn-unrecognized
+        #
-                $$(warning )
+        # Configure a toolchain.
-                $$(warning The configured $$($(1)-name) $$(toolchain-tool-class-name-$(2)) could not be identified and may not be supported:)
+        #
-                $$(warning )
+        # Parameters:
-                $$(warning $$(space)   $$($(1)-$(2)))
+        #
-                $$(warning )
+        #   - $1: The toolchain to configure.
-                $$(warning The default $$($(1)-name) $$(toolchain-tool-class-name-$(2)) is:)
+        #
-                $$(warning )
+        # This function iterates over all tool classes and configures them for
-                $$(warning $$(space)   $$($(1)-$(2)-default))
+        # the provided toolchain. Toolchain tools are initialized lazily and
-                $$(warning )
+        # on-demand based on the first read of the tool path or identifier
-                $$(warning The following tools are supported:)
+        # variables.
-                $$(warning )
+        #
 
-                $$(foreach tool,$$(toolchain-tools-$(2)), \
+        define toolchain-configure
-                        $$(warning $$(space) - $$(toolchain-tool-name-$$(tool))))
+                $$(foreach tool-class,$$(toolchain-tool-classes), \
-
+                        $$(eval $$(call toolchain-configure-tool,$1,$$(tool-class))))
-                $$(warning )
-                $$(warning The build system will treat this $$(toolchain-tool-class-name-$(2)) as $$(toolchain-tool-name-$$($(1)-$(2)-id-default)).)
-                $$(warning )
         endef
 
+        #
+        # Configure a specific tool within a toolchain.
+        #
+        # Parameters:
+        #
+        #   - $1: The toolchain to configure.
+        #   - $2: The tool class to configure.
+        #
+
+        define toolchain-configure-tool
+                $1-$2-configure = $\
+                        $$(eval $$(call toolchain-determine-tool,$1,$2))
+
+                #
+                # When either of the following variables are read for the first
+                # time, the appropriate tool is determined and *both* variables
+                # are overwritten with their final values.
+                #
+
+                $1-$2 = $$($1-$2-configure)$$($1-$2)
+                $1-$2-id = $$($1-$2-configure)$$($1-$2-id)
+        endef
+
+        #
+        # Determines and identifies a tool.
+        #
+        # Parameters:
+        #
+        #   - $1: The toolchain identifier.
+        #   - $2: The tool class.
+        #
+        # Tool identification happens by reading the designated tool parameter
+        # to get the user-specified command for the tool (e.g. `CC` or `LD`). If
+        # no tool parameter is defined then try to derive the tool from the C
+        # compiler.
+        #
+        # If all else fails, fall back to the default command defined by the
+        # toolchain makefile.
+        #
+
         define toolchain-determine-tool
-                $(1)-$(2)-guess = $$(if $$(filter-out cc,$(2)),$\
+                toolchain-$1-$2-guess = $$(if $$(filter-out cc,$2),$\
-                        $$(call toolchain-guess-$$($(1)-cc-id)-$(2),$$($(1)-cc)))
+                        $$(call toolchain-guess-$$($1-cc-id)-$2,$$($1-cc)))
 
-                $(1)-$(2) := $$(or $$($(1)-$(2)),$$($(1)-$(2)-guess))
+                toolchain-$1-$2-shell = $$(or $$($$($1-$2-parameter)),$\
-                $(1)-$(2) := $$(or $$($(1)-$(2)),$$($(1)-$(2)-default))
+                        $$(toolchain-$1-$2-guess),$$($1-$2-default))
 
-                ifneq ($$(call which,$$($(1)-$(2))),)
+                $1-$2 := $(if $(call which,$$(toolchain-$1-$2-shell)),$\
-                        # If we can resolve this tool to a program on the `PATH`
+                        $$(call escape-shell,$$(toolchain-$1-$2-shell)),$\
-                        # then escape it for use in a shell, which allows us to
+                        $$(toolchain-$1-$2-shell))
-                        # preserve spaces.
 
-                        $(1)-$(2) := $$(call escape-shell,$$($(1)-$(2)))
+                $1-$2-id := $$(or \
-                endif
+                        $$(call toolchain-guess-tool,$$(toolchain-tools-$2),$$($1-$2)),$\
-
+                        $$(strip $$(call toolchain-warn-unrecognized,$1,$2)$$($1-$2-id-default)))
-                $(1)-$(2)-id := $$(call toolchain-guess-tool,$$(toolchain-tools-$(2)),$$($(1)-$(2)))
-
-                ifndef $(1)-$(2)-id
-                        $(1)-$(2)-id := $$($(1)-$(2)-id-default)
-
-                        $$(eval $$(call toolchain-warn-unrecognized,$(1),$(2)))
-                endif
-        endef
-
-        define toolchain-determine
-                $$(foreach tool-class,$$(toolchain-tool-classes), \
-                        $$(eval $$(call toolchain-determine-tool,$(1),$$(tool-class))))
         endef
 
         $(foreach toolchain,$(toolchains), \
-                $(eval $(call toolchain-determine,$(toolchain))))
+                $(eval $(call toolchain-configure,$(toolchain))))
 endif

make_helpers/toolchains/aarch32.mk

@@ -6,34 +6,34 @@
 
 aarch32-name := AArch32
 
-aarch32-cc := $(if $(filter-out default,$(origin CC)),$(CC))
+aarch32-cc-parameter := CC
 aarch32-cc-default := $(or $(CROSS_COMPILE),arm-none-eabi-)gcc
 aarch32-cc-id-default := gnu-gcc
 
-aarch32-cpp := $(if $(filter-out default,$(origin CPP)),$(CPP))
+aarch32-cpp-parameter := CPP
 aarch32-cpp-default := $(or $(CROSS_COMPILE),arm-none-eabi-)gcc
 aarch32-cpp-id-default := gnu-gcc
 
-aarch32-as := $(if $(filter-out default,$(origin AS)),$(AS))
+aarch32-as-parameter := AS
 aarch32-as-default := $(or $(CROSS_COMPILE),arm-none-eabi-)gcc
 aarch32-as-id-default := gnu-gcc
 
-aarch32-ld := $(if $(filter-out default,$(origin LD)),$(LD))
+aarch32-ld-parameter := LD
 aarch32-ld-default := $(or $(CROSS_COMPILE),arm-none-eabi-)gcc
 aarch32-ld-id-default := gnu-gcc
 
-aarch32-oc := $(if $(filter-out default,$(origin OC)),$(OC))
+aarch32-oc-parameter := OC
 aarch32-oc-default := $(or $(CROSS_COMPILE),arm-none-eabi-)objcopy
 aarch32-oc-id-default := gnu-objcopy
 
-aarch32-od := $(if $(filter-out default,$(origin OD)),$(OD))
+aarch32-od-parameter := OD
 aarch32-od-default := $(or $(CROSS_COMPILE),arm-none-eabi-)objdump
 aarch32-od-id-default := gnu-objdump
 
-aarch32-ar := $(if $(filter-out default,$(origin AR)),$(AR))
+aarch32-ar-parameter := AR
 aarch32-ar-default := $(or $(CROSS_COMPILE),arm-none-eabi-)gcc-ar
 aarch32-ar-id-default := gnu-ar
 
-aarch32-dtc := $(if $(filter-out default,$(origin DTC)),$(DTC))
+aarch32-dtc-parameter := DTC
 aarch32-dtc-default := dtc
 aarch32-dtc-id-default := generic-dtc

make_helpers/toolchains/aarch64.mk

@@ -6,34 +6,34 @@
 
 aarch64-name := AArch64
 
-aarch64-cc := $(if $(filter-out default,$(origin CC)),$(CC))
+aarch64-cc-parameter := CC
 aarch64-cc-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)gcc
 aarch64-cc-id-default := gnu-gcc
 
-aarch64-cpp := $(if $(filter-out default,$(origin CPP)),$(CPP))
+aarch64-cpp-parameter := CPP
 aarch64-cpp-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)gcc
 aarch64-cpp-id-default := gnu-gcc
 
-aarch64-as := $(if $(filter-out default,$(origin AS)),$(AS))
+aarch64-as-parameter := AS
 aarch64-as-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)gcc
 aarch64-as-id-default := gnu-gcc
 
-aarch64-ld := $(if $(filter-out default,$(origin LD)),$(LD))
+aarch64-ld-parameter := LD
 aarch64-ld-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)gcc
 aarch64-ld-id-default := gnu-gcc
 
-aarch64-oc := $(if $(filter-out default,$(origin OC)),$(OC))
+aarch64-oc-parameter := OC
 aarch64-oc-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)objcopy
 aarch64-oc-id-default := gnu-objcopy
 
-aarch64-od := $(if $(filter-out default,$(origin OD)),$(OD))
+aarch64-od-parameter := OD
 aarch64-od-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)objdump
 aarch64-od-id-default := gnu-objdump
 
-aarch64-ar := $(if $(filter-out default,$(origin AR)),$(AR))
+aarch64-ar-parameter := AR
 aarch64-ar-default := $(or $(CROSS_COMPILE),aarch64-none-elf-)gcc-ar
 aarch64-ar-id-default := gnu-ar
 
-aarch64-dtc := $(if $(filter-out default,$(origin DTC)),$(DTC))
+aarch64-dtc-parameter := DTC
 aarch64-dtc-default := dtc
 aarch64-dtc-id-default := generic-dtc

make_helpers/toolchains/host.mk

@@ -6,34 +6,34 @@
 
 host-name := host
 
-host-cc := $(HOSTCC)
+host-cc-parameter := HOSTCC
 host-cc-default := gcc
 host-cc-id-default := gnu-gcc
 
-host-cpp := $(HOSTCPP)
+host-cpp-parameter := HOSTCPP
 host-cpp-default := gcc
 host-cpp-id-default := gnu-gcc
 
-host-as := $(HOSTAS)
+host-as-parameter := HOSTAS
 host-as-default := gcc
 host-as-id-default := gnu-gcc
 
-host-ld := $(HOSTLD)
+host-ld-parameter := HOSTLD
 host-ld-default := gcc
 host-ld-id-default := gnu-gcc
 
-host-oc := $(HOSTOC)
+host-oc-parameter := HOSTOC
 host-oc-default := objcopy
 host-oc-id-default := gnu-objcopy
 
-host-od := $(HOSTOD)
+host-od-parameter := HOSTOD
 host-od-default := objdump
 host-od-id-default := gnu-objdump
 
-host-ar := $(HOSTAR)
+host-ar-parameter := HOSTAR
 host-ar-default := gcc-ar
 host-ar-id-default := gnu-ar
 
-host-dtc := $(HOSTDTC)
+host-dtc-parameter := HOSTDTC
 host-dtc-default := dtc
 host-dtc-id-default := generic-dtc

plat/rockchip/rk3399/drivers/m0/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-toolchains := rk3399-m0
-
 include ../../../../../make_helpers/common.mk
 include ../../../../../make_helpers/toolchain.mk
 

tools/amlogic/Makefile

@@ -5,8 +5,6 @@
 # https://spdx.org/licenses
 #
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/cert_create/Makefile

@@ -10,8 +10,6 @@ CRTTOOL		?= cert_create${BIN_EXT}
 BINARY		:= $(notdir ${CRTTOOL})
 COT		:= tbbr
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/encrypt_fw/Makefile

@@ -11,8 +11,6 @@ ENCTOOL		?= encrypt_fw${BIN_EXT}
 BINARY		:= $(notdir ${ENCTOOL})
 OPENSSL_DIR	:= /usr
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/fiptool/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/marvell/doimage/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier:     BSD-3-Clause
 # https://spdx.org/licenses
 
-toolchains := host
-
 include ../../../make_helpers/common.mk
 include ../../../make_helpers/toolchain.mk
 

tools/nxp/create_pbl/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/sptool/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk

tools/stm32image/Makefile

@@ -4,8 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-toolchains := host
-
 MAKE_HELPERS_DIRECTORY := ../../make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk
 include ${MAKE_HELPERS_DIRECTORY}build_env.mk