Merge "build: properly namespace `toolchain.mk` variables" into integration
diff --git a/make_helpers/toolchain.mk b/make_helpers/toolchain.mk
index 9a06a9c..68be6a1 100644
--- a/make_helpers/toolchain.mk
+++ b/make_helpers/toolchain.mk
@@ -33,29 +33,29 @@
         # specific role or type of tool in the toolchain.
         #
 
-        tool-classes := cc
-        tool-class-name-cc := C compiler
+        toolchain-tool-classes := cc
+        toolchain-tool-class-name-cc := C compiler
 
-        tool-classes += cpp
-        tool-class-name-cpp := C preprocessor
+        toolchain-tool-classes += cpp
+        toolchain-tool-class-name-cpp := C preprocessor
 
-        tool-classes += as
-        tool-class-name-as := assembler
+        toolchain-tool-classes += as
+        toolchain-tool-class-name-as := assembler
 
-        tool-classes += ld
-        tool-class-name-ld := linker
+        toolchain-tool-classes += ld
+        toolchain-tool-class-name-ld := linker
 
-        tool-classes += oc
-        tool-class-name-oc := object copier
+        toolchain-tool-classes += oc
+        toolchain-tool-class-name-oc := object copier
 
-        tool-classes += od
-        tool-class-name-od := object dumper
+        toolchain-tool-classes += od
+        toolchain-tool-class-name-od := object dumper
 
-        tool-classes += ar
-        tool-class-name-ar := archiver
+        toolchain-tool-classes += ar
+        toolchain-tool-class-name-ar := archiver
 
-        tool-classes += dtc
-        tool-class-name-dtc := device tree compiler
+        toolchain-tool-classes += dtc
+        toolchain-tool-class-name-dtc := device tree compiler
 
         #
         # Configure tools that we recognize.
@@ -66,53 +66,53 @@
         #
 
         # Arm® Compiler for Embedded
-        tools := arm-clang
-        tool-name-arm-clang := Arm® Compiler for Embedded `armclang`
+        toolchain-tools := arm-clang
+        toolchain-tool-name-arm-clang := Arm® Compiler for Embedded `armclang`
 
-        tools += arm-link
-        tool-name-arm-link := Arm® Compiler for Embedded `armlink`
+        toolchain-tools += arm-link
+        toolchain-tool-name-arm-link := Arm® Compiler for Embedded `armlink`
 
-        tools += arm-ar
-        tool-name-arm-ar := Arm® Compiler for Embedded `armar`
+        toolchain-tools += arm-ar
+        toolchain-tool-name-arm-ar := Arm® Compiler for Embedded `armar`
 
-        tools += arm-fromelf
-        tool-name-arm-fromelf := Arm® Compiler for Embedded `fromelf`
+        toolchain-tools += arm-fromelf
+        toolchain-tool-name-arm-fromelf := Arm® Compiler for Embedded `fromelf`
 
         # LLVM Project
-        tools += llvm-clang
-        tool-name-llvm-clang := LLVM Clang (`clang`)
+        toolchain-tools += llvm-clang
+        toolchain-tool-name-llvm-clang := LLVM Clang (`clang`)
 
-        tools += llvm-lld
-        tool-name-llvm-lld := LLVM LLD (`lld`)
+        toolchain-tools += llvm-lld
+        toolchain-tool-name-llvm-lld := LLVM LLD (`lld`)
 
-        tools += llvm-objcopy
-        tool-name-llvm-objcopy := LLVM `llvm-objcopy`
+        toolchain-tools += llvm-objcopy
+        toolchain-tool-name-llvm-objcopy := LLVM `llvm-objcopy`
 
-        tools += llvm-objdump
-        tool-name-llvm-objdump := LLVM `llvm-objdump`
+        toolchain-tools += llvm-objdump
+        toolchain-tool-name-llvm-objdump := LLVM `llvm-objdump`
 
-        tools += llvm-ar
-        tool-name-llvm-ar := LLVM `llvm-ar`
+        toolchain-tools += llvm-ar
+        toolchain-tool-name-llvm-ar := LLVM `llvm-ar`
 
         # GNU Compiler Collection & GNU Binary Utilities
-        tools += gnu-gcc
-        tool-name-gnu-gcc := GNU GCC (`gcc`)
+        toolchain-tools += gnu-gcc
+        toolchain-tool-name-gnu-gcc := GNU GCC (`gcc`)
 
-        tools += gnu-ld
-        tool-name-gnu-ld := GNU LD (`ld.bfd`)
+        toolchain-tools += gnu-ld
+        toolchain-tool-name-gnu-ld := GNU LD (`ld.bfd`)
 
-        tools += gnu-objcopy
-        tool-name-gnu-objcopy := GNU `objcopy`
+        toolchain-tools += gnu-objcopy
+        toolchain-tool-name-gnu-objcopy := GNU `objcopy`
 
-        tools += gnu-objdump
-        tool-name-gnu-objdump := GNU `objdump`
+        toolchain-tools += gnu-objdump
+        toolchain-tool-name-gnu-objdump := GNU `objdump`
 
-        tools += gnu-ar
-        tool-name-gnu-ar := GNU `ar`
+        toolchain-tools += gnu-ar
+        toolchain-tool-name-gnu-ar := GNU `ar`
 
         # Other tools
-        tools += generic-dtc
-        tool-name-generic-dtc := Device Tree Compiler (`dtc`)
+        toolchain-tools += generic-dtc
+        toolchain-tool-name-generic-dtc := Device Tree Compiler (`dtc`)
 
         #
         # Assign tools to tool classes.
@@ -120,35 +120,24 @@
         # Multifunctional tools, i.e. tools which can perform multiple roles in
         # a toolchain, may be specified in multiple tool class lists. For
         # example, a C compiler which can also perform the role of a linker may
-        # be placed in both `tools-cc` and `tools-ld`.
+        # be placed in both `toolchain-tools-cc` and `toolchain-tools-ld`.
         #
 
         # C-related tools
-        tools-cc := arm-clang llvm-clang gnu-gcc # C compilers
-        tools-cpp := arm-clang llvm-clang gnu-gcc # C preprocessors
+        toolchain-tools-cc := arm-clang llvm-clang gnu-gcc # C compilers
+        toolchain-tools-cpp := arm-clang llvm-clang gnu-gcc # C preprocessors
 
         # Assembly-related tools
-        tools-as := arm-clang llvm-clang gnu-gcc # Assemblers
+        toolchain-tools-as := arm-clang llvm-clang gnu-gcc # Assemblers
 
         # Linking and object-handling tools
-        tools-ld := arm-clang arm-link llvm-clang llvm-lld gnu-gcc gnu-ld # Linkers
-        tools-oc := arm-fromelf llvm-objcopy gnu-objcopy # Object copiers
-        tools-od := arm-fromelf llvm-objdump gnu-objdump # Object dumpers
-        tools-ar := arm-ar llvm-ar gnu-ar # Archivers
+        toolchain-tools-ld := arm-clang arm-link llvm-clang llvm-lld gnu-gcc gnu-ld # Linkers
+        toolchain-tools-oc := arm-fromelf llvm-objcopy gnu-objcopy # Object copiers
+        toolchain-tools-od := arm-fromelf llvm-objdump gnu-objdump # Object dumpers
+        toolchain-tools-ar := arm-ar llvm-ar gnu-ar # Archivers
 
         # Other tools
-        tools-dtc := generic-dtc # Device tree compilers
-
-        define check-tool-class-tools
-                $(eval tool-class := $(1))
-
-                ifndef tools-$(tool-class)
-                        $$(error no tools registered to handle tool class `$(tool-class)`)
-                endif
-        endef
-
-        $(foreach tool-class,$(tool-classes), \
-                $(eval $(call check-tool-class-tools,$(tool-class))))
+        toolchain-tools-dtc := generic-dtc # Device tree compilers
 
         #
         # Default tools for each toolchain.
@@ -167,24 +156,19 @@
         #   - aarch64-cc-default
         #
 
-        define check-toolchain-tool-class-default
-                $(eval toolchain := $(1))
-                $(eval tool-class := $(2))
-
-                ifndef $(toolchain)-$(tool-class)-default
-                        $$(error no default value specified for tool class `$(tool-class)` of toolchain `$(toolchain)`)
+        define toolchain-check-tool-class-default
+                ifndef $(1)-$(tool-class)-default
+                        $$(error no default value specified for tool class `$(2)` of toolchain `$(1)`)
                 endif
         endef
 
-        define check-toolchain-tool-class-defaults
-                $(eval toolchain := $(1))
-
-                $(foreach tool-class,$(tool-classes), \
-                        $(eval $(call check-toolchain-tool-class-default,$(toolchain),$(tool-class))))
+        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 $(call check-toolchain-tool-class-defaults,$(toolchain))))
+                $(eval $(call toolchain-check-tool-class-defaults,$(toolchain))))
 
         #
         # Helper functions to identify toolchain tools.
@@ -194,14 +178,15 @@
         # to more reliably identify tools than by looking at the path alone
         # (e.g. `gcc` on macOS is actually Apple Clang).
         #
-        # Each tool-guessing function (`guess-tool-$(tool)`) takes a single
-        # argument giving the path to the tool to guess, and returns a non-empty
-        # value if the tool corresponds to the tool identifier `$(tool)`:
+        # Each tool-guessing function (`toolchain-guess-tool-$(tool)`) takes a
+        # single argument giving the path to the tool to guess, and returns a
+        # non-empty value if the tool corresponds to the tool identifier
+        # `$(tool)`:
         #
-        #     $(call guess-tool-llvm-clang,aarch64-none-elf-gcc) # <empty>
-        #     $(call guess-tool-gnu-gcc,aarch64-none-elf-gcc) # <non-empty>
+        #     $(call toolchain-guess-tool-llvm-clang,aarch64-none-elf-gcc) # <empty>
+        #     $(call toolchain-guess-tool-gnu-gcc,aarch64-none-elf-gcc) # <non-empty>
         #
-        # The `guess-tool` function tries to find the corresponding tool
+        # The `toolchain-guess-tool` function tries to find the corresponding tool
         # identifier for a tool given its path. It takes two arguments:
         #
         #   - $(1): a list of candidate tool identifiers to check
@@ -211,39 +196,39 @@
         # identifiers return a non-empty value then the tool identifier of the
         # first function to do so is returned:
         #
-        #     $(call guess-tool,gnu-gcc llvm-clang,armclang) # <empty>
-        #     $(call guess-tool,gnu-gcc llvm-clang,clang-14) # llvm-clang
-        #     $(call guess-tool,gnu-gcc llvm-clang,aarch64-none-elf-gcc-12) # gnu-gcc
+        #     $(call toolchain-guess-tool,gnu-gcc llvm-clang,armclang) # <empty>
+        #     $(call toolchain-guess-tool,gnu-gcc llvm-clang,clang-14) # llvm-clang
+        #     $(call toolchain-guess-tool,gnu-gcc llvm-clang,aarch64-none-elf-gcc-12) # gnu-gcc
         #
-        # Tools are checked in the order that they appear in
-        # `tools-$(tool-class)`, and the first match is returned.
+        # Tools are checked in the order that they are provided, and the first
+        # match is returned.
         #
 
         # Arm Compiler for Embedded
-        guess-tool-arm-clang = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Tool: armclang")
-        guess-tool-arm-link = $(shell $(1) --help 2>&1 <$(nul) | grep -o "Tool: armlink")
-        guess-tool-arm-fromelf = $(shell $(1) --help 2>&1 <$(nul) | grep -o "Tool: fromelf")
-        guess-tool-arm-ar = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Tool: armar")
+        toolchain-guess-tool-arm-clang = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Tool: armclang")
+        toolchain-guess-tool-arm-link = $(shell $(1) --help 2>&1 <$(nul) | grep -o "Tool: armlink")
+        toolchain-guess-tool-arm-fromelf = $(shell $(1) --help 2>&1 <$(nul) | grep -o "Tool: fromelf")
+        toolchain-guess-tool-arm-ar = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Tool: armar")
 
         # LLVM Project
-        guess-tool-llvm-clang = $(shell $(1) -v 2>&1 <$(nul) | grep -o "clang version")
-        guess-tool-llvm-lld = $(shell $(1) --help 2>&1 <$(nul) | grep -o "OVERVIEW: lld")
-        guess-tool-llvm-objcopy = $(shell $(1) --help 2>&1 <$(nul) | grep -o "llvm-objcopy tool")
-        guess-tool-llvm-objdump = $(shell $(1) --help 2>&1 <$(nul) | grep -o "llvm object file dumper")
-        guess-tool-llvm-ar = $(shell $(1) --help 2>&1 <$(nul) | grep -o "LLVM Archiver")
+        toolchain-guess-tool-llvm-clang = $(shell $(1) -v 2>&1 <$(nul) | grep -o "clang version")
+        toolchain-guess-tool-llvm-lld = $(shell $(1) --help 2>&1 <$(nul) | grep -o "OVERVIEW: lld")
+        toolchain-guess-tool-llvm-objcopy = $(shell $(1) --help 2>&1 <$(nul) | grep -o "llvm-objcopy tool")
+        toolchain-guess-tool-llvm-objdump = $(shell $(1) --help 2>&1 <$(nul) | grep -o "llvm object file dumper")
+        toolchain-guess-tool-llvm-ar = $(shell $(1) --help 2>&1 <$(nul) | grep -o "LLVM Archiver")
 
         # GNU Compiler Collection & GNU Binary Utilities
-        guess-tool-gnu-gcc = $(shell $(1) -v 2>&1 <$(nul) | grep -o "gcc version")
-        guess-tool-gnu-ld = $(shell $(1) -v 2>&1 <$(nul) | grep -o "GNU ld")
-        guess-tool-gnu-objcopy = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU objcopy")
-        guess-tool-gnu-objdump = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU objdump")
-        guess-tool-gnu-ar = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU ar")
+        toolchain-guess-tool-gnu-gcc = $(shell $(1) -v 2>&1 <$(nul) | grep -o "gcc version")
+        toolchain-guess-tool-gnu-ld = $(shell $(1) -v 2>&1 <$(nul) | grep -o "GNU ld")
+        toolchain-guess-tool-gnu-objcopy = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU objcopy")
+        toolchain-guess-tool-gnu-objdump = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU objdump")
+        toolchain-guess-tool-gnu-ar = $(shell $(1) --version 2>&1 <$(nul) | grep -o "GNU ar")
 
         # Other tools
-        guess-tool-generic-dtc = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Version: DTC")
+        toolchain-guess-tool-generic-dtc = $(shell $(1) --version 2>&1 <$(nul) | grep -o "Version: DTC")
 
-        guess-tool = $(firstword $(foreach candidate,$(1), \
-                $(if $(call guess-tool-$(candidate),$(2)),$(candidate))))
+        toolchain-guess-tool = $(firstword $(foreach candidate,$(1), \
+                $(if $(call toolchain-guess-tool-$(candidate),$(2)),$(candidate))))
 
         #
         # Locate and identify tools belonging to each toolchain.
@@ -258,63 +243,58 @@
         #
         # For each of these variables, if no program path is explicitly provided
         # by the parent Makefile then the C compiler is queried (if supported)
-        # for its location. This is done via the `guess-$(tool)-$(tool-class)`
-        # set of functions. For example:
+        # for its location.
         #
-        #   - `guess-arm-clang-ld` guesses the linker via Arm Clang,
-        #   - `guess-llvm-clang-as` guesses the assembler via LLVM Clang, and
-        #   - `guess-gnu-gcc-od` guesses the object dumper via GNU GCC.
-        #
-        # If the C compiler cannot provide the location (or the tool class is
-        # the C compiler), then it is assigned the value of the
-        # `$(toolchain)-$(tool)-default` variable.
+        # If the C compiler cannot provide the location (or the tool class *is*
+        # the C compiler), then it is assigned a default value specific for that
+        # toolchain.
         #
 
-        guess-arm-clang-cpp = $(1)
-        guess-arm-clang-as = $(1)
-        guess-arm-clang-ld = # Fall back to `$(toolchain)-ld-default`
-        guess-arm-clang-oc = # Fall back to `$(toolchain)-oc-default`
-        guess-arm-clang-od = # Fall back to `$(toolchain)-od-default`
-        guess-arm-clang-ar = # Fall back to `$(toolchain)-ar-default`
+        toolchain-guess-arm-clang-cpp = $(1)
+        toolchain-guess-arm-clang-as = $(1)
+        toolchain-guess-arm-clang-ld = # Fall back to `$(toolchain)-ld-default`
+        toolchain-guess-arm-clang-oc = # Fall back to `$(toolchain)-oc-default`
+        toolchain-guess-arm-clang-od = # Fall back to `$(toolchain)-od-default`
+        toolchain-guess-arm-clang-ar = # Fall back to `$(toolchain)-ar-default`
 
-        guess-llvm-clang-cpp = $(1)
-        guess-llvm-clang-as = $(1)
-        guess-llvm-clang-ld = $(shell $(1) --print-prog-name ld.lld 2>$(nul))
-        guess-llvm-clang-oc = $(shell $(1) --print-prog-name llvm-objcopy 2>$(nul))
-        guess-llvm-clang-od = $(shell $(1) --print-prog-name llvm-objdump 2>$(nul))
-        guess-llvm-clang-ar = $(shell $(1) --print-prog-name llvm-ar 2>$(nul))
+        toolchain-guess-llvm-clang-cpp = $(1)
+        toolchain-guess-llvm-clang-as = $(1)
+        toolchain-guess-llvm-clang-ld = $(shell $(1) --print-prog-name ld.lld 2>$(nul))
+        toolchain-guess-llvm-clang-oc = $(shell $(1) --print-prog-name llvm-objcopy 2>$(nul))
+        toolchain-guess-llvm-clang-od = $(shell $(1) --print-prog-name llvm-objdump 2>$(nul))
+        toolchain-guess-llvm-clang-ar = $(shell $(1) --print-prog-name llvm-ar 2>$(nul))
 
-        guess-gnu-gcc-cpp = $(1)
-        guess-gnu-gcc-as = $(1)
-        guess-gnu-gcc-ld = $(1)
-        guess-gnu-gcc-oc = $(shell $(1) --print-prog-name objcopy 2>$(nul))
-        guess-gnu-gcc-od = $(shell $(1) --print-prog-name objdump 2>$(nul))
-        guess-gnu-gcc-ar = $(shell $(1) --print-prog-name ar 2>$(nul))
+        toolchain-guess-gnu-gcc-cpp = $(1)
+        toolchain-guess-gnu-gcc-as = $(1)
+        toolchain-guess-gnu-gcc-ld = $(1)
+        toolchain-guess-gnu-gcc-oc = $(shell $(1) --print-prog-name objcopy 2>$(nul))
+        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
                 $$(warning )
-                $$(warning The configured $$($(1)-name) $$(tool-class-name-$(2)) could not be identified and may not be supported:)
+                $$(warning The configured $$($(1)-name) $$(toolchain-tool-class-name-$(2)) could not be identified and may not be supported:)
                 $$(warning )
                 $$(warning $$(space)   $$($(1)-$(2)))
                 $$(warning )
-                $$(warning The default $$($(1)-name) $$(tool-class-name-$(2)) is:)
+                $$(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 )
 
-                $$(foreach tool,$$(tools-$(2)), \
-                        $$(warning $$(space) - $$(tool-name-$$(tool))))
+                $$(foreach tool,$$(toolchain-tools-$(2)), \
+                        $$(warning $$(space) - $$(toolchain-tool-name-$$(tool))))
 
                 $$(warning )
-                $$(warning The build system will treat this $$(tool-class-name-$(2)) as $$(tool-name-$$($(1)-$(2)-id-default)).)
+                $$(warning The build system will treat this $$(toolchain-tool-class-name-$(2)) as $$(toolchain-tool-name-$$($(1)-$(2)-id-default)).)
                 $$(warning )
         endef
 
         define toolchain-determine-tool
                 $(1)-$(2)-guess = $$(if $$(filter-out cc,$(2)),$\
-                        $$(call guess-$$($(1)-cc-id)-$(2),$$($(1)-cc)))
+                        $$(call toolchain-guess-$$($(1)-cc-id)-$(2),$$($(1)-cc)))
 
                 $(1)-$(2) := $$(or $$($(1)-$(2)),$$($(1)-$(2)-guess))
                 $(1)-$(2) := $$(or $$($(1)-$(2)),$$($(1)-$(2)-default))
@@ -322,12 +302,12 @@
                 ifneq ($$(call which,$$($(1)-$(2))),)
                         # If we can resolve this tool to a program on the `PATH`
                         # then escape it for use in a shell, which allows us to
-                        # preserve spaces.
+                        # preserve spaces.
 
                         $(1)-$(2) := $$(call escape-shell,$$($(1)-$(2)))
                 endif
 
-                $(1)-$(2)-id := $$(call guess-tool,$$(tools-$(2)),$$($(1)-$(2)))
+                $(1)-$(2)-id := $$(call toolchain-guess-tool,$$(toolchain-tools-$(2)),$$($(1)-$(2)))
 
                 ifndef $(1)-$(2)-id
                         $(1)-$(2)-id := $$($(1)-$(2)-id-default)
@@ -337,7 +317,7 @@
         endef
 
         define toolchain-determine
-                $$(foreach tool-class,$$(tool-classes), \
+                $$(foreach tool-class,$$(toolchain-tool-classes), \
                         $$(eval $$(call toolchain-determine-tool,$(1),$$(tool-class))))
         endef