diff options
| -rw-r--r-- | config/toolchain.in | 38 | ||||
| -rw-r--r-- | docs/overview.txt | 47 | ||||
| -rw-r--r-- | scripts/build/internals.sh | 22 |
3 files changed, 104 insertions, 3 deletions
diff --git a/config/toolchain.in b/config/toolchain.in index ffa4f3e..0aae112 100644 --- a/config/toolchain.in +++ b/config/toolchain.in @@ -296,4 +296,42 @@ config TARGET_SUFFIX endif # CROSS_NATIVE || CANADIAN +# Kept as a separate if block, even if it could go into the above block, +# because it seems better. No real reason, only that it seems right... +if CANADIAN + +comment "Host specifics" + +choice + bool + prompt "| Install tools wrapper as:" + default TOOLS_WRAPPER_SHELL + +config TOOLS_WRAPPER_SCRIPT + bool + prompt "shell script" + help + If your host has a shell, then you should say 'Y' here, to use + a (very very simple) shell script as wrapper. + + See docs/overview.txt, section "Tools wrapper". + +config TOOLS_WRAPPER_EXEC + bool + prompt "executable" + help + If your host lacks a shell, then you should say 'Y' here, to use + an executable. + + See docs/overview.txt, section "Tools wrapper". + +endchoice + +config TOOLS_WRAPPER + string + default "script" if TOOLS_WRAPPER_SCRIPT + default "exec" if TOOLS_WRAPPER_EXEC + +endif # CROSS_NATIVE || CANADIAN + endmenu diff --git a/docs/overview.txt b/docs/overview.txt index ed45d63..1176352 100644 --- a/docs/overview.txt +++ b/docs/overview.txt @@ -25,6 +25,7 @@ Running crosstool-NG Testing all toolchains at once Overriding the number of // jobs Note on // jobs + Tools wrapper Using the toolchain Toolchain types Internals @@ -382,6 +383,52 @@ in parallel (there is not much to gain). When speaking of // jobs, we are refering to the number of // jobs when making the *components*. That is, we speak of the number of // jobs used to build gcc, glibc, and so on... +Tools wrapper | +--------------+ + +Starting with gcc-4.3 come two new dependencies: GMP and MPFR. With gcc-4.4, +come three new ones: GMP, PPL and CLooG/ppl. These are libraries that enable +advanced features to gcc. Additionally, some of the libraries can be used by +binutils and gdb. Unfortunately, not all systems on which crosstool-NG runs +have all of those libraries. And for those that do, the versions of those +libraries may be older than the version required by gcc. + +This is why crosstool-NG builds its own set of libraries as part of the +toolchain. + +The libraries are built as shared libraries, because building them as static +libraries has some short-comings. This poses no problem at build time, as +crosstool-NG correctly points gcc (and binutiols and gdb) to the correct +place where our own version of the libraries are installed. But it poses +a problem when gcc et al. are run: the place where the libraries are is most +probably not known to the host dynamic linker. Still worse, if the host system +has its own versions, then ld.so would load the wrong library! + +So we have to force the dynamic linker to load the correct version. We do this +by using the LD_LIBRARY_PATH variable, that informs the dynamic linker where +to look for shared libraries prior to searching its standard places. But we +can't impose that burden on all the system (because it'd be a nightmare to +configure, and because two tolchains on the same system may use different +versions of the libraries); so we have to do it on a per-toolchain basis. + +So we rename all binaries of the toolchain (by adding a dot '.' as their first +character), and add a small program, the so-called "tools wrapper", that +correctly sets LD_LIBRARY_PATH prior to running the real tool. + +First, the wrapper was written as a POSIX-compliant shell script. That shell +script is very simple, if not trivial, and works great. The only drawback is +that it does not work on host systems that lack a shell, for example the +MingW32 environment. To solve the issue, the wrapper has been re-written in C, +and compiled at build time. This C wrapper is much more complex than the shell +script, and although it sems to be working, it's been only lightly tested. +Some of the expected short-comings with this C wrapper are; + - multi-byte file names may not be handled correctly + - it's really big for what it does + +So, the default wrapper installed with your toolchain is the shell script. +If you know that your system is missing a shell, then you shall use the C +wrapper (and report back whether it works, or does not work, for you). + _______________________ / diff --git a/scripts/build/internals.sh b/scripts/build/internals.sh index a920c50..cf869a1 100644 --- a/scripts/build/internals.sh +++ b/scripts/build/internals.sh @@ -46,9 +46,25 @@ do_finish() { CT_DoLog EXTRA "Installing toolchain wrappers" CT_Pushd "${CT_PREFIX_DIR}/bin" - # Copy the wrapper - CT_DoExecLog DEBUG install -m 0755 "${CT_LIB_DIR}/scripts/wrapper.in" \ - ".${CT_TARGET}-wrapper" + # Install the wrapper + case "${CT_TOOLS_WRAPPER}" in + script) + CT_DoExecLog DEBUG install \ + -m 0755 \ + "${CT_LIB_DIR}/scripts/wrapper.in" \ + ".${CT_TARGET}-wrapper" + ;; + exec) + _t="-s" + if [ "${CT_DEBUG_CT}" = "y" ]; then + _t="" # If debugging crosstool-NG, don't strip the wrapper + fi + CT_DoExecLog "${HOST_CC}" \ + -Wall -Wextra -Wunreachable-code -Werror \ + -O3 -static ${_t} \ + -o ".${CT_TARGET}-wrapper" + ;; + esac # Replace every tools with the wrapper # Do it unconditionally, even for those tools that happen to be shell |