Re: [PATCH] Pass PKG_CONFIG_PATH down from top-level Makefile

[Simon Marchi <simark@simark.ca>]

Hi gcc-patches,

I had applied the patch below to binutils-gdb, but it recently got wiped
out by a gcc -> binutils-gdb configure.ac sync.  Would it be possible to
apply it to the gcc repo so this doesn't happen again?

Thanks,

Simon

On 2022-03-15 17:26, Simon Marchi via Gdb-patches wrote:
> From: Simon Marchi <simon.marchi@efficios.com>
> 
> [Sending to binutils, gdb-patches and gcc-patches, since it touches the
> top-level Makefile/configure]
> 
> I have my debuginfod library installed in a non-standard location
> (/opt/debuginfod), which requires me to set
> PKG_CONFIG_PATH=/opt/debuginfod/lib/pkg-config.  If I just set it during
> configure:
> 
>     $ PKG_CONFIG_PATH=/opt/debuginfod/lib/pkg-config ./configure --with-debuginfod
>     $ make
> 
> or
> 
>     $ ./configure --with-debuginfod PKG_CONFIG_PATH=/opt/debuginfod/lib/pkg-config
>     $ make
> 
> Then PKG_CONFIG_PATH is only present (and ignored) during the top-level
> configure.  When running make (which runs gdb's and binutils'
> configure), PKG_CONFIG_PATH is not set, which results in their configure
> script not finding the library:
> 
>     checking for libdebuginfod >= 0.179... no
>     configure: error: "--with-debuginfod was given, but libdebuginfod is missing or unusable."
> 
> Change the top-level configure/Makefile system to capture the value
> passed when configuring the top-level and pass it down to
> subdirectories (similar to CFLAGS, LDFLAGS, etc).
> 
> I don't know much about the top-level build system, so I really don't
> know if I did this correctly.  The changes are:
> 
>  - Use AC_SUBST(PKG_CONFIG_PATH) in configure.ac, so that
>    @PKG_CONFIG_PATH@ gets replaced with the actual PKG_CONFIG_PATH value
>    in config files (i.e. Makefile)
>  - Add a PKG_CONFIG_PATH Makefile variable in Makefile.tpl, initialized
>    to @PKG_CONFIG_PATH@
>  - Add PKG_CONFIG_PATH to HOST_EXPORTS in Makefile.tpl, which are the
>    variables set when running the sub-configures
> 
> I initially added PKG_CONFIG_PATH to flags_to_pass, in Makefile.def, but
> I don't think it's needed.  AFAIU, this defines the flags to pass down
> when calling "make" in subdirectories.  We only need PKG_CONFIG_PATH to
> be passed down during configure.  After that, it's captured in
> gdb/config.status, so even if a "make" causes a re-configure later
> (because gdb/configure has changed, for example), the PKG_CONFIG_PATH
> value will be remembered.
> 
> ChangeLog:
> 
> 	* configure.ac: Add AC_SUBST(PKG_CONFIG_PATH).
> 	* configure: Re-generate.
> 	* Makefile.tpl (HOST_EXPORTS): Pass PKG_CONFIG_PATH.
> 	(PKG_CONFIG_PATH): New.
> 	* Makefile.in: Re-generate.
> 
> Change-Id: I91138dfca41c43b05e53e445f62e4b27882536bf
> ---
>  Makefile.in  | 3 +++
>  Makefile.tpl | 3 +++
>  configure    | 2 ++
>  configure.ac | 1 +
>  4 files changed, 9 insertions(+)
> 
> diff --git a/Makefile.in b/Makefile.in
> index 3aacd2daac9c..cb39e4790d69 100644
> --- a/Makefile.in
> +++ b/Makefile.in
> @@ -218,6 +218,7 @@ HOST_EXPORTS = \
>  	OBJCOPY="$(OBJCOPY)"; export OBJCOPY; \
>  	OBJDUMP="$(OBJDUMP)"; export OBJDUMP; \
>  	OTOOL="$(OTOOL)"; export OTOOL; \
> +	PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)"; export PKG_CONFIG_PATH; \
>  	READELF="$(READELF)"; export READELF; \
>  	AR_FOR_TARGET="$(AR_FOR_TARGET)"; export AR_FOR_TARGET; \
>  	AS_FOR_TARGET="$(AS_FOR_TARGET)"; export AS_FOR_TARGET; \
> @@ -444,6 +445,8 @@ LIBCXXFLAGS = $(CXXFLAGS) -fno-implicit-templates
>  GOCFLAGS = $(CFLAGS)
>  GDCFLAGS = $(CFLAGS)
>  
> +PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
> +
>  # Pass additional PGO and LTO compiler options to the PGO build.
>  BUILD_CFLAGS = $(PGO_BUILD_CFLAGS) $(PGO_BUILD_LTO_CFLAGS)
>  override CFLAGS += $(BUILD_CFLAGS)
> diff --git a/Makefile.tpl b/Makefile.tpl
> index 9df77788345a..88db8f44d53f 100644
> --- a/Makefile.tpl
> +++ b/Makefile.tpl
> @@ -221,6 +221,7 @@ HOST_EXPORTS = \
>  	OBJCOPY="$(OBJCOPY)"; export OBJCOPY; \
>  	OBJDUMP="$(OBJDUMP)"; export OBJDUMP; \
>  	OTOOL="$(OTOOL)"; export OTOOL; \
> +	PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)"; export PKG_CONFIG_PATH; \
>  	READELF="$(READELF)"; export READELF; \
>  	AR_FOR_TARGET="$(AR_FOR_TARGET)"; export AR_FOR_TARGET; \
>  	AS_FOR_TARGET="$(AS_FOR_TARGET)"; export AS_FOR_TARGET; \
> @@ -447,6 +448,8 @@ LIBCXXFLAGS = $(CXXFLAGS) -fno-implicit-templates
>  GOCFLAGS = $(CFLAGS)
>  GDCFLAGS = $(CFLAGS)
>  
> +PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
> +
>  # Pass additional PGO and LTO compiler options to the PGO build.
>  BUILD_CFLAGS = $(PGO_BUILD_CFLAGS) $(PGO_BUILD_LTO_CFLAGS)
>  override CFLAGS += $(BUILD_CFLAGS)
> diff --git a/configure b/configure
> index 26935ebda249..1badcb314f8f 100755
> --- a/configure
> +++ b/configure
> @@ -618,6 +618,7 @@ CXX_FOR_TARGET
>  CC_FOR_TARGET
>  RANLIB_PLUGIN_OPTION
>  AR_PLUGIN_OPTION
> +PKG_CONFIG_PATH
>  READELF
>  OBJDUMP
>  OBJCOPY
> @@ -10310,6 +10311,7 @@ fi
>  
>  
>  
> +
>  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -plugin option" >&5
>  $as_echo_n "checking for -plugin option... " >&6; }
>  
> diff --git a/configure.ac b/configure.ac
> index da4e41d72479..5b6e20485143 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -3465,6 +3465,7 @@ AC_SUBST(CC)
>  AC_SUBST(CXX)
>  AC_SUBST(CFLAGS)
>  AC_SUBST(CXXFLAGS)
> +AC_SUBST(PKG_CONFIG_PATH)
>  
>  GCC_PLUGIN_OPTION(PLUGIN_OPTION)
>  AR_PLUGIN_OPTION=
> 
> base-commit: 6aa03e9c1769c8d925f4d23d72af93483bfd31f3