From fe21cede3939a435d62efbd5799547fab6af1b0a Mon Sep 17 00:00:00 2001 From: Romain Naour Date: Mon, 5 Aug 2019 16:06:48 +0200 Subject: [PATCH] lib/Driver/ToolChains/Gnu: Use GCC_INSTALL_PREFIX in the set of prefixes for searching the gcc toolchain By default, the Gnu Toolchains driver is looking at the parent directory while looking for the gcc toolchain when clang is installed at "D.InstalledDir" But this doesn't work with Buildroot since the external toolchain is installed in host/opt/ext-toolchain and the sysroot is moved to host/-buildroot-linux-gnu/sysroot/ directory. We tried by setting GCC_INSTALL_PREFIX in clang.mk for host-clang but it doesn't work since we already provide a sysroot [1]. Help the Gnu Toolchains driver by using GCC_INSTALL_PREFIX path. Since we want to be able to relocate the clang toolchain, allow to use a relative path with GCC_INSTALL_PREFIX. Buildroot will provide such relative path by using: HOST_CLANG_CONF_OPTS += -DGCC_INSTALL_PREFIX:PATH=`realpath --relative-to=$(HOST_DIR)/bin/ $(TOOLCHAIN_EXTERNAL_INSTALL_DIR)` Doing so allow to use clang without providing additional search paths with -B option on the clang's command line. [1] https://reviews.llvm.org/D49244 [2] http://lists.busybox.net/pipermail/buildroot/2019-August/256204.html Signed-off-by: Romain Naour Signed-off-by: Matthew Weber --- Pending, access to llvm mailing lists to submit it is pending. They seem to be having issues with their listserv. --- lib/Driver/ToolChains/Gnu.cpp | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/lib/Driver/ToolChains/Gnu.cpp b/lib/Driver/ToolChains/Gnu.cpp index 2ad45097dc..90d6b5b748 100644 --- a/lib/Driver/ToolChains/Gnu.cpp +++ b/lib/Driver/ToolChains/Gnu.cpp @@ -1725,6 +1725,8 @@ void Generic_GCC::GCCInstallationDetector::init( Prefixes.push_back(GCCToolchainDir); } else { + StringRef GccIinstallPrefix = GCC_INSTALL_PREFIX; + // If we have a SysRoot, try that first. if (!D.SysRoot.empty()) { Prefixes.push_back(D.SysRoot); @@ -1734,6 +1736,21 @@ void Generic_GCC::GCCInstallationDetector::init( // Then look for gcc installed alongside clang. Prefixes.push_back(D.InstalledDir + "/.."); + // Use GCC_INSTALL_PREFIX if provided by the buildsystem. + if (!GccIinstallPrefix.empty()) + { + if (llvm::sys::path::is_relative(GccIinstallPrefix)) + { + // Use a relative path to gcc from clang install path. + Prefixes.push_back(D.InstalledDir + "/" + GccIinstallPrefix.str()); + } + else + { + // Hardcode the absolute path provided by GCC_INSTALL_PREFIX. + Prefixes.push_back(GCC_INSTALL_PREFIX); + } + } + // Next, look for prefix(es) that correspond to distribution-supplied gcc // installations. if (D.SysRoot.empty()) { -- 2.20.1