Internal toolchain wrapper & ccache support

index 342f13e..6efc013 100644
@@ -153,15 +153,14 @@ TOOLCHAIN_EXTERNAL_CROSS = $(TOOLCHAIN_EXTERNAL_BIN)/$(TOOLCHAIN_EXTERNAL_PREFIX
 TOOLCHAIN_EXTERNAL_CC = $(TOOLCHAIN_EXTERNAL_CROSS)gcc
 TOOLCHAIN_EXTERNAL_CXX = $(TOOLCHAIN_EXTERNAL_CROSS)g++
 TOOLCHAIN_EXTERNAL_READELF = $(TOOLCHAIN_EXTERNAL_CROSS)readelf
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS = -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
 
 ifeq ($(filter $(HOST_DIR)/%,$(TOOLCHAIN_EXTERNAL_BIN)),)
 # TOOLCHAIN_EXTERNAL_BIN points outside HOST_DIR => absolute path
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += \
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += \
 	-DBR_CROSS_PATH_ABS='"$(TOOLCHAIN_EXTERNAL_BIN)"'
 else
 # TOOLCHAIN_EXTERNAL_BIN points inside HOST_DIR => relative path
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += \
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += \
 	-DBR_CROSS_PATH_REL='"$(TOOLCHAIN_EXTERNAL_BIN:$(HOST_DIR)/%=%)"'
 endif
 

@@ -180,59 +179,54 @@ CC_TARGET_MODE_ := $(call qstrip,$(BR2_GCC_TARGET_MODE))
 # to select the right multilib variant
 ifeq ($(BR2_x86_64),y)
 TOOLCHAIN_EXTERNAL_CFLAGS += -m64
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_64
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_64
 endif
 ifneq ($(CC_TARGET_ARCH_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -march=$(CC_TARGET_ARCH_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ARCH='"$(CC_TARGET_ARCH_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_ARCH='"$(CC_TARGET_ARCH_)"'
 endif
 ifneq ($(CC_TARGET_CPU_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -mcpu=$(CC_TARGET_CPU_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_CPU='"$(CC_TARGET_CPU_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_CPU='"$(CC_TARGET_CPU_)"'
 endif
 ifneq ($(CC_TARGET_ABI_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -mabi=$(CC_TARGET_ABI_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ABI='"$(CC_TARGET_ABI_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_ABI='"$(CC_TARGET_ABI_)"'
 endif
 ifneq ($(CC_TARGET_FPU_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -mfpu=$(CC_TARGET_FPU_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_FPU='"$(CC_TARGET_FPU_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_FPU='"$(CC_TARGET_FPU_)"'
 endif
 ifneq ($(CC_TARGET_FLOAT_ABI_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -mfloat-abi=$(CC_TARGET_FLOAT_ABI_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_FLOAT_ABI='"$(CC_TARGET_FLOAT_ABI_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_FLOAT_ABI='"$(CC_TARGET_FLOAT_ABI_)"'
 endif
 ifneq ($(CC_TARGET_MODE_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -m$(CC_TARGET_MODE_)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_MODE='"$(CC_TARGET_MODE_)"'
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_MODE='"$(CC_TARGET_MODE_)"'
 endif
 ifeq ($(BR2_BINFMT_FLAT),y)
 TOOLCHAIN_EXTERNAL_CFLAGS += -Wl,-elf2flt
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_BINFMT_FLAT
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_BINFMT_FLAT
 endif
 ifeq ($(BR2_mipsel)$(BR2_mips64el),y)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_MIPS_TARGET_LITTLE_ENDIAN
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_MIPS_TARGET_LITTLE_ENDIAN
 TOOLCHAIN_EXTERNAL_CFLAGS += -EL
 endif
 ifeq ($(BR2_mips)$(BR2_mips64),y)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_MIPS_TARGET_BIG_ENDIAN
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_MIPS_TARGET_BIG_ENDIAN
 TOOLCHAIN_EXTERNAL_CFLAGS += -EB
 endif
 ifeq ($(BR2_arceb),y)
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ARC_TARGET_BIG_ENDIAN
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_ARC_TARGET_BIG_ENDIAN
 TOOLCHAIN_EXTERNAL_CFLAGS += -EB
 endif
-ifneq ($(BR2_TARGET_OPTIMIZATION),)
+
 TOOLCHAIN_EXTERNAL_CFLAGS += $(call qstrip,$(BR2_TARGET_OPTIMIZATION))
-# We create a list like '"-mfoo", "-mbar", "-mbarfoo"' so that each
-# flag is a separate argument when used in execv() by the external
-# toolchain wrapper.
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)",)'
-endif
 
 ifeq ($(BR2_SOFT_FLOAT),y)
 TOOLCHAIN_EXTERNAL_CFLAGS += -msoft-float
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_SOFTFLOAT=1
+TOOLCHAIN_EXTERNAL_TOOLCHAIN_WRAPPER_ARGS += -DBR_SOFTFLOAT=1
 endif
 
 # The Linaro ARMhf toolchain expects the libraries in

@@ -688,15 +682,6 @@ define TOOLCHAIN_EXTERNAL_INSTALL_BFIN_FLAT
 endef
 endif
 
-# We use --hash-style=both to increase the compatibility of
-# the generated binary with older platforms, except for MIPS,
-# where the only acceptable hash style is 'sysv'
-ifeq ($(findstring mips,$(HOSTARCH)),mips)
-TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE = sysv
-else
-TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE = both
-endif
-
 # Build toolchain wrapper for preprocessor, C and C++ compiler and setup
 # symlinks for everything else. Skip gdb symlink when we are building our
 # own gdb to prevent two gdb's in output/host/usr/bin.

@@ -707,8 +692,6 @@ endif
 # match the *cc-* pattern. Therefore, an additional case is added for *-ar,
 # *-ranlib and *-nm.
 define TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER
-	$(Q)$(call MESSAGE,"Building ext-toolchain wrapper")
-	$(Q)mkdir -p $(HOST_DIR)/usr/bin
 	$(Q)cd $(HOST_DIR)/usr/bin; \
 	for i in $(TOOLCHAIN_EXTERNAL_CROSS)*; do \
 		base=$${i##*/}; \

@@ -717,7 +700,7 @@ define TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER
 			ln -sf $$(echo $$i | sed 's%^$(HOST_DIR)%../..%') .; \
 			;; \
 		*cc|*cc-*|*++|*++-*|*cpp) \
-			ln -sf ext-toolchain-wrapper $$base; \
+			ln -sf toolchain-wrapper $$base; \
 			;; \
 		*gdb|*gdbtui) \
 			if test "$(BR2_PACKAGE_HOST_GDB)" != "y"; then \

@@ -729,10 +712,6 @@ define TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER
 			;; \
 		esac; \
 	done
-	$(HOSTCC) $(HOST_CFLAGS) $(TOOLCHAIN_EXTERNAL_WRAPPER_ARGS) \
-		-s -Wl,--hash-style=$(TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE) \
-		toolchain/toolchain-external/ext-toolchain-wrapper.c \
-		-o $(HOST_DIR)/usr/bin/ext-toolchain-wrapper
 endef
 
 # This sed magic is taken from Linux headers_install.sh script.

@@ -771,6 +750,8 @@ define TOOLCHAIN_EXTERNAL_FIXUP_UCLIBCNG_LDSO
 	fi
 endef
 
+TOOLCHAIN_EXTERNAL_BUILD_CMDS = $(TOOLCHAIN_BUILD_WRAPPER)
+
 define TOOLCHAIN_EXTERNAL_INSTALL_STAGING_CMDS
 	$(TOOLCHAIN_EXTERNAL_INSTALL_SYSROOT_LIBS)
 	$(TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER)

new file mode 100644
index 0000000..899947d
@@ -0,0 +1,26 @@
+# This file contains the definition of the toolchain wrapper build commands
+
+# We use --hash-style=both to increase the compatibility of the generated
+# binary with older platforms, except for MIPS, where the only acceptable
+# hash style is 'sysv'
+ifeq ($(findstring mips,$(HOSTARCH)),mips)
+TOOLCHAIN_WRAPPER_HASH_STYLE = sysv
+else
+TOOLCHAIN_WRAPPER_HASH_STYLE = both
+endif
+
+TOOLCHAIN_WRAPPER_ARGS = $($(PKG)_TOOLCHAIN_WRAPPER_ARGS)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
+
+# We create a list like '"-mfoo", "-mbar", "-mbarfoo"' so that each flag is a
+# separate argument when used in execv() by the toolchain wrapper.
+TOOLCHAIN_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)",)'
+
+# For simplicity, build directly into the install location
+define TOOLCHAIN_BUILD_WRAPPER
+	$(Q)mkdir -p $(HOST_DIR)/usr/bin
+	$(HOSTCC) $(HOST_CFLAGS) $(TOOLCHAIN_WRAPPER_ARGS) \
+		-s -Wl,--hash-style=$(TOOLCHAIN_WRAPPER_HASH_STYLE) \
+		toolchain/toolchain-wrapper.c \
+		-o $(HOST_DIR)/usr/bin/toolchain-wrapper
+endef

index 3426ba4..2c16fdf 100644
@@ -96,14 +96,11 @@ endef
 
 HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_FINAL_CREATE_CC_SYMLINKS
 
-# Create <arch>-linux-<tool> symlinks
-define HOST_GCC_FINAL_CREATE_SIMPLE_SYMLINKS
-	(cd $(HOST_DIR)/usr/bin; for i in $(GNU_TARGET_NAME)-*; do \
-		ln -snf $$i $(ARCH)-linux$${i##$(GNU_TARGET_NAME)}; \
-	done)
-endef
-
-HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_FINAL_CREATE_SIMPLE_SYMLINKS
+HOST_GCC_FINAL_TOOLCHAIN_WRAPPER_ARGS += $(HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS)
+HOST_GCC_FINAL_POST_BUILD_HOOKS += TOOLCHAIN_BUILD_WRAPPER
+# Note: this must be done after CREATE_CC_SYMLINKS, otherwise the
+# -cc symlink to the wrapper is not created.
+HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_INSTALL_WRAPPER_AND_SIMPLE_SYMLINKS
 
 # In gcc 4.7.x, the ARM EABIhf library loader path for (e)glibc was not
 # correct, so we create a symbolic link to make things work

index 6bb7997..4b03e47 100644
@@ -62,4 +62,8 @@ HOST_GCC_INITIAL_MAKE_OPTS += all-target-libgcc
 HOST_GCC_INITIAL_INSTALL_OPTS += install-target-libgcc
 endif
 
+HOST_GCC_INITIAL_TOOLCHAIN_WRAPPER_ARGS += $(HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS)
+HOST_GCC_INITIAL_POST_BUILD_HOOKS += TOOLCHAIN_BUILD_WRAPPER
+HOST_GCC_INITIAL_POST_INSTALL_HOOKS += HOST_GCC_INSTALL_WRAPPER_AND_SIMPLE_SYMLINKS
+
 $(eval $(host-autotools-package))

index 501fcea..b9da398 100644
@@ -235,4 +235,38 @@ HOST_GCC_COMMON_CONF_OPTS += \
 	--with-long-double-128
 endif
 
+HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CROSS_PATH_SUFFIX='".real"'
+
+# The LTO support in gcc creates wrappers for ar, ranlib and nm which load
+# the lto plugin. These wrappers are called *-gcc-ar, *-gcc-ranlib, and
+# *-gcc-nm and should be used instead of the real programs when -flto is
+# used. However, we should not add the toolchain wrapper for them, and they
+# match the *cc-* pattern. Therefore, an additional case is added for *-ar,
+# *-ranlib and *-nm.
+# Avoid that a .real is symlinked a second time.
+# Also create <arch>-linux-<tool> symlinks.
+define HOST_GCC_INSTALL_WRAPPER_AND_SIMPLE_SYMLINKS
+	$(Q)cd $(HOST_DIR)/usr/bin; \
+	for i in $(GNU_TARGET_NAME)-*; do \
+		case "$$i" in \
+		*.real) \
+			;; \
+		*-ar|*-ranlib|*-nm) \
+			ln -snf $$i $(ARCH)-linux$${i##$(GNU_TARGET_NAME)}; \
+			;; \
+		*cc|*cc-*|*++|*++-*|*cpp) \
+			rm -f $$i.real; \
+			mv $$i $$i.real; \
+			ln -sf toolchain-wrapper $$i; \
+			ln -sf toolchain-wrapper $(ARCH)-linux$${i##$(GNU_TARGET_NAME)}; \
+			ln -snf $$i.real $(ARCH)-linux$${i##$(GNU_TARGET_NAME)}.real; \
+			;; \
+		*) \
+			ln -snf $$i $(ARCH)-linux$${i##$(GNU_TARGET_NAME)}; \
+			;; \
+		esac; \
+	done
+
+endef
+
 include $(sort $(wildcard package/gcc/*/*.mk))

deleted file mode 100644
index bc2d5c6..0000000
@@ -1,207 +0,0 @@
-From 160397ef3c3331099af028f1b8d3e085b07d88ad Mon Sep 17 00:00:00 2001
-From: Khem Raj <[email protected]>
-Date: Fri, 29 Mar 2013 08:59:00 +0400
-Subject: [PATCH 16/35] gcc: poison-system-directories
-
-Adapted to Buildroot and gcc 4.7.4 by Thomas Petazzoni, especially the
-addition of the BR_COMPILER_PARANOID_UNSAFE_PATH environment variable.
-
-Signed-off-by: Khem Raj <[email protected]>
-Signed-off-by: Thomas Petazzoni <[email protected]>
-
-Upstream-Status: Inappropriate [distribution: codesourcery]
----
- gcc/Makefile.in     |    2 +-
- gcc/common.opt      |    4 ++++
- gcc/config.in       |    6 ++++++
- gcc/configure       |   20 ++++++++++++++++++--
- gcc/configure.ac    |   10 ++++++++++
- gcc/doc/invoke.texi |    9 +++++++++
- gcc/gcc.c           |    2 ++
- gcc/incpath.c       |   19 +++++++++++++++++++
- 8 files changed, 69 insertions(+), 3 deletions(-)
-
-Index: b/gcc/common.opt
-===================================================================
---- a/gcc/common.opt
-+++ b/gcc/common.opt
-@@ -585,6 +585,10 @@
- Common Var(warn_padded) Warning
- Warn when padding is required to align structure members
- 
-+Wpoison-system-directories
-+Common Var(flag_poison_system_directories) Init(1) Warning
-+Warn for -I and -L options using system directories if cross compiling
-+
- Wshadow
- Common Var(warn_shadow) Warning
- Warn when one local variable shadows another
-Index: b/gcc/config.in
-===================================================================
---- a/gcc/config.in
-+++ b/gcc/config.in
-@@ -144,6 +144,12 @@
- #endif
- 
- 
-+/* Define to warn for use of native system header directories */
-+#ifndef USED_FOR_TARGET
-+#undef ENABLE_POISON_SYSTEM_DIRECTORIES
-+#endif
-+
-+
- /* Define if you want all operations on RTL (the basic data structure of the
-    optimizer and back end) to be checked for dynamic type safety at runtime.
-    This is quite expensive. */
-Index: b/gcc/configure
-===================================================================
---- a/gcc/configure
-+++ b/gcc/configure
-@@ -918,6 +918,7 @@
- with_system_zlib
- enable_maintainer_mode
- enable_version_specific_runtime_libs
-+enable_poison_system_directories
- enable_plugin
- enable_libquadmath_support
- with_linker_hash_style
-@@ -1632,6 +1633,8 @@
-   --enable-version-specific-runtime-libs
-                           specify that runtime libraries should be installed
-                           in a compiler-specific directory
-+  --enable-poison-system-directories
-+                          warn for use of native system header directories
-   --enable-plugin         enable plugin support
-   --disable-libquadmath-support
-                           disable libquadmath support for Fortran
-@@ -27186,6 +27189,19 @@
- fi
- 
- 
-+# Check whether --enable-poison-system-directories was given.
-+if test "${enable_poison_system_directories+set}" = set; then :
-+  enableval=$enable_poison_system_directories;
-+else
-+  enable_poison_system_directories=no
-+fi
-+
-+if test "x${enable_poison_system_directories}" = "xyes"; then
-+
-+$as_echo "#define ENABLE_POISON_SYSTEM_DIRECTORIES 1" >>confdefs.h
-+
-+fi
-+
- # Substitute configuration variables
- 
- 
-Index: b/gcc/configure.ac
-===================================================================
---- a/gcc/configure.ac
-+++ b/gcc/configure.ac
-@@ -5037,6 +5037,16 @@
-                 [specify that runtime libraries should be
-                  installed in a compiler-specific directory])])
- 
-+AC_ARG_ENABLE([poison-system-directories],
-+             AS_HELP_STRING([--enable-poison-system-directories],
-+                            [warn for use of native system header directories]),,
-+             [enable_poison_system_directories=no])
-+if test "x${enable_poison_system_directories}" = "xyes"; then
-+  AC_DEFINE([ENABLE_POISON_SYSTEM_DIRECTORIES],
-+           [1],
-+           [Define to warn for use of native system header directories])
-+fi
-+
- # Substitute configuration variables
- AC_SUBST(subdirs)
- AC_SUBST(srcdir)
-Index: b/gcc/doc/invoke.texi
-===================================================================
---- a/gcc/doc/invoke.texi
-+++ b/gcc/doc/invoke.texi
-@@ -260,6 +260,7 @@
- -Woverlength-strings  -Wpacked  -Wpacked-bitfield-compat  -Wpadded @gol
- -Wparentheses  -Wpedantic-ms-format -Wno-pedantic-ms-format @gol
- -Wpointer-arith  -Wno-pointer-to-int-cast @gol
-+-Wno-poison-system-directories @gol
- -Wredundant-decls @gol
- -Wreturn-type  -Wsequence-point  -Wshadow @gol
- -Wsign-compare  -Wsign-conversion  -Wstack-protector @gol
-@@ -3880,6 +3881,14 @@
-  for most targets, it is made up of code and thus requires the stack
-  to be made executable in order for the program to work properly.
- 
-+ at item -Wno-poison-system-directories
-+ at opindex Wno-poison-system-directories
-+Do not warn for @option{-I} or @option{-L} options using system
-+directories such as @file{/usr/include} when cross compiling.  This
-+option is intended for use in chroot environments when such
-+directories contain the correct headers and libraries for the target
-+system rather than the host.
-+
- @item -Wfloat-equal
- @opindex Wfloat-equal
- @opindex Wno-float-equal
-Index: b/gcc/gcc.c
-===================================================================
---- a/gcc/gcc.c
-+++ b/gcc/gcc.c
-@@ -674,6 +674,8 @@
-     %{flto} %{flto=*} %l " LINK_PIE_SPEC \
-    "%X %{o*} %{e*} %{N} %{n} %{r}\
-     %{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!nostartfiles:%S}}\
-+    %{Wno-poison-system-directories:--no-poison-system-directories}\
-+    %{Werror=poison-system-directories:--error-poison-system-directories}\
-     %{static:} %{L*} %(mfwrap) %(link_libgcc) %o\
-     %{fopenmp|ftree-parallelize-loops=*:%:include(libgomp.spec)%(link_gomp)}\
-     %{fgnu-tm:%:include(libitm.spec)%(link_itm)}\
-@@ -3907,6 +3909,12 @@
-       gcc_assert (!compare_debug_opt);
-     }
- 
-+  temp = getenv("BR_COMPILER_PARANOID_UNSAFE_PATH");
-+  if (temp && strlen(temp) > 0)
-+    {
-+      save_switch("-Werror=poison-system-directories", 0, NULL, false);
-+    }
-+
-   /* Set up the search paths.  We add directories that we expect to
-      contain GNU Toolchain components before directories specified by
-      the machine description so that we will find GNU components (like
-Index: b/gcc/incpath.c
-===================================================================
---- a/gcc/incpath.c
-+++ b/gcc/incpath.c
-@@ -30,6 +30,7 @@
- #include "intl.h"
- #include "incpath.h"
- #include "cppdefault.h"
-+#include "diagnostic-core.h"
- 
- /* Microsoft Windows does not natively support inodes.
-    VMS has non-numeric inodes.  */
-@@ -373,6 +374,24 @@
- 	}
-       fprintf (stderr, _("End of search list.\n"));
-     }
-+
-+#ifdef ENABLE_POISON_SYSTEM_DIRECTORIES
-+  if (flag_poison_system_directories)
-+    {
-+       struct cpp_dir *p;
-+
-+       for (p = heads[QUOTE]; p; p = p->next)
-+         {
-+          if ((!strncmp (p->name, "/usr/include", 12))
-+              || (!strncmp (p->name, "/usr/local/include", 18))
-+              || (!strncmp (p->name, "/usr/X11R6/include", 18)))
-+            warning (OPT_Wpoison_system_directories,
-+                     "include location \"%s\" is unsafe for "
-+                     "cross-compilation",
-+                     p->name);
-+         }
-+    }
-+#endif
- }
- 
- /* Use given -I paths for #include "..." but not #include <...>, and

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index 2c16fdf..a5be3c7 100644
@@ -50,7 +50,6 @@ GCC_FINAL_CROSS_LANGUAGES = $(subst $(space),$(comma),$(GCC_FINAL_CROSS_LANGUAGE
 HOST_GCC_FINAL_CONF_OPTS = \
 	$(HOST_GCC_COMMON_CONF_OPTS) \
 	--enable-languages=$(GCC_FINAL_CROSS_LANGUAGES) \
-	--enable-poison-system-directories \
 	--with-build-time-tools=$(HOST_DIR)/usr/$(GNU_TARGET_NAME)/bin
 
 HOST_GCC_FINAL_GCC_LIB_DIR = $(HOST_DIR)/usr/$(GNU_TARGET_NAME)/lib*

index 545694f..4b1ce7f 100644
@@ -189,11 +189,6 @@ TARGET_OBJDUMP  = $(TARGET_CROSS)objdump
 TARGET_CC_NOCCACHE  := $(TARGET_CC)
 TARGET_CXX_NOCCACHE := $(TARGET_CXX)
 
-ifeq ($(BR2_CCACHE),y)
-TARGET_CC  := $(CCACHE) $(TARGET_CC)
-TARGET_CXX := $(CCACHE) $(TARGET_CXX)
-endif
-
 ifeq ($(BR2_STRIP_strip),y)
 STRIP_STRIP_DEBUG := --strip-debug
 STRIP_STRIP_UNNEEDED := --strip-unneeded

index 899947d..0fd2b86 100644
@@ -16,6 +16,10 @@ TOOLCHAIN_WRAPPER_ARGS += -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
 # separate argument when used in execv() by the toolchain wrapper.
 TOOLCHAIN_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)",)'
 
+ifeq ($(BR2_CCACHE),y)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE='"$(CCACHE)"'
+endif
+
 # For simplicity, build directly into the install location
 define TOOLCHAIN_BUILD_WRAPPER
 	$(Q)mkdir -p $(HOST_DIR)/usr/bin

index 545694f..4b1ce7f 100644
@@ -189,11 +189,6 @@ TARGET_OBJDUMP  = $(TARGET_CROSS)objdump
 TARGET_CC_NOCCACHE  := $(TARGET_CC)
 TARGET_CXX_NOCCACHE := $(TARGET_CXX)
 
-ifeq ($(BR2_CCACHE),y)
-TARGET_CC  := $(CCACHE) $(TARGET_CC)
-TARGET_CXX := $(CCACHE) $(TARGET_CXX)
-endif
-
 ifeq ($(BR2_STRIP_strip),y)
 STRIP_STRIP_DEBUG := --strip-debug
 STRIP_STRIP_UNNEEDED := --strip-unneeded

index 899947d..749afd7 100644
@@ -16,6 +16,10 @@ TOOLCHAIN_WRAPPER_ARGS += -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
 # separate argument when used in execv() by the toolchain wrapper.
 TOOLCHAIN_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)",)'
 
+ifeq ($(BR2_CCACHE),y)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE
+endif
+
 # For simplicity, build directly into the install location
 define TOOLCHAIN_BUILD_WRAPPER
 	$(Q)mkdir -p $(HOST_DIR)/usr/bin

index b9f90e4..7192700 100644
@@ -45,13 +45,12 @@ PERL_DEPENDENCIES += gdbm
 endif
 
 # We have to override LD, because an external multilib toolchain ld is not
-# wrapped to provide the required sysroot options.  We also can't use ccache
-# because the configure script doesn't support it.
+# wrapped to provide the required sysroot options.
 PERL_CONF_OPTS = \
 	--target=$(GNU_TARGET_NAME) \
 	--target-tools-prefix=$(TARGET_CROSS) \
 	--prefix=/usr \
-	-Dld="$(TARGET_CC_NOCCACHE)" \
+	-Dld="$(TARGET_CC)" \
 	-Dccflags="$(TARGET_CFLAGS)" \
 	-Dldflags="$(TARGET_LDFLAGS) -lm" \
 	-Dmydomain="" \

index 92739a8..7046580 100644
@@ -21,7 +21,7 @@ IMX_LIB_INCLUDE = \
 IMX_LIB_MAKE_ENV = \
 	$(TARGET_MAKE_ENV) \
 	$(TARGET_CONFIGURE_OPTS) \
-	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
+	CROSS_COMPILE="$(TARGET_CROSS)" \
 	PLATFORM=$(BR2_PACKAGE_FREESCALE_IMX_PLATFORM) \
 	INCLUDE="$(IMX_LIB_INCLUDE)"
 

index 3606857..571cc40 100644
@@ -13,7 +13,7 @@ IMX_VPU_INSTALL_STAGING = YES
 IMX_VPU_MAKE_ENV = \
 	$(TARGET_MAKE_ENV) \
 	$(TARGET_CONFIGURE_OPTS) \
-	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
+	CROSS_COMPILE="$(TARGET_CROSS)" \
 	PLATFORM=$(BR2_PACKAGE_FREESCALE_IMX_PLATFORM)
 
 IMX_VPU_LICENSE = Freescale Semiconductor Software License Agreement

index bbcc54b..2319576 100644
@@ -67,7 +67,7 @@ LINUX_MAKE_FLAGS = \
 	HOSTCFLAGS="$(HOSTCFLAGS)" \
 	ARCH=$(KERNEL_ARCH) \
 	INSTALL_MOD_PATH=$(TARGET_DIR) \
-	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
+	CROSS_COMPILE="$(TARGET_CROSS)" \
 	DEPMOD=$(HOST_DIR)/sbin/depmod
 
 LINUX_MAKE_ENV = \

index 8f321ac..7494078 100644
@@ -74,7 +74,7 @@ endif
 UBOOT_ARCH = $(KERNEL_ARCH)
 
 UBOOT_MAKE_OPTS += \
-	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
+	CROSS_COMPILE="$(TARGET_CROSS)" \
 	ARCH=$(UBOOT_ARCH)
 
 # Helper function to fill the U-Boot config.h file.

index e45976d..00e1537 100644
@@ -52,8 +52,7 @@ else
 BAREBOX_ARCH = $(KERNEL_ARCH)
 endif
 
-BAREBOX_MAKE_FLAGS = ARCH=$(BAREBOX_ARCH) CROSS_COMPILE="$(CCACHE) \
-	$(TARGET_CROSS)"
+BAREBOX_MAKE_FLAGS = ARCH=$(BAREBOX_ARCH) CROSS_COMPILE="$(TARGET_CROSS)"
 BAREBOX_MAKE_ENV = $(TARGET_MAKE_ENV)
 
 ifeq ($(BR2_TARGET_BAREBOX_USE_DEFCONFIG),y)

deleted file mode 100644
index 058fb43..0000000
@@ -1,20 +0,0 @@
-Fix compilation with ccache enabled
-
-When ccache is enabled the CROSS_COMPILE variable contains a space, so
-it must be properly quoted.
-
-Signed-off-by: Doug Kehn <[email protected]>
-
-Index: cryptodev-linux-1.7/Makefile
-===================================================================
---- cryptodev-linux-1.7.orig/Makefile
-+++ cryptodev-linux-1.7/Makefile
-@@ -18,7 +18,7 @@ ifneq (${ARCH},)
- KERNEL_MAKE_OPTS += ARCH=${ARCH}
- endif
- ifneq (${CROSS_COMPILE},)
--KERNEL_MAKE_OPTS += CROSS_COMPILE=${CROSS_COMPILE}
-+KERNEL_MAKE_OPTS += CROSS_COMPILE="${CROSS_COMPILE}"
- endif
- 
- build: version.h

index 09c1b67..adeabdf 100644
@@ -9,6 +9,8 @@ allows us to easily pass the cross-compiler paths and flags from our
 qt5.mk.
 
 Signed-off-by: Thomas Petazzoni <[email protected]>
+[Arnout: remove ccache support]
+Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <[email protected]>
 
 Index: b/mkspecs/devices/linux-buildroot-g++/qmake.conf
 ===================================================================

@@ -18,8 +20,8 @@ Index: b/mkspecs/devices/linux-buildroot-g++/qmake.conf
 +include(../common/linux_device_pre.conf)
 +
 +# modifications to g++-unix.conf
-+QMAKE_CC                = $${BR_CCACHE} $${CROSS_COMPILE}gcc
-+QMAKE_CXX               = $${BR_CCACHE} $${CROSS_COMPILE}g++
++QMAKE_CC                = $${CROSS_COMPILE}gcc
++QMAKE_CXX               = $${CROSS_COMPILE}g++
 +
 +#modifications to gcc-base.conf
 +QMAKE_CFLAGS           += $${BR_COMPILER_CFLAGS}

49 lines not on this page · raw message

index e783b4d..570cd35 100644
@@ -189,7 +189,6 @@ define QT5BASE_CONFIGURE_CMDS
 		-nomake tests \
 		-device buildroot \
 		-device-option CROSS_COMPILE="$(TARGET_CROSS)" \
-		-device-option BR_CCACHE="$(CCACHE)" \
 		-device-option BR_COMPILER_CFLAGS="$(TARGET_CFLAGS) $(QT5BASE_EXTRA_CFLAGS)" \
 		-device-option BR_COMPILER_CXXFLAGS="$(TARGET_CXXFLAGS) $(QT5BASE_EXTRA_CFLAGS)" \
 		$(QT5BASE_CONFIGURE_OPTS) \

index 6bc13d4..81dcfcc 100644
@@ -98,7 +98,6 @@ define $(2)_CONFIGURE_CMDS
 		-DBUILD_TESTS=OFF \
 		-DBUILD_TESTING=OFF \
 		-DBUILD_SHARED_LIBS=$$(if $$(BR2_STATIC_LIBS),OFF,ON) \
-		-DUSE_CCACHE=$$(if $$(BR2_CCACHE),ON,OFF) \
 		$$(CMAKE_QUIET) \
 		$$($$(PKG)_CONF_OPTS) \
 	)

@@ -245,8 +244,8 @@ $(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake:
 		-e 's#@@TARGET_CFLAGS@@#$(call qstrip,$(TARGET_CFLAGS))#' \
 		-e 's#@@TARGET_CXXFLAGS@@#$(call qstrip,$(TARGET_CXXFLAGS))#' \
 		-e 's#@@TARGET_LDFLAGS@@#$(call qstrip,$(TARGET_LDFLAGS))#' \
-		-e 's#@@TARGET_CC_NOCCACHE@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CC_NOCCACHE)))#' \
-		-e 's#@@TARGET_CXX_NOCCACHE@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CXX_NOCCACHE)))#' \
+		-e 's#@@TARGET_CC@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CC)))#' \
+		-e 's#@@TARGET_CXX@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CXX)))#' \
 		-e 's#@@CMAKE_SYSTEM_PROCESSOR@@#$(call qstrip,$(CMAKE_SYSTEM_PROCESSOR))#' \
 		$(TOPDIR)/support/misc/toolchainfile.cmake.in \
 		> $@

index cd41254..5cf381e 100644
@@ -27,33 +27,5 @@ set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 set(ENV{PKG_CONFIG_SYSROOT_DIR} "${RELOCATED_HOST_DIR}/@@STAGING_SUBDIR@@")
 
 # This toolchain file can be used both inside and outside Buildroot.
-# * When used inside Buildroot, ccache support is explicitly driven using the
-#   USE_CCACHE variable.
-# * When used outside Buildroot (i.e. when USE_CCACHE is not defined), ccache
-#   support is automatically enabled if the ccache program is available.
-if(DEFINED USE_CCACHE)
-	if(USE_CCACHE)
-		set(CMAKE_ASM_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/usr/bin/ccache")
-		set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/usr/bin/ccache")
-		set(CMAKE_C_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
-	else()
-		set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
-	endif()
-else()
-	find_program(CCACHE ccache HINTS "${RELOCATED_HOST_DIR}/usr/bin")
-	if(CCACHE)
-		set(CMAKE_ASM_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_C_COMPILER "${CCACHE}")
-		set(CMAKE_CXX_COMPILER "${CCACHE}")
-		set(CMAKE_C_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
-		message(STATUS "ccache program has been found and will be used for the build.")
-		message(STATUS "  To disable ccache, add -DUSE_CCACHE=OFF on the cmake command line.")
-	else()
-		set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
-		set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
-	endif()
-endif()
+set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC@@")
+set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX@@")

deleted file mode 100644
index 16f4aba..0000000
@@ -1,52 +0,0 @@
-From f24be9ae9ab01c7507a366e9d5529c444f0b7edd Mon Sep 17 00:00:00 2001
-From: Luca Ceresoli <[email protected]>
-Date: Fri, 10 Jul 2015 10:13:47 +0200
-Subject: [PATCH] proton-c: fix C compiler detection with _ARG1/_ARG2
-
-The C compiler commandline in CMake is composed by the concatenation of
-CMAKE_C_COMPILER + CMAKE_C_COMPILER_ARG1 + CMAKE_C_COMPILER_ARG2.
-
-In most use cases the two additional argument variables are empty, thus
-CMAKE_C_COMPILER can be used without any noticeable difference.
-
-The Buildroot embedded Linux build system [0], however, optionally exploits the
-CMAKE_C_COMPILER_ARG1 variable to speed up the cross-compilation of CMake-based
-packages using ccache. It does so by setting [1]:
-
-  CMAKE_C_COMPILER      = /path/to/ccache
-  CMAKE_C_COMPILER_ARG1 = /path/to/cross-gcc
-
-This works fine with other CMake-based packages, but proton-c's CMakeLists.txt
-calls gcc to extract the compiler version. It does so by calling
-"${CMAKE_C_COMPILER} -dumpversion", without honoring the two extra arguments.
-Within Buildroot with ccache enabled, this means calling
-"/path/to/ccache -dumpversion", which fails with the error:
-
-  ccache: invalid option -- 'd'
-
-Fix the compiler check by adding the two arguments.
-
-[0] http://buildroot.net/
-[1] http://git.buildroot.net/buildroot/tree/support/misc/toolchainfile.cmake.in?id=2015.05
-
-Signed-off-by: Luca Ceresoli <[email protected]>
----
- proton-c/CMakeLists.txt | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/proton-c/CMakeLists.txt b/proton-c/CMakeLists.txt
-index 93449a9..8c31a89 100644
---- a/proton-c/CMakeLists.txt
-+++ b/proton-c/CMakeLists.txt
-@@ -218,7 +218,7 @@ if (CMAKE_COMPILER_IS_GNUCC)
-     set (COMPILE_LANGUAGE_FLAGS "-std=c99")
-     set (COMPILE_PLATFORM_FLAGS "-std=gnu99")
- 
--    execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION
-+    execute_process(COMMAND ${CMAKE_C_COMPILER} ${CMAKE_C_COMPILER_ARG1} ${CMAKE_C_COMPILER_ARG2} -dumpversion OUTPUT_VARIABLE GCC_VERSION
-       OUTPUT_STRIP_TRAILING_WHITESPACE)
-     if (${GCC_VERSION} VERSION_LESS "4.3.0")
-       # Only a concern if contibuting code back.
--- 
-1.9.1
-

index 4b1ce7f..7dc0eac 100644
@@ -186,9 +186,6 @@ TARGET_READELF  = $(TARGET_CROSS)readelf
 TARGET_OBJCOPY  = $(TARGET_CROSS)objcopy
 TARGET_OBJDUMP  = $(TARGET_CROSS)objdump
 
-TARGET_CC_NOCCACHE  := $(TARGET_CC)
-TARGET_CXX_NOCCACHE := $(TARGET_CXX)
-
 ifeq ($(BR2_STRIP_strip),y)
 STRIP_STRIP_DEBUG := --strip-debug
 STRIP_STRIP_UNNEEDED := --strip-unneeded

index fdbca02..e8e2f02 100644
@@ -375,6 +375,8 @@ BR_CACHE_DIR = $(call qstrip,$(BR2_CCACHE_DIR))
 export BR_CACHE_DIR
 HOSTCC := $(CCACHE) $(HOSTCC)
 HOSTCXX := $(CCACHE) $(HOSTCXX)
+else
+export BR_NO_CCACHE
 endif
 
 # Scripts in support/ or post-build scripts may need to reference

index 3bd2803..52cf309 100644
@@ -26,15 +26,10 @@ HOST_CCACHE_CONF_OPTS += --with-bundled-zlib
 #    is already used by autotargets for the ccache package.
 #    BR_CACHE_DIR is exported by Makefile based on config option
 #    BR2_CCACHE_DIR.
-#  - ccache shouldn't use the compiler binary mtime to detect a change in
-#    the compiler, because in the context of Buildroot, that completely
-#    defeats the purpose of ccache. Of course, that leaves the user
-#    responsible for purging its cache when the compiler changes.
 #  - Change hard-coded last-ditch default to match path in .config, to avoid
 #    the need to specify BR_CACHE_DIR when invoking ccache directly.
 define HOST_CCACHE_PATCH_CONFIGURATION
 	sed -i 's,getenv("CCACHE_DIR"),getenv("BR_CACHE_DIR"),' $(@D)/ccache.c
-	sed -i 's,conf->compiler_check = x_strdup("mtime"),conf->compiler_check = x_strdup("none"),' $(@D)/conf.c
 	sed -i 's,"%s/.ccache","$(BR_CACHE_DIR)",' $(@D)/conf.c
 endef
 

index b9da398..103cbe1 100644
@@ -23,9 +23,10 @@ GCC_SOURCE ?= gcc-$(GCC_VERSION).tar.bz2
 # Xtensa special hook
 #
 
+HOST_GCC_XTENSA_OVERLAY_TAR = $(BR2_XTENSA_OVERLAY_DIR)/xtensa_$(call qstrip,$(BR2_XTENSA_CORE_NAME)).tar
+
 define HOST_GCC_XTENSA_OVERLAY_EXTRACT
-	tar xf $(BR2_XTENSA_OVERLAY_DIR)/xtensa_$(call qstrip,\
-		$(BR2_XTENSA_CORE_NAME)).tar -C $(@D) --strip-components=1 gcc
+	tar xf $(HOST_GCC_XTENSA_OVERLAY_TAR) -C $(@D) --strip-components=1 gcc
 endef
 
 #

@@ -237,6 +238,30 @@ endif
 
 HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CROSS_PATH_SUFFIX='".real"'
 
+ifeq ($(BR2_CCACHE),y)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += $(DL_DIR)/$(GCC_SOURCE)
+# Cfr. PATCH_BASE_DIRS in .stamp_patched, but we catch both versioned and
+# unversioned patches unconditionally
+HOST_GCC_COMMON_CCACHE_HASH_FILES += \
+	$(wildcard \
+		package/gcc/$(GCC_VERSION)/*.patch \
+		$(addsuffix $((PKG)_RAWNAME)/$(GCC_VERSION)/*.patch,$(call qstrip,$(BR2_GLOBAL_PATCH_DIR))) \
+		$(addsuffix $((PKG)_RAWNAME)/*.patch,$(call qstrip,$(BR2_GLOBAL_PATCH_DIR))))
+ifeq ($(BR2_xtensa),y)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += $(HOST_GCC_XTENSA_OVERLAY_TAR)
+endif
+ifeq ($(ARCH),powerpc)
+ifneq ($(BR2_SOFT_FLOAT),)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += package/gcc/$(GCC_VERSION)/1000-powerpc-link-with-math-lib.patch.conditional
+endif
+endif
+
+HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_HASH=\"`\
+	printf '%s' $($(PKG)_CONF_OPTS) $(GCC_VERSION) \
+		| sha256sum - $(HOST_GCC_COMMON_CCACHE_HASH_FILES) \
+		| cut -c -64 | tr -d '\n'`\"
+endif # BR2_CCACHE
+
 # The LTO support in gcc creates wrappers for ar, ranlib and nm which load
 # the lto plugin. These wrappers are called *-gcc-ar, *-gcc-ranlib, and
 # *-gcc-nm and should be used instead of the real programs when -flto is

index 3bd2803..52cf309 100644
@@ -26,15 +26,10 @@ HOST_CCACHE_CONF_OPTS += --with-bundled-zlib
 #    is already used by autotargets for the ccache package.
 #    BR_CACHE_DIR is exported by Makefile based on config option
 #    BR2_CCACHE_DIR.
-#  - ccache shouldn't use the compiler binary mtime to detect a change in
-#    the compiler, because in the context of Buildroot, that completely
-#    defeats the purpose of ccache. Of course, that leaves the user
-#    responsible for purging its cache when the compiler changes.
 #  - Change hard-coded last-ditch default to match path in .config, to avoid
 #    the need to specify BR_CACHE_DIR when invoking ccache directly.
 define HOST_CCACHE_PATCH_CONFIGURATION
 	sed -i 's,getenv("CCACHE_DIR"),getenv("BR_CACHE_DIR"),' $(@D)/ccache.c
-	sed -i 's,conf->compiler_check = x_strdup("mtime"),conf->compiler_check = x_strdup("none"),' $(@D)/conf.c
 	sed -i 's,"%s/.ccache","$(BR_CACHE_DIR)",' $(@D)/conf.c
 endef
 

index b9da398..103cbe1 100644
@@ -23,9 +23,10 @@ GCC_SOURCE ?= gcc-$(GCC_VERSION).tar.bz2
 # Xtensa special hook
 #
 
+HOST_GCC_XTENSA_OVERLAY_TAR = $(BR2_XTENSA_OVERLAY_DIR)/xtensa_$(call qstrip,$(BR2_XTENSA_CORE_NAME)).tar
+
 define HOST_GCC_XTENSA_OVERLAY_EXTRACT
-	tar xf $(BR2_XTENSA_OVERLAY_DIR)/xtensa_$(call qstrip,\
-		$(BR2_XTENSA_CORE_NAME)).tar -C $(@D) --strip-components=1 gcc
+	tar xf $(HOST_GCC_XTENSA_OVERLAY_TAR) -C $(@D) --strip-components=1 gcc
 endef
 
 #

@@ -237,6 +238,30 @@ endif
 
 HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CROSS_PATH_SUFFIX='".real"'
 
+ifeq ($(BR2_CCACHE),y)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += $(DL_DIR)/$(GCC_SOURCE)
+# Cfr. PATCH_BASE_DIRS in .stamp_patched, but we catch both versioned and
+# unversioned patches unconditionally
+HOST_GCC_COMMON_CCACHE_HASH_FILES += \
+	$(wildcard \
+		package/gcc/$(GCC_VERSION)/*.patch \
+		$(addsuffix $((PKG)_RAWNAME)/$(GCC_VERSION)/*.patch,$(call qstrip,$(BR2_GLOBAL_PATCH_DIR))) \
+		$(addsuffix $((PKG)_RAWNAME)/*.patch,$(call qstrip,$(BR2_GLOBAL_PATCH_DIR))))
+ifeq ($(BR2_xtensa),y)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += $(HOST_GCC_XTENSA_OVERLAY_TAR)
+endif
+ifeq ($(ARCH),powerpc)
+ifneq ($(BR2_SOFT_FLOAT),)
+HOST_GCC_COMMON_CCACHE_HASH_FILES += package/gcc/$(GCC_VERSION)/1000-powerpc-link-with-math-lib.patch.conditional
+endif
+endif
+
+HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_HASH=\"`\
+	printf '%s' $($(PKG)_CONF_OPTS) $(GCC_VERSION) \
+		| sha256sum - $(HOST_GCC_COMMON_CCACHE_HASH_FILES) \
+		| cut -c -64 | tr -d '\n'`\"
+endif # BR2_CCACHE
+
 # The LTO support in gcc creates wrappers for ar, ranlib and nm which load
 # the lto plugin. These wrappers are called *-gcc-ar, *-gcc-ranlib, and
 # *-gcc-nm and should be used instead of the real programs when -flto is

index 74aeb46..d795361 100644
@@ -286,6 +286,33 @@ config BR2_CCACHE_INITIAL_SETUP
 
 	  These initial settings are applied after ccache has been compiled.
 
+config BR2_CCACHE_USE_BASEDIR
+	bool "Use relative paths"
+	default y
+	help
+	  Allow ccache to convert absolute paths within the output
+	  directory into relative paths.
+
+	  During the build, many -I include directives are given with
+	  an absolute path. These absolute paths end up in the hashes
+	  that are computed by ccache. Therefore, when you build from a
+	  different directory, the hash will be different and the
+	  cached object will not be used.
+
+	  To improve cache performance, set this option to y. This
+	  allows ccache to rewrite absolute paths within the output
+	  directory into relative paths. Note that only paths within
+	  the output directory will be rewritten; therefore, if you
+	  change BR2_HOST_DIR to point outside the output directory and
+	  subsequently move it to a different location, this will lead
+	  to cache misses.
+
+	  This option has as a result that the debug information in the
+	  object files also has only relative paths. Therefore, make
+	  sure you cd to the build directory before starting gdb. See
+	  the section "COMPILING IN DIFFERENT DIRECTORIES" in the
+	  ccache manual for more information.
+
 endif
 
 config BR2_DEPRECATED

index 992471d..f6746ad 100644
@@ -33,3 +33,23 @@ make CCACHE_OPTIONS="--max-size=5G" ccache-options
 # zero statistics counters
 make CCACHE_OPTIONS="--zero-stats" ccache-options
 -----------------
+
++ccache+ makes a hash of the source files and of the compiler options.
+If a compiler option is different, the cached object file will not be
+used. Many compiler options, however, contain an absolute path to the
+staging directory. Because of this, building in a different output
+directory would lead to many cache misses.
+
+To avoid this issue, buildroot has the +Use relative paths+ option
+(+BR2_CCACHE_USE_BASEDIR+). This will rewrite all absolute paths that
+point inside the output directory into relative paths. Thus, changing
+the output directory no longer leads to cache misses.
+
+A disadvantage of the relative paths is that they also end up to be
+relative paths in the object file. Therefore, for example, the debugger
+will no longer find the file, unless you cd to the output directory
+first.
+
+See https://ccache.samba.org/manual.html#_compiling_in_different_directories[the
+ccache manual's section on "Compiling in different directories"] for
+more details about this rewriting of absolute paths.

index 103cbe1..420c4e9 100644
@@ -256,8 +256,10 @@ HOST_GCC_COMMON_CCACHE_HASH_FILES += package/gcc/$(GCC_VERSION)/1000-powerpc-lin
 endif
 endif
 
+# _CONF_OPTS contains some references to the absolute path of $(HOST_DIR),
+# so substitute those away.
 HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_HASH=\"`\
-	printf '%s' $($(PKG)_CONF_OPTS) $(GCC_VERSION) \
+	printf '%s' $(subst $(HOST_DIR), at HOST_DIR@,$($(PKG)_CONF_OPTS)) \
 		| sha256sum - $(HOST_GCC_COMMON_CCACHE_HASH_FILES) \
 		| cut -c -64 | tr -d '\n'`\"
 endif # BR2_CCACHE

index 0fd2b86..40d29a2 100644
@@ -20,6 +20,10 @@ ifeq ($(BR2_CCACHE),y)
 TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE='"$(CCACHE)"'
 endif
 
+ifeq ($(BR2_CCACHE_USE_BASEDIR),y)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_BASEDIR='"$(BASE_DIR)"'
+endif
+
 # For simplicity, build directly into the install location
 define TOOLCHAIN_BUILD_WRAPPER
 	$(Q)mkdir -p $(HOST_DIR)/usr/bin

index 74aeb46..d795361 100644
@@ -286,6 +286,33 @@ config BR2_CCACHE_INITIAL_SETUP
 
 	  These initial settings are applied after ccache has been compiled.
 
+config BR2_CCACHE_USE_BASEDIR
+	bool "Use relative paths"
+	default y
+	help
+	  Allow ccache to convert absolute paths within the output
+	  directory into relative paths.
+
+	  During the build, many -I include directives are given with
+	  an absolute path. These absolute paths end up in the hashes
+	  that are computed by ccache. Therefore, when you build from a
+	  different directory, the hash will be different and the
+	  cached object will not be used.
+
+	  To improve cache performance, set this option to y. This
+	  allows ccache to rewrite absolute paths within the output
+	  directory into relative paths. Note that only paths within
+	  the output directory will be rewritten; therefore, if you
+	  change BR2_HOST_DIR to point outside the output directory and
+	  subsequently move it to a different location, this will lead
+	  to cache misses.
+
+	  This option has as a result that the debug information in the
+	  object files also has only relative paths. Therefore, make
+	  sure you cd to the build directory before starting gdb. See
+	  the section "COMPILING IN DIFFERENT DIRECTORIES" in the
+	  ccache manual for more information.
+
 endif
 
 config BR2_DEPRECATED

index 992471d..f6746ad 100644
@@ -33,3 +33,23 @@ make CCACHE_OPTIONS="--max-size=5G" ccache-options
 # zero statistics counters
 make CCACHE_OPTIONS="--zero-stats" ccache-options
 -----------------
+
++ccache+ makes a hash of the source files and of the compiler options.
+If a compiler option is different, the cached object file will not be
+used. Many compiler options, however, contain an absolute path to the
+staging directory. Because of this, building in a different output
+directory would lead to many cache misses.
+
+To avoid this issue, buildroot has the +Use relative paths+ option
+(+BR2_CCACHE_USE_BASEDIR+). This will rewrite all absolute paths that
+point inside the output directory into relative paths. Thus, changing
+the output directory no longer leads to cache misses.
+
+A disadvantage of the relative paths is that they also end up to be
+relative paths in the object file. Therefore, for example, the debugger
+will no longer find the file, unless you cd to the output directory
+first.
+
+See https://ccache.samba.org/manual.html#_compiling_in_different_directories[the
+ccache manual's section on "Compiling in different directories"] for
+more details about this rewriting of absolute paths.

index 103cbe1..420c4e9 100644
@@ -256,8 +256,10 @@ HOST_GCC_COMMON_CCACHE_HASH_FILES += package/gcc/$(GCC_VERSION)/1000-powerpc-lin
 endif
 endif
 
+# _CONF_OPTS contains some references to the absolute path of $(HOST_DIR),
+# so substitute those away.
 HOST_GCC_COMMON_TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_HASH=\"`\
-	printf '%s' $($(PKG)_CONF_OPTS) $(GCC_VERSION) \
+	printf '%s' $(subst $(HOST_DIR), at HOST_DIR@,$($(PKG)_CONF_OPTS)) \
 		| sha256sum - $(HOST_GCC_COMMON_CCACHE_HASH_FILES) \
 		| cut -c -64 | tr -d '\n'`\"
 endif # BR2_CCACHE

index 749afd7..c78363a 100644
@@ -20,6 +20,10 @@ ifeq ($(BR2_CCACHE),y)
 TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE
 endif
 
+ifeq ($(BR2_CCACHE_USE_BASEDIR),y)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_BASEDIR='"$(BASE_DIR)"'
+endif
+
 # For simplicity, build directly into the install location
 define TOOLCHAIN_BUILD_WRAPPER
 	$(Q)mkdir -p $(HOST_DIR)/usr/bin