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ArchitectureRules: Enable -ftree-vrp, but use -fno-delete-null-pointer-checks everywhere.

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Most of the problems with tree-vrp stemmed from its deletion of null-pointer
checks (see linked commit in the source.) Now, GCC has a flag to control that,
and with it enabled I can boot to the desktop even with tree-vrp enabled.
This commit is contained in:
Augustin Cavalier 2018-06-17 14:56:53 -04:00
parent b06628148f
commit 29a21a63cb
1 changed files with 15 additions and 22 deletions
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37
build/jam/ArchitectureRules
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@ -19,30 +19,28 @@ rule ArchitectureSetup architecture
}
# disable strict aliasing on anything newer than gcc 2 as it may lead to
# unexpected results. also disable the tree-vrp (value range propagation)
# optimization for now as with the current gcc4 version we are using this
# results in some broken code.
# unexpected results.
# TODO: remove the -fno-strict-aliasing option when all code has been
# analyzed/fixed with regard to aliasing.
# TODO: retest/remove the -fno-tree-vrp option as soon as we have updated
# our gcc4 compiler. See this discussion on some issues:
# http://www.freelists.org/post/haiku-development/hrev45320-Yet-another-nonobvious-effect-of-ftreevrp-optimization
if $(gccVersion[1]) >= 3 {
gccBaseFlags += -fno-strict-aliasing -fno-builtin-fork ;
if $(HAIKU_CC_IS_CLANG_$(architecture)) != 1 {
gccBaseFlags += -fno-tree-vrp ;
}
gccBaseFlags += -fno-strict-aliasing ;
}
if $(HAIKU_CC_IS_CLANG_$(architecture)) = 1 {
gccBaseFlags += -fno-builtin-vfork ;
# Without this flag, GCC deletes many null-pointer checks that are
# technically undefined behavior (e.g. passing NULL to strdup, among
# others), which breaks both the kernel and various applications. See:
# - https://www.freelists.org/post/haiku-development/hrev45320-Yet-another-nonobvious-effect-of-ftreevrp-optimization
# - https://dev.haiku-os.org/ticket/13285#comment:8 (& subsequent comments)
# - https://dev.haiku-os.org/ticket/10803#comment:4 (& subsequent comments)
# Note that the Linux also does the same:
# - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a3ca86aea507904148870946d599e07a340b39bf
if $(gccVersion[1]) >= 3 && $(HAIKU_CC_IS_CLANG_$(architecture)) != 1 {
gccBaseFlags += -fno-delete-null-pointer-checks ;
}
# disable array bounds warnings on gcc 4.6 or newer since they trigger
# too many false positives. Coverity does a better job of this kind of
# analysis anyways.
if $(gccVersion[1]) >= 4 {
gccBaseFlags += -Wno-array-bounds ;
# disable some builtins that are incompatible with our definitions
if $(gccVersion[1]) >= 3 {
gccBaseFlags += -fno-builtin-fork -fno-builtin-vfork ;
}
local cpu = $(HAIKU_CPU_$(architecture)) ;
@ -331,11 +329,6 @@ rule KernelArchitectureSetup architecture
HAIKU_BOOT_LINKFLAGS = ;
HAIKU_BOOT_LDFLAGS = -Bstatic ;
if $(gccVersion[1]) >= 6 {
HAIKU_KERNEL_C++FLAGS += -fno-delete-null-pointer-checks ;
HAIKU_KERNEL_CCFLAGS += -fno-delete-null-pointer-checks ;
}
HAIKU_KERNEL_PIC_CCFLAGS = -fno-pic ;
HAIKU_KERNEL_PIC_LINKFLAGS = ;
HAIKU_KERNEL_ADDON_LINKFLAGS = ;