Messages in this thread | | | From | Arnd Bergmann <> | Date | Wed, 20 Feb 2019 22:40:29 +0100 | Subject | Re: [PATCH] kasan: turn off asan-stack for clang-8 and earlier |
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On Wed, Feb 20, 2019 at 10:13 PM Arnd Bergmann <arnd@arndb.de> wrote: > > In the example in https://bugs.llvm.org/show_bug.cgi?id=38809#c12 > (https://godbolt.org/z/ylsGSQ) there is no inlining, yet clang uses > over ten times as much stack space as gcc, for reasons I still > can't explain. My assumption right now is that the underlying bug > causes most of the problems with excessive stack usage in > allmodconfig kernels.
Here is an even more minimal example:
struct s { int i[5]; } f(void); void g(void) { f(); f();}
https://godbolt.org/z/d_KWkh
It's clear that clang does /something/ here when asan-stack=1 is set, but I fail to see what it is, or why that is necessary.
The output of clang with asan-stack=0 is the expected code, and basically identical to what gcc produces with or without asan-stack.
Arnd
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