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| From: | Christian Jullien |
| Subject: | Re: [Tinycc-devel] Segfault on arm64 when making a function call with many arguments |
| Date: | Mon, 21 Jun 2021 19:35:53 +0200 |
Your second patch does not solve the issue on Risc-V. I continue to get coredump C. From: Tinycc-devel [mailto:tinycc-devel-bounces+eligis=orange.fr@nongnu.org] On Behalf Of Pursuer via Tinycc-devel Thank you. (I just used another email account and forgot to add nickname in previous email.) After inspecting the code more deeply, I found another way to fix this bug. Most functions in tccgen.c ,which modify the vstack , call vcheck_cmp() at the beginning (like "vsetc" ,"vswap", "vrotb" etc.). but "vpushv" seem to omit it. So the below patch should also work. diff --git a/tccgen.c b/tccgen.c index c36032a..dc6dd9d 100644 --- a/tccgen.c +++ b/tccgen.c @@ -1473,6 +1473,7 @@ ST_FUNC void vpushv(SValue *v) { if (vtop >= vstack + (VSTACK_SIZE - 1)) tcc_error("memory full (vstack)"); + vcheck_cmp(); vtop++; *vtop = *v; } I prefer latter patch, add vcheck_cmp() just like other vstack-related functions did. ------------------ Original ------------------ From: "jullien" <eligis@orange.fr>; Date: Sat, Jun 19, 2021 10:56 PM To: "jullien"<jullien@eligis.com>;"tinycc-devel"<tinycc-devel@nongnu.org>; Subject: Re: [Tinycc-devel] Segfault on arm64 when making a function call with many arguments All parameters go to the right arguments. So patch looks good #include <stdio.h> void map_add(int x0, int x1, int x2, int x3, int x4, int x5, int x6, int x7, in\ t x8) { printf("%d ", x0); printf("%d ", x1); printf("%d ", x2); printf("%d ", x3); printf("%d ", x4); printf("%d ", x5); printf("%d ", x6); printf("%d ", x7); printf("%d ", x8); } void main() { int A = 1; int B = 2; map_add(10, 20, 30, 40, 50, 60, 70, 80, A && B); } $ tcc foo.c -o foo && ./foo;echo 10 20 30 40 50 60 70 80 1 From: Tinycc-devel [mailto:tinycc-devel-bounces+eligis=orange.fr@nongnu.org] On Behalf Of Christian Jullien Hi just quickly tested on my RPi arm64. I don’t know if it works, i.e. all arguments go to the right parameter with the right value but, at least it no longer segfault. I’ll make more tests today. C. From: Tinycc-devel [mailto:tinycc-devel-bounces+eligis=orange.fr@nongnu.org] On Behalf Of pursuer2 via Tinycc-devel This bug may caused by "vpushv" SValue with VT_CMP flag. There should be only one VT_CMP SValue on vstack. I make below patch to fix it, then the compilation exit normally. But I have no arm64 device with GNU/Linux to verify the test. diff --git a/arm64-gen.c b/arm64-gen.c index 6389409..a9cbfa2 100644 --- a/arm64-gen.c +++ b/arm64-gen.c @@ -1017,6 +1017,9 @@ ST_FUNC void gfunc_call(int nb_args) if (stack >> 12) o(0xd14003ff | (stack >> 12) << 10); + if((vtop->r&VT_VALMASK)==VT_CMP){ + gv(RC_INT); + } // First pass: set all values on stack for (i = nb_args; i; i--) { vpushv(vtop - nb_args + i); ------------------ Original ------------------ From: "jullien" <eligis@orange.fr>; Date: Fri, Jun 18, 2021 04:04 PM To: "tinycc-devel"<tinycc-devel@nongnu.org>; Subject: Re: [Tinycc-devel] Segfault on arm64 when making a function call with many arguments I confirm it fails on arm64 (but works on arm 32bits). It also fails with complete prototype: void map_add(int a, int b, int c, int d, int e, int f, int g, int h, int i) {} C. From: Tinycc-devel [mailto:tinycc-devel-bounces+eligis=orange.fr@nongnu.org] On Behalf Of Arthur Williams Was trying to compile vim with tcc on arm64 but got a segfault. I can simplify it to the following case: } The bad pointer was generated in arm64-gen.c::gsym_addr and the actual segfault occurred in tcc.h::read16le. Removing one of the 0s or removing A/B or replacing A && B with a constant avoids the problem. Cannot repro on x86. I'm running musl on Linux and using the latest tcc from mob. |
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