From d9acf70759a258bf674cef91ae9289e9c7ce2428 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Tue, 29 Oct 2019 14:50:46 +0000 Subject: [PATCH] binutils: Be more forgiving of targets with large numbers of registers Currently if a target has a large ( > 1024 ) number of registers then we get a warning when dumping the DWARF whenever a register over the 1024 limit is referenced, this occurs in dwarf.c:frame_need_space. This check was initially introduced to guard against corrupted DWARF referencing stupidly large numbers of registers. The frame_need_space function already has a check in place so that, if a target specifies a set of known DWARF register names then we must only reference a register within this set, it is only after this check that we check for the 1024 limit. What this means is that if a target DOES NOT define a set of known register names and if we reference more than 1024 registers frame_need_space will give a warning. If a target DOES define a set of known registers and there are more than 1024 defined registers, and we try to reference a register beyond 1024 we will again get an error. This second case feels wrong to me. My thinking is that if a target defines a set of registers then it is not unreasonable to assume the tools can cope with that number of registers. And so, if the target defines 2000 named DWARF registers, frame_need_space should allow access to all of these registers. If a target does not define a set of named registers then the 1024 limit should remain. This is pretty arbitrary, but we do need to have some limit in place I think, so for now that seems as good as any. This is an entirely theoretical fix - there are no targets that define such large numbers of registers, but while experimenting with adding support for RISC-V CSRs I ran into this issue and felt like it was a good improvement. binutils/ChangeLog: * dwarf.c (frame_need_space): Compare dwarf_regnames_count against 0, and only warn about large numbers of registers if the number is more than the dwarf_regnames_count. Change-Id: Ifac1a999ff0677676e81ee373c4c044b6a700827 --- binutils/ChangeLog | 6 ++++++ binutils/dwarf.c | 4 ++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/binutils/ChangeLog b/binutils/ChangeLog index 7c0d0feadca..f833c14c125 100644 --- a/binutils/ChangeLog +++ b/binutils/ChangeLog @@ -1,3 +1,9 @@ +2019-11-22 Andrew Burgess + + * dwarf.c (frame_need_space): Compare dwarf_regnames_count against + 0, and only warn about large numbers of registers if the number is + more than the dwarf_regnames_count. + 2019-11-25 Christian Eggers * objdump.c (disassemble_data): Provide section parameter to diff --git a/binutils/dwarf.c b/binutils/dwarf.c index 2fe469f0603..62f2817d183 100644 --- a/binutils/dwarf.c +++ b/binutils/dwarf.c @@ -7378,7 +7378,7 @@ frame_need_space (Frame_Chunk *fc, unsigned int reg) if (reg < (unsigned int) fc->ncols) return 0; - if (dwarf_regnames_count + if (dwarf_regnames_count > 0 && reg > dwarf_regnames_count) return -1; @@ -7389,7 +7389,7 @@ frame_need_space (Frame_Chunk *fc, unsigned int reg) return -1; /* PR 17512: file: 2844a11d. */ - if (fc->ncols > 1024) + if (fc->ncols > 1024 && dwarf_regnames_count == 0) { error (_("Unfeasibly large register number: %u\n"), reg); fc->ncols = 0; -- 2.39.2