105 lines
4.5 KiB
Diff
105 lines
4.5 KiB
Diff
From 07a446e7f869f79104bcc1d6accdc462e7bf7ba5 Mon Sep 17 00:00:00 2001
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From: Laszlo Ersek <lersek@redhat.com>
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Date: Fri, 2 Mar 2018 19:09:23 +0100
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Subject: [PATCH 2/3] BaseTools/header.makefile: add "-Wno-restrict"
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gcc-8 (which is part of Fedora 28) enables the new warning
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"-Wrestrict" in "-Wall". This warning is documented in detail
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at <https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html>; the
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introduction says
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> Warn when an object referenced by a restrict-qualified parameter (or, in
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> C++, a __restrict-qualified parameter) is aliased by another argument,
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> or when copies between such objects overlap.
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It breaks the BaseTools build (in the Brotli compression library) with:
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> In function 'ProcessCommandsInternal',
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> inlined from 'ProcessCommands' at dec/decode.c:1828:10:
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> dec/decode.c:1781:9: error: 'memcpy' accessing between 17 and 2147483631
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> bytes at offsets 16 and 16 overlaps between 17 and 2147483631 bytes at
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> offset 16 [-Werror=restrict]
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> memcpy(copy_dst + 16, copy_src + 16, (size_t)(i - 16));
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> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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> In function 'ProcessCommandsInternal',
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> inlined from 'SafeProcessCommands' at dec/decode.c:1833:10:
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> dec/decode.c:1781:9: error: 'memcpy' accessing between 17 and 2147483631
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> bytes at offsets 16 and 16 overlaps between 17 and 2147483631 bytes at
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> offset 16 [-Werror=restrict]
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> memcpy(copy_dst + 16, copy_src + 16, (size_t)(i - 16));
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> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Paolo Bonzini <pbonzini@redhat.com> analyzed the Brotli source in detail,
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and concluded that the warning is a false positive:
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> This seems safe to me, because it's preceded by:
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>
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> uint8_t* copy_dst = &s->ringbuffer[pos];
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> uint8_t* copy_src = &s->ringbuffer[src_start];
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> int dst_end = pos + i;
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> int src_end = src_start + i;
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> if (src_end > pos && dst_end > src_start) {
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> /* Regions intersect. */
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> goto CommandPostWrapCopy;
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> }
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>
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> If [src_start, src_start + i) and [pos, pos + i) don't intersect, then
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> neither do [src_start + 16, src_start + i) and [pos + 16, pos + i).
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>
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> The if seems okay:
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>
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> (src_start + i > pos && pos + i > src_start)
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>
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> which can be rewritten to:
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>
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> (pos < src_start + i && src_start < pos + i)
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>
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> Then the numbers are in one of these two orders:
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>
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> pos <= src_start < pos + i <= src_start + i
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> src_start <= pos < src_start + i <= pos + i
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>
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> These two would be allowed by the "if", but they can only happen if pos
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> == src_start so they degenerate to the same two orders above:
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>
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> pos <= src_start < src_start + i <= pos + i
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> src_start <= pos < pos + i <= src_start + i
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>
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> So it is a false positive in GCC.
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Disable the warning for now.
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Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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Cc: Cole Robinson <crobinso@redhat.com>
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Cc: Liming Gao <liming.gao@intel.com>
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Cc: Paolo Bonzini <pbonzini@redhat.com>
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Cc: Yonghong Zhu <yonghong.zhu@intel.com>
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Reported-by: Cole Robinson <crobinso@redhat.com>
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Contributed-under: TianoCore Contribution Agreement 1.1
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Signed-off-by: Laszlo Ersek <lersek@redhat.com>
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Message-Id: <20180302180924.4312-3-lersek@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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---
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BaseTools/Source/C/Makefiles/header.makefile | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/BaseTools/Source/C/Makefiles/header.makefile b/BaseTools/Source/C/Makefiles/header.makefile
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index 6c3826aecb..3feae10095 100644
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--- a/BaseTools/Source/C/Makefiles/header.makefile
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+++ b/BaseTools/Source/C/Makefiles/header.makefile
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@@ -47,9 +47,9 @@ INCLUDE = $(TOOL_INCLUDE) -I $(MAKEROOT) -I $(MAKEROOT)/Include/Common -I $(MAKE
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BUILD_CPPFLAGS = $(INCLUDE) -O2
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ifeq ($(DARWIN),Darwin)
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# assume clang or clang compatible flags on OS X
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-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-self-assign -Wno-unused-result -nostdlib -c -g
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+BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-restrict -Wno-self-assign -Wno-unused-result -nostdlib -c -g
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else
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-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-unused-result -nostdlib -c -g
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+BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-restrict -Wno-unused-result -nostdlib -c -g
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endif
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BUILD_LFLAGS =
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BUILD_CXXFLAGS = -Wno-unused-result
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--
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2.14.3
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