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This patch implements a new clang driver flag -fsafe-buffer-usage-suggestions which allows turning the smart suggestion machine on and off (defaults to off). This is valuable for stability reasons, as the machine is being rapidly improved\ and we don't want accidental breakages to ruin the build for innocent users. It is also arguably useful in general because it enables separation of concerns between project contributors: some users will actively update the code to conform to the programming model, while others simply want to make sure that they aren't regressing it. Finally, there could be other valid reasons to opt out of suggestions entirely on some codebases (while continuing to enforce -Wunsafe-buffer-usage warnings), such as lack of access to hardened libc++ (or even to the C++ standard library in general) on the target platform. When the flag is disabled, the unsafe buffer usage analysis is reduced to an extremely minimal mode of operation that contains virtually no smarts: not only it doesn't offer automatic fixits, but also textual suggestions such as "change the type of this variable to std::span to preserve bounds information" are not displayed, and in fact the machine doesn't even try to blame specific variables in the first place, it simply warns on the operations and leaves everything else to the user. So this flag turns off a lot more of our complex machinery than what we already turn off in presence of say -fno-diagnostic-fixit-info. The flag is discoverable: when it's off, the warnings are accompanied by a note: telling the user that there's a flag they can use. Differential Revision: https://reviews.llvm.org/D146669
15 lines
362 B
C
15 lines
362 B
C
// RUN: %clang_cc1 -Wunsafe-buffer-usage -fsafe-buffer-usage-suggestions \
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// RUN: %s -verify %s
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void gnu_stmtexpr_crash(void) {
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struct A {};
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struct B {
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struct A a;
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};
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struct B b = {{
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// This is a statement-expression (GNU extension).
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({ int x; }) // no-crash // expected-warning{{excess elements in struct initializer}}
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}};
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}
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