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llvm-project/clang/test/CodeCompletion/pragma-macro-token-caching.c

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[Preprocessor] Fix incorrect token caching that occurs when lexing _Pragma in macro argument pre-expansion mode when skipping a function body This commit fixes a token caching problem that currently occurs when clang is skipping a function body (e.g. when looking for a code completion token) and at the same time caching the tokens for _Pragma when lexing it in macro argument pre-expansion mode. When _Pragma is being lexed in macro argument pre-expansion mode, it caches the tokens so that it can avoid interpreting the pragma immediately (as the macro argument may not be used in the macro body), and then either backtracks over or commits these tokens. The problem is that, when we're backtracking/committing in such a scenario, there's already a previous backtracking position stored in BacktrackPositions (as we're skipping the function body), and this leads to a situation where the cached tokens from the pragma (like '(' 'string_literal' and ')') will remain in the cached tokens array incorrectly even after they're consumed (in the case of backtracking) or just ignored (in the case when they're committed). Furthermore, what makes it even worse, is that because of a previous backtracking position, the logic that deals with when should we call ExitCachingLexMode in CachingLex no longer works for us in this situation, and more tokens in the macro argument get cached, to the point where the EOF token that corresponds to the macro argument EOF is cached. This problem leads to all sorts of issues in code completion mode, where incorrect errors get presented and code completion completely fails to produce completion results. rdar://28523863 Differential Revision: https://reviews.llvm.org/D28772 llvm-svn: 296140
2017-02-25 01:45:16 +08:00
#define Outer(action) action
void completeParam(int param) {
;
Outer(__extension__({ _Pragma("clang diagnostic push") }));
param;
}
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:7:1 %s | FileCheck %s
// CHECK: param : [#int#]param
void completeParamPragmaError(int param) {
Outer(__extension__({ _Pragma(2) })); // expected-error {{_Pragma takes a parenthesized string literal}}
Diagnose -Wunused-value based on CFG reachability (This relands 59337263ab45d7657e and makes sure comma operator diagnostics are suppressed in a SFINAE context.) While at it, add the diagnosis message "left operand of comma operator has no effect" (used by GCC) for comma operator. This also makes Clang diagnose in the constant evaluation context which aligns with GCC/MSVC behavior. (https://godbolt.org/z/7zxb8Tx96) Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D103938
2021-06-24 14:46:42 +08:00
param;
[Preprocessor] Fix incorrect token caching that occurs when lexing _Pragma in macro argument pre-expansion mode when skipping a function body This commit fixes a token caching problem that currently occurs when clang is skipping a function body (e.g. when looking for a code completion token) and at the same time caching the tokens for _Pragma when lexing it in macro argument pre-expansion mode. When _Pragma is being lexed in macro argument pre-expansion mode, it caches the tokens so that it can avoid interpreting the pragma immediately (as the macro argument may not be used in the macro body), and then either backtracks over or commits these tokens. The problem is that, when we're backtracking/committing in such a scenario, there's already a previous backtracking position stored in BacktrackPositions (as we're skipping the function body), and this leads to a situation where the cached tokens from the pragma (like '(' 'string_literal' and ')') will remain in the cached tokens array incorrectly even after they're consumed (in the case of backtracking) or just ignored (in the case when they're committed). Furthermore, what makes it even worse, is that because of a previous backtracking position, the logic that deals with when should we call ExitCachingLexMode in CachingLex no longer works for us in this situation, and more tokens in the macro argument get cached, to the point where the EOF token that corresponds to the macro argument EOF is cached. This problem leads to all sorts of issues in code completion mode, where incorrect errors get presented and code completion completely fails to produce completion results. rdar://28523863 Differential Revision: https://reviews.llvm.org/D28772 llvm-svn: 296140
2017-02-25 01:45:16 +08:00
}
// RUN: %clang_cc1 -fsyntax-only -verify -code-completion-at=%s:16:1 %s | FileCheck %s