llvm-project/clang/test/Preprocessor/print_empty_include.c

// RUN: %clang_cc1 -E -P %s | count 1
// Ensure no superfluous newlines are printed
// llvm.org/PR51616

#include "print_empty_include.h"
#include "print_empty_include.h"

#define EXPANDED_TO_NOTHING
EXPANDED_TO_NOTHING
[Preprocessor] Elide empty line(s) at start of file. In -P mode, PrintPPOutputPPCallbacks::MoveToLine started at least one newline if current and target line number mismatched. The method is also called when entering a new file, be it the main file or an include file. In this situation line numbers always almost mismatch, resulting in a newline for each occurance even if no tokens have been printed in-between. Empty lines at the beginning of the output must be trimmed because it may be parsed by scripts expecting the result to appear on the first output line, as done by LibreOffice's configure script. Fix by only emitting a newline if tokens have been printed so far using the EmittedTokensOnThisLine flag. Also adding a test case of FileChanged callbacks occuring with empty include files. This fixes llvm.org/PR51616 2021-08-26 00:31:53 +08:00			`// RUN: %clang_cc1 -E -P %s \| count 1`
			`// Ensure no superfluous newlines are printed`
			`// llvm.org/PR51616`

			`#include "print_empty_include.h"`
			`#include "print_empty_include.h"`

			`#define EXPANDED_TO_NOTHING`
			`EXPANDED_TO_NOTHING`