Re: gcc behavior on memory exhaustion

["Richard Earnshaw (lists)" <Richard dot Earnshaw at arm dot com>]

On 09/08/17 14:05, Andrew Roberts wrote:
> I routinely build the weekly snapshots and RC's, on x64, arm and aarch64.
> 
> The last gcc 8 snapshot and the two recent 7.2 RC's have failed to build
> on aarch64 (Raspberry Pi 3, running Arch Linux ARM). I have finally
> traced this to the system running out of memory. I guess a recent kernel
> update had changed the memory page size and the swap file was no longer
> being used because the page sizes didn't match.
> 
> Obviously this is my issue, but the error's I was getting from gcc did
> not help. I was getting ICE's, thus:
> 
> /usr/local/gcc/bin/g++ -Wall -Wextra -Wno-ignored-qualifiers
> -Wno-sign-compare -Wno-write-strings -std=c++14 -pipe -march=armv8-a
> -mcpu=cortex-a53 -mtune=cortex-a53 -ftree-vectorize -O3
> -DUNAME_S=\"linux\" -DUNAME_M=\"aarch64\" -DOSMESA=1 -I../libs/include
> -DRASPBERRY_PI -I/usr/include/freetype2 -I/usr/include/harfbuzz
> -I/usr/include/unicode   -c -o glerr.o glerr.cpp
> {standard input}: Assembler messages:
> {standard input}: Warning: end of file not at end of a line; newline
> inserted
> {standard input}:204: Error: operand 1 must be an integer register -- `mov'
> {standard input}: Error: open CFI at the end of file; missing
> .cfi_endproc directive
> g++: internal compiler error: Killed (program cc1plus)
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <https://gcc.gnu.org/bugs/> for instructions.
> make: *** [<builtin>: glerr.o] Error 4
> make: *** Waiting for unfinished jobs....
> 
> I was seeing the problem when building using make -j2. Both building gcc
> and building large user projects.
> 
> There are two issues here:
> 
> 1) There was discussion about increasing the amount of memory gcc would
> reserve to help speed up compilation of large source files, I wondered
> if this could be a factor.
> 
> 2) It would be nice to see some sort of out of memory error, rather than
> just an ICE.
> 
> The system has 858Mb of  RAM without the swap file.
> 
> Building a single source file seems to use up to 97% of the available
> memory (for a 2522 line C++ source file).
> 
> make -j2 is enough to cause the failure.
> 
> Regards
> 
> Andrew Roberts
> 
> 
> 
> 
> 
> 

If you think gcc is using an unreasonable amount of memory for a
particular bit of code then please file a bug report, with pre-processed
source code (don't assume that because the sources are part of gcc we
can reproduce your setup).  You should also set the keyword "memory-hog"
on the report.  If you have statistics for older versions of the
compiler, or for other targets that will add evidence for us to look at.

R.