This number should never be raised. If the value is exceeded, then it is
considered a bug in the Zig project that building the compiler takes
more than 8G of memory.
Partial revert of 1293f080fd
Deprioritizes #31510
These functions can only be exported when external libc components are
available due to the errno location dependency. Note that even when zig
libc is complete, on Windows, errno location will always be external (in
ucrtbase.dll).
It has been observed in practice on powerpc64(le)-linux that zig.o (in various
stages and build modes) is large enough that the +/- 32MB branch range of
PowerPC is insufficient to reach from one end of the code section to the other.
With LLVM 21, this leads to silent miscompiles that then crash at runtime. With
LLVM 22, it will at least lead to branch range errors that fail the compilation,
but that gets us no closer to a working compiler.
By using these options, we give the linker much greater flexibility to move code
and data around to satisfy these range constraints; without them, the linker is
not allowed to split up the huge code and data sections of zig.o to do so.
Similar issues have also been observed on powerpc-linux (32-bit), hexagon-linux,
and some variations of mips(64)(el)-linux. But let's be conservative for now;
those other targets can be added to the condition later.
As a data point to support this change, it's worth noting that LLD started
enabling these options for LTO precisely because the resulting large compilation
units ran into these range issues. In some abstract sense, Zig can be seen as
doing a limited form of "LTO" in the frontend, so it's not surprising that we
would hit the same issues.
error: memory usage peaked at 6.05GB (6047436800 bytes), exceeding the
declared upper bound of 6.04GB (6044158771 bytes)
This value isn't meant to be OS-specific anyway.
this gets the build runner compiling again on linux
this work is incomplete; it only moves code around so that environment
variables can be wrangled properly. a future commit will need to audit
the cancelation and error handling of this moved logic.
This avoids pessimizing concurrency on all machines due to e.g. the macOS
machine having high memory usage across the board due to 16K page size.
This also adds max_rss to test-unit and test-c-abi since those tend to eat a
decent chunk of memory too.
Andrew Kelley