Commit Graph

6 Commits

Author SHA1 Message Date
Ayke van Laethem 13ca0c87ed
[lld][WebAssembly] Align __heap_base
__heap_base was not aligned. In practice, it will often be aligned
simply because it follows the stack, but when the stack is placed at the
beginning (with the --stack-first option), the __heap_base might be
unaligned. It could even be byte-aligned.

At least wasi-libc appears to expect that __heap_base is aligned:
659ff41456/dlmalloc/src/malloc.c (L5224)

While WebAssembly itself does not appear to require any alignment for
memory accesses, it is sometimes required when sharing a pointer
externally. For example, WASI might expect alignment up to 8:
https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md#-timestamp-u64

This issue got introduced with the addition of the --stack-first flag:
https://reviews.llvm.org/D46141
I suspect the lack of alignment wasn't intentional here.

Differential Revision: https://reviews.llvm.org/D106499
2021-07-24 14:03:26 +02:00
Sam Clegg fd1c894a4a [lld][WebAssembly] Convert some lld tests to assembly
When we originally wrote these tests we didn't have a stable and
fleshed out assembly format.  Now we do so we should prefer that
over llvm ir for lld tests to avoid including more part of llvm
than necessary in order to run the test.

This change converts just 30 out of about 130 test files. More to
come when I have some more time.

Differential Revision: https://reviews.llvm.org/D80361
2020-05-28 16:52:01 -07:00
Sam Clegg caa0db1318 [lld][WebAssembly] Add optional symbols after input file handling
This allows undefined references in input files be resolved by the
optional symbols.  Previously we were doing this before input file
reading which means it was working only for command line symbols
references (i.e. -u or --export).

Also use addOptionalDataSymbol for __dso_handle and make all optional
symbols hidden by default.

Differential Revision: https://reviews.llvm.org/D65920

llvm-svn: 368310
2019-08-08 16:58:36 +00:00
Sam Clegg 7d4ec5af6c [WebAssembly] Don't export __data_end and __heap_base by default.
These can still be exported via --export if needed.

Differential Revision: https://reviews.llvm.org/D62744

llvm-svn: 362276
2019-05-31 22:51:59 +00:00
Sam Clegg 752494bfe3 [WebAssembly] Check function signatures by default
But only produce a warning (for now) unless --fatal-warnings
is passed.

Differential Revision: https://reviews.llvm.org/D46484

llvm-svn: 331574
2018-05-05 01:23:07 +00:00
Sam Clegg a0f095ebd7 [WebAssembly] Add --stack-first option which places the shadow stack at start of linear memory
Fixes https://bugs.llvm.org/show_bug.cgi?id=37181

Differential Revision: https://reviews.llvm.org/D46141

llvm-svn: 331467
2018-05-03 17:21:53 +00:00