When testing amalgamating other projects it was found: invalid Unicode errors were tripping Python's text IO, and the header search order appears differs from the shell version.
Intel Control-flow Enforcement Technology (CET):
https://en.wikipedia.org/wiki/Control-flow_integrity#Intel_Control-flow_Enforcement_Technology
requires that on Linux, all linker input files are marked as CET enabled
in .note.gnu.property section. For high-level language source codes,
.note.gnu.property section is added by compiler with the -fcf-protection
option. For assembly sources, include <cet.h> to add .note.gnu.property
section.
When decompressing with `-q` and an output file, the progress bar was mistakenly printed. This is a minimal fix, with a larger refactor to be stacked on top of it.
Fixes#2967.
oss-fuzz uncovered a scenario where we're evaluating the cost of litLength = 131072,
which can't be represented in the zstd format, so we accessed 1 beyond LL_bits.
Fix the issue by making it cost 1 bit more than litLength = 131071.
There are still follow ups:
1. This happened because literals_cost[0] = 0, so the optimal parser chose 36 literals
over a match. Should we bound literals_cost[literal] > 0, unless the block truly only
has one literal value?
2. When no matches are found, the cost model isn't updated. In this case no matches were
found for an entire block. So the literals cost model wasn't updated at all. That made
the optimal parser think literals_cost[0] = 0, where it is actually quite high, since
the block was entirely random noise.
Credit to OSS-Fuzz.
xxHash symbols are present in `libzstd.so`, but they are local and therefore
unavailable outside the lib. There are two possible solutions to the problem.
We could make those symbols global, or we could remove the dependency.
This commit chooses the latter approach. I suppose this comes at the cost of
code size / build time. I'm open to comments on whether this is a good thing
to do, especially since this will apply even when we are statically linking
everything.
This commit makes several changes:
1. It adds modules for the dictionary builder and errors headers.
2. It captures all of the macros that are used to configure these headers.
When the headers are imported as modules and one of these macros is defined
the compiler issues a warning that it needs to be defined on the CLI.
3. It promotes the modulemap file into the root of the lib directory.
Experimentation shows that clang's `-fimplicit-module-maps` will find the
modulemap when placed here, but not when it's put in a subdirectory.
