CVS commit: src/usr.bin/make

["Roland Illig" <rillig%netbsd.org@localhost>]

Module Name:    src
Committed By:   rillig
Date:           Sun Apr 11 12:46:55 UTC 2021

Modified Files:
        src/usr.bin/make: hash.c hash.h var.c

Log Message:
make: avoid allocating memory for simple variable names

The main change is in ParseVarname, where a Buffer is replaced with the
newly introduced LazyBuf.  LazyBuf is inspired by
https://golang.org/src/path/path.go.

In CanonicalVarname, the pre-comparison of the first letter of the
variable name is no longer necessary.  GCC 9 optimizes a fixed-length
memcmp so well that the code can finally be written to target human
readers, leaving the optimization to the compiler.


To generate a diff of this commit:
cvs rdiff -u -r1.63 -r1.64 src/usr.bin/make/hash.c
cvs rdiff -u -r1.39 -r1.40 src/usr.bin/make/hash.h
cvs rdiff -u -r1.915 -r1.916 src/usr.bin/make/var.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.