tinygo

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Tree: a2f95d6b87

Commit Graph

Author	SHA1	Message	Date
Ayke van Laethem	c1d697f868	compiler: fix indices into strings and arrays This PR fixes two bugs at once: 1. Indices were incorrectly extended to a bigger type. Specifically, unsigned integers were sign extended and signed integers were zero extended. This commit swaps them around. 2. The getelementptr instruction was given the raw index, even if it was a uint8 for example. However, getelementptr assumes the indices are signed, and therefore an index of uint8(200) was interpreted as an index of int8(-56).	3 years ago
Ayke van Laethem	0b7957d612	compiler: optimize string literals and globals This commit optimizes string literals and globals by setting the appropriate alignment and using a nil pointer in zero-length strings. - Setting the alignment for string values has a surprisingly large effect, up to around 2% in binary size. I suspect that LLVM will pick some default alignment for larger byte arrays if no alignment has been specified and forcing an alignment of 1 will pack all strings closer together. - Using nil for zero-length strings also has a positive effect, but I'm not sure why. Perhaps it makes some optimizations more trivial. - Always setting the alignment on globals improves code size slightly, probably for the same reasons setting the alignment of string literals improves code size. The effect is much smaller, however. This commit might have an effect on performance, but if it does this should be tested separately and such a large win in binary size should definitely not be ignored for small embedded systems.	4 years ago
Ayke van Laethem	24676d4366	compiler: add tests for strings This tests a few common operations on strings.	4 years ago

Author

SHA1

Message

Date

Ayke van Laethem

c1d697f868

compiler: fix indices into strings and arrays

This PR fixes two bugs at once:

 1. Indices were incorrectly extended to a bigger type. Specifically,
    unsigned integers were sign extended and signed integers were zero
    extended. This commit swaps them around.
 2. The getelementptr instruction was given the raw index, even if it
    was a uint8 for example. However, getelementptr assumes the indices
    are signed, and therefore an index of uint8(200) was interpreted as
    an index of int8(-56).

3 years ago

Ayke van Laethem

0b7957d612

compiler: optimize string literals and globals

This commit optimizes string literals and globals by setting the
appropriate alignment and using a nil pointer in zero-length strings.

  - Setting the alignment for string values has a surprisingly large
    effect, up to around 2% in binary size. I suspect that LLVM will
    pick some default alignment for larger byte arrays if no alignment
    has been specified and forcing an alignment of 1 will pack all
    strings closer together.
  - Using nil for zero-length strings also has a positive effect, but
    I'm not sure why. Perhaps it makes some optimizations more trivial.
  - Always setting the alignment on globals improves code size slightly,
    probably for the same reasons setting the alignment of string
    literals improves code size. The effect is much smaller, however.

This commit might have an effect on performance, but if it does this
should be tested separately and such a large win in binary size should
definitely not be ignored for small embedded systems.

4 years ago

Ayke van Laethem

24676d4366

compiler: add tests for strings

This tests a few common operations on strings.

4 years ago

3 Commits (a2f95d6b87418cc4a75892a43a6a405674aab876)