To better ensure that bytecode `@update` implementations return a 0/1
value (see https://github.com/llvm/llvm-project/pull/181199), this
changes the Python -> formatter bytecode compiler to require that Python
`update` methods be declared to return `bool`.
A declaration like this will be a compiler error:
```py
def update(self):
# implementation...
```
The `num_temps` was introduced under the mistaken understanding of the
index values given to the `pick` op. I thought the `pick` index was from
the top of the stack, but it's from the bottom. The model of indexing
from the bottom of the stack has the benefit of simplifying the
compiler.
Replace "compile" with "assemble" in formatter_bytecode. This is in
preparation for the addition of a Python to formatter bytecode compiler.
It will be more clear to have one meaning for "compile".
Add the ability to generate a C source file, which is in addition to the
existing functionality of generating binary.
An example of the generated source:
```c
#ifdef __APPLE__
#define FORMATTER_SECTION "__DATA_CONST,__lldbformatters"
#else
#define FORMATTER_SECTION ".lldbformatters"
#endif
__attribute__((used, section(FORMATTER_SECTION)))
unsigned char _Account_synthetic[] =
// version
"\x01"
// remaining record size
"\x15"
// type name size
"\x07"
// type name
"Account"
// flags
"\x00"
// sig_get_num_children
"\x02"
// program size
"\x02"
// program
"\x20\x01"
// sig_get_child_at_index
"\x04"
// program size
"\x06"
// program
"\x02\x20\x00\x23\x11\x60"
;
```
Changes `formatter_bytecode.compile_file` to return a `BytecodeSection`
value. The `BytecodeSection` holds the data that needs to be emitted to
an `__lldbformatters` section.
The `BytecodeSection` currently provides `write_binary`, but will be
updated in a follow up commit to include `write_source` which will allow
the data to be emitted as C source code, or Swift source code. This will
make it easier to integrate into build systems, as it's easier to get
data into a binary via source code, than as a raw binary file.
Updates formatter_bytecode.py to support compilation and disassembly for
synthetic formatters, in other words support for multiple functions
(signatures).
This includes a number of other changes:
* String parsing and encoding have bugs fixed
* CLI args are updated, primarily to support an output file
* Added uleb encoding/decoding support
This work is a prelude the ongoing work of a Python to formatter
bytecode compiler. The python compiler to emit assembly, and this module
(formatter_bytecode) will compile it into binary bytecode.
`GetSyntheticValue` in synthetic providers which need to operate on raw
root values, but will often want to use the synthetic value of children,
or nested children.
This PR adds a proof-of-concept for a bytecode designed to ship and
run LLDB data formatters. More motivation and context can be found in
the formatter-bytecode.rst file and on discourse.
https://discourse.llvm.org/t/a-bytecode-for-lldb-data-formatters/82696
Relanding with a fix for a case-sensitive path.
This PR adds a proof-of-concept for a bytecode designed to ship and
run LLDB data formatters. More motivation and context can be found in
the formatter-bytecode.rst file and on discourse.
https://discourse.llvm.org/t/a-bytecode-for-lldb-data-formatters/82696
Relanding with a fix for a case-sensitive path.
