This is to avoid all need to do text comparison of built-in function names
when consuming the AST. All built-in functions get enumerants.
Will want to turn on soon. See PureOperatorBuiltins. See issue #8.
Previously if a non-void function implictly returned, a dummy variable
was created as return value. Now instead it returns the result of the
OpUndef instruction. This better conveys the presence of undefined
behavior to SPIR-V consuming tools (and humans).
It also saves one ID per occurrence...
There will be subsequent commits to refine semantics, esp. version-specific semantics,
as well as I/O functionality and restrictions.
Note: I'm getting white-space differences in the preprocessor test results,
which I'm not checking in. I think they need to be tagged as binary or something.
This patch introduces a new extension, GL_GOOGLE_include_directive,
to enable support #include directives. It depends on the extension
GL_GOOGLE_cpp_style_line_directive.
When an include directive is recognized by the preprocessor, it
executes a callback on the filepath argument to obtain the file
contents. That way the compilation client can deal with the file
system, include paths, etc.
Currently only accepts quoted filepaths -- no angle brackets yet.
According to the GLSL spec, the second parameter to #line should be
an integer source string number and __FILE__ will be substituted
with the integer source string number currently processed. This
patch extends the syntax of #line and __FILE__. Now #line accepts
as the second parameter a filename string quoted by double quotation
marks. And if such a #line is set, __FILE__ will be substituted with
the currently set filename string. The implementation is done via
introducing a new extension GL_GOOGLE_cpp_style_line_directive using
the extension framework.
The purpose is to support cpp-style #line directives, which is
required by #include.
Fixes issue #25. (char 255 aliased to -1 and missing tests for end of input).
1) All layers of input scanning now share a single EndOfInput value.
This avoids translation of it across layers of encapsulation.
2) Some places looking for end of line were not stopping on EndOfInput.
3) Use of "char" for the input made char values > 127 be negative numbers.
This allowed for aliasing of 255 to -1, etc. This is fixed by using
unsigned char.
This is just for '\' that's not before a new line.
Note the specification says it has no use other than as line continuation,
but #error is a grey area. (There are no escape sequences.)
After construction, the Loop is effectively const.
This perturbs the IDs in SPIR-V tests because the body block
is created before generating any of the loop code, rather than
only when the body is first referenced.
The loop test is always emitted before the loop body.
For do-while loops, use a phi node to track whether we're
on the first loop iteration, and only check the loop test
on the second and subsequent iterations.
For do-while loops, the loop test branch no longer occurs
at the top of the loop, so it must get its own selection
merge instruction.
A block can't be the target of more than one merge instruction.
So when the loop test executes after the body (as in do-while in GLSL)
we need to introduce a dummy block to be the target of the selection
merge just before the loop test conditional branch.
The other arm of the branch exits the loop and hence is the
"break block" exception in the structured control flow rules.
The current line number for the #line directive should be passed
in as parameter to the line directive callback. Without it, we
don't know how many empty lines we should output.
The line argument passed into the lineCallback function is the
literal value of the first argument of the #line directive.
lastLine in DoPreprocessing() should be updated taking into
consideration the different definitions for #line between specs.
Add a test to reveal the bug.
