Preprocessor: 1) Rationalize the "fixed atom" scheme, 2) remove redundant lookups when the text is already available.

This simplification is a prelude to eliminating what I appear unnecessary
symbol inserts into tables when tokenizing in the preprecessor, which
show up as taking notable time. (Performance issue.)  It also simply makes
the preprocessor easier to understand, which it is badly in need of.

Front-end: Add error-recovery code for a switch statement that ends with a case/default that has no statements.

Added a setStringsWithLengths() method to TShader.

Removed the single usage of exceptions in all of glslang.

This allows us to pass through non null-terminated strings.

Comment out some dead assignments per suggestion from static analysis…

Code is left in as comments for clarity to humans.

Protect location setting methods from writing to non-existing strings.

TInputScanner advances its internal indices to the next character at
the end of get(), which means, after reading in the last character
in the user-provided shader string, internal index (currentSource)
will point to the next shader string (currentSource == numSources),
which doesn't exist. Then if a location setting method is called,
we will write to some out-of-bound memory.

A test case for this is "#line 10000\n". The eval() method in CPPline()
will evaluate 10000, but at the same time it reads in the next
token, '\n', and the currentSource will be numSources in TInputScanner.
Then a parseContext.setCurrentLine() is called, we are writing to
out-of-bound memory. Another test case will be "#line 10000 0\n".

Preprocessing directive handling

Also seems to pick up some white-space (line-ending) test differences with a
prevoius checkin.

Added error output to the preprocessor.

This patch distinguishes preprocessing errors with normal parsing
errors and gives glslangValidator the ability to output preprocessing
errors.

This patch distinguishes preprocessing errors with normal parsing
errors and gives glslangValidator the ability to output preprocessing
errors.

We output empty lines before processing non-whitespace tokens,
not after done processing them.

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.

Simplify function calls for extensionsTurnedOn().

Lots of places in the code use extensionsTurnedOn(1, ...). This
patch introduces a new method, extensionTurnedOn(), for testing
if a single extension is turned on.

Fix warnings compiling on x64 with size_t to int casts

Lots of places in the code use extensionsTurnedOn(1, ...). This
patch introduces a new method, extensionTurnedOn(), for testing
if a single extension is turned on.

Updated command-line options, adding -o for saving binaries, -G for OpenGL SPIR-V validation, -v etc.

Old uses should still work as they did before.
Also encapsulated use of these flags during parsing, for the parse context.
Added SPIR-V version to -v.

include by relative path, so root doesn't need to be in the search path

Fix for most Xcode/clang warnings on OSX

The infrastructure is in place to not do text comparisons for "texture" ... for deducing type of
texture call.  But, it is not yet turned on, as it could break some consumers.  Am soliciting
any feedback on that.

See in Initialize.cpp: const bool PureOperatorBuiltins = false;  // could break backward compatibility; pending feedback

- member initializing order in some constructors
- missing default branches in switch-case
- uninitialized variable if switch-case default (uncritical because
  program would exit)
- && and || brace warnings in if()

Front-end: move to rational internal array-of-array interfaces and design.  (A-of-A is not yet implemented though.)

glslang -> SPIR-V: smear scalars for integer (scalar * vector).  OpVectorTimesScalar is only for floats.