single frame and non-overlapping variables reuse frame slots.
As a result, entering and exiting blocks no longer requires
code execution, which means jumps across block boundaries
should be doable now. Frame slot initialization happens at
definition time now, instead of at frame creation time. As an
added bonus, Scope's are now exclusively compile-time objects
and we no longer need to specially track the function
activation frame for access to out vars.
R=rsc
APPROVED=rsc
DELTA=313 (102 added, 90 deleted, 121 changed)
OCL=32416
CL=32420
function calling. Implement a type compiler and named types.
Implement a universal scope containing built-in named types,
and some built-in constants. Implement a simple virtual
machine for executing statements and single-valued return.
Fix many places that incorrectly dealt with named types. In
particular, the Type.Zero methods now use the type's bit count
to determine the appropriate value representation. As a
result, a bit count of 0 now means architecture-dependent and
bounded types use unsafe.Sizeof to determine the correct
bounds. Previously, the bounds on a 32-bit machine would have
been wrong.
Eliminated Type.compatible, since the implementation is
equivalent for all types. Added Type.rep that shallowly
strips named types. Replaced almost all uses of Type.literal
with Type.rep.
Fix implementation of assign-op's so it only evaluates the
left side once. As part of this, there is now a generic way
to separate out the effect and value of an expression.
R=rsc
APPROVED=rsc
DELTA=1530 (1244 added, 68 deleted, 218 changed)
OCL=32184
CL=32230
all type-specific value functions, and use ZeroVal to create
new frames. Remove Value.Type; it was unused and difficult
for values with composite types. Add Value.Assign methods.
R=rsc
APPROVED=rsc
DELTA=282 (135 added, 90 deleted, 57 changed)
OCL=31894
CL=31930
container for values.
Instead of having one evaluator function that returns a
generic Value, there is now an evaluator function for each
generalized type that simply returns a native type.
The compiler is more type-safe now because there are almost no
type conversions at evaluation time and it's impossible to
invoke a nil evaluator function during evaluation. This also
makes ideals and pointers really clean.
As an added bonus, expression evaluation should be faster
because it doesn't require heap allocation for every
intermediate value, type switches, or lots of conversions to
and from Value. It also involves fewer function calls.
R=rsc
APPROVED=rsc
DELTA=431 (280 added, 115 deleted, 36 changed)
OCL=31705
CL=31709
pointer types, supports literals, identifiers, type-checking
most unary and binary operators, "compiling" a few unary and
binary operators, and assignment and declaration statements.
R=rsc
APPROVED=rsc
DELTA=1751 (1751 added, 0 deleted, 0 changed)
OCL=31309
CL=31691
