readable writable attr _nmc: NitMethodContext
+ # C outputs written outside the current C function.
+ readable writable attr _out_contexts: Array[CContext] = new Array[CContext]
+
# Generate an fprintf to display an error location
meth printf_locate_error(node: PNode): String
do
- var s = "fprintf(stderr, \""
+ var s = new Buffer.from("fprintf(stderr, \"")
if nmc != null then s.append(" in %s")
s.append(" (%s:%d)\\n\", ")
if nmc != null then s.append("LOCATE_{nmc.method.cname}, ")
s.append("LOCATE_{module.name}, {node.line_number});")
- return s
+ return s.to_s
end
redef init(module: MMSrcModule)
# Association between nit variable and the corrsponding c variable
attr _varnames: Map[Variable, String] = new HashMap[Variable, String]
+ # Are we currenlty in a closure definition?
+ readable writable attr _in_closure: Bool = false
+
meth varname(v: Variable): String
do
- return _varnames[v]
+ if _in_closure then
+ return "closctx->{_varnames[v]}"
+ else
+ return _varnames[v]
+ end
end
# Return the next available variable
var v = variable(_variable_index)
_variable_index = _variable_index + 1
if _variable_index > _variable_index_max then
+ #visitor.add_decl("val_t {v};")
_variable_index_max = _variable_index
end
return v
return s
end
+ # Next available closure variable number
+ attr _closurevariable_index: Int = 0
+
+ meth register_closurevariable(v: ClosureVariable): String
+ do
+ var s = "closurevariable[{_closurevariable_index}]"
+ _closurevariable_index += 1
+ _varnames[v] = s
+ if _in_closure then
+ return "(closctx->{s})"
+ else
+ return s
+ end
+ end
+
# Return the ith variable
protected meth variable(i: Int): String
do
- return "variable[{i}]"
+ if _in_closure then
+ return "(closctx->variable[{i}])"
+ else
+ return "variable[{i}]"
+ end
end
# Mark the variable available
else
visitor.add_decl("val_t *variable = NULL;")
end
+ if _closurevariable_index > 0 then
+ visitor.add_decl("void *closurevariable[{_closurevariable_index}];")
+ else
+ visitor.add_decl("void **closurevariable = NULL;")
+ end
end
init(v: CompilerVisitor) do _visitor = v
# Current method compiled
readable attr _method: MMSrcMethod
- # Is a "return" found in the method body
- readable writable attr _has_return: Bool = false
-
# Association between parameters and the corresponding variables
readable writable attr _method_params: Array[ParamVariable]
# Variable where a functionnal nit return must store its value
readable writable attr _return_value: String
+ # Variable where a functionnal nit break must store its value
+ readable writable attr _break_value: String
+
+ # Variable where a functionnal nit continue must store its value
+ readable writable attr _continue_value: String
+
init(method: MMSrcMethod)
do
_method = method
###############################################################################
+redef class ClosureVariable
+ readable writable attr _ctypename: String
+end
+
redef class MMMethod
# Compile a call on self for given arguments
# Most calls are compiled with a table access,
cargs.add("init_table /*YYY*/")
end
- var m = "(({cname}_t)CALL({cargs[0]},{global.color_id}))"
+ var m = "{global.meth_call}({cargs[0]})"
var vcall = "{m}({cargs.join(", ")}) /*{local_class}::{name}*/"
if name == ee then
vcall = "UNTAG_Bool({vcall})"
# Compile a call as call-next-method on self with given args
meth compile_super_call(v: CompilerVisitor, cargs: Array[String]): String
do
- var m = "(({cname}_t)CALL({cargs[0]},{color_id_for_super}))"
+ var m = "{super_meth_call}({cargs[0]})"
var vcall = "{m}({cargs.join(", ")}) /*super {local_class}::{name}*/"
return vcall
end
+
+ # Cname of the i-th closure C struct type
+ protected meth closure_cname(i: Int): String
+ do
+ return "WBT_{cname}_{i}"
+ end
end
redef class MMAttribute
end
redef class MMSrcMethod
+
# Compile and declare the signature to C
protected meth decl_csignature(v: CompilerVisitor, args: Array[String]): String
do
var p = "val_t {args[i+1]}"
params.add(p)
end
+
+ var first_closure_index = signature.arity + 1 # Wich parameter is the first closure
+ for i in [0..signature.closures.length[ do
+ var closcn = closure_cname(i)
+ var cs = signature.closures[i].signature # Closure signature
+ var subparams = new Array[String] # Parameters of the closure
+ subparams.add("struct {closcn}*")
+ for j in [0..cs.arity[ do
+ var p = "val_t"
+ subparams.add(p)
+ end
+ var r = "void"
+ if cs.return_type != null then r = "val_t"
+ params.add("struct {closcn} *{args[first_closure_index+i]}")
+ v.add_decl("struct {closcn};")
+ v.add_decl("typedef {r} (*F{closcn})({subparams.join(", ")});")
+ v.add_decl("struct {closcn} \{F{closcn} fun; val_t *has_broke; val_t broke_value; val_t *variable; void **closurevariable;\};")
+ end
+
if global.is_init then
params.add("int* init_table")
end
+
var ret: String
if signature.return_type != null then
ret = "val_t"
else
ret = "void"
end
+
var p = params.join(", ")
var s = "{ret} {cname}({p})"
v.add_decl("typedef {ret} (* {cname}_t)({p});")
for i in [0..signature.arity[ do
args.add(" param{i}")
end
+ for i in [0..signature.closures.length[ do
+ args.add(" wd{i}")
+ end
var cs = decl_csignature(v, args)
v.add_decl("#define LOCATE_{cname} \"{full_name}\"")
var ctx_old = v.ctx
v.ctx = new CContext
+ v.out_contexts.clear
+
var ln = 0
var s = self
if s.node != null then ln = s.node.line_number
v.ctx = ctx_old
v.unindent
v.add_instr("}")
+
+ for ctx in v.out_contexts do v.ctx.merge(ctx)
end
# Compile the method body inline
meth do_compile_inside(v: CompilerVisitor, method: MMSrcMethod, params: Array[String]): String is abstract
end
+redef class PSignature
+ meth compile_parameters(v: CompilerVisitor, orig_sig: MMSignature, params: Array[String]) is abstract
+end
+
+redef class ASignature
+ redef meth compile_parameters(v: CompilerVisitor, orig_sig: MMSignature, params: Array[String])
+ do
+ for ap in n_params do
+ var cname = v.cfc.register_variable(ap.variable)
+ v.nmc.method_params.add(ap.variable)
+ var orig_type = orig_sig[ap.position]
+ if not orig_type < ap.variable.stype then
+ # FIXME: do not test always
+ # FIXME: handle formal types
+ v.add_instr("/* check if p<{ap.variable.stype} with p:{orig_type} */")
+ ap.variable.stype.compile_type_check(v, params[ap.position], ap)
+ end
+ v.add_assignment(cname, params[ap.position])
+ end
+ for i in [0..n_closure_decls.length[ do
+ var wd = n_closure_decls[i]
+ var cname = v.cfc.register_closurevariable(wd.variable)
+ wd.variable.ctypename = "struct {v.nmc.method.closure_cname(i)} *"
+ v.add_assignment(cname, "{params[orig_sig.arity + i]}")
+ end
+ end
+end
+
redef class AConcreteMethPropdef
redef meth do_compile_inside(v, method, params)
do
var old_nmc = v.nmc
v.nmc = new NitMethodContext(method)
- var cname = v.cfc.register_variable(self_var)
- v.add_assignment(cname, params[0])
+ var selfcname = v.cfc.register_variable(self_var)
+ v.add_assignment(selfcname, params[0])
+ params.shift
v.nmc.method_params = [self_var]
- var orig_meth: MMLocalProperty = method.global.intro
- var orig_sig = orig_meth.signature_for(method.signature.recv)
if n_signature != null then
- var sig = n_signature
- assert sig isa ASignature
- for ap in sig.n_params do
- var cname = v.cfc.register_variable(ap.variable)
- v.nmc.method_params.add(ap.variable)
- var orig_type = orig_sig[ap.position]
- if not orig_type < ap.variable.stype then
- # FIXME: do not test always
- # FIXME: handle formal types
- v.add_instr("/* check if p<{ap.variable.stype} with p:{orig_type} */")
- ap.variable.stype.compile_type_check(v, params[ap.position + 1], ap)
- end
- v.add_assignment(cname, params[ap.position + 1])
- end
+ var orig_meth: MMLocalProperty = method.global.intro
+ var orig_sig = orig_meth.signature_for(method.signature.recv)
+ n_signature.compile_parameters(v, orig_sig, params)
end
var itpos: String = null
if self isa AConcreteInitPropdef then
- itpos = "VAL2OBJ({params[0]})->vft[{method.local_class.global.init_table_pos_id}].i"
+ itpos = "VAL2OBJ({selfcname})->vft[{method.local_class.global.init_table_pos_id}].i"
# v.add_instr("printf(\"{method.full_name}: inittable[%d] = %d\\n\", {itpos}, init_table[{itpos}]);")
v.add_instr("if (init_table[{itpos}]) return;")
end
v.nmc.return_label = "return_label{v.new_number}"
- if method.signature.return_type != null then
- v.nmc.return_value = v.cfc.get_var
- v.cfc.free_var(v.nmc.return_value)
- else
- v.nmc.return_value = null
- end
+ v.nmc.return_value = v.cfc.get_var
if self isa AConcreteInitPropdef then
v.invoke_super_init_calls_after(null)
end
if n_block != null then
v.compile_stmt(n_block)
end
- if v.nmc.has_return then
- v.add_instr("{v.nmc.return_label}: while(false);")
- end
+ v.add_instr("{v.nmc.return_label}: while(false);")
if self isa AConcreteInitPropdef then
v.add_instr("init_table[{itpos}] = 1;")
end
- var ret = v.nmc.return_value
+
+ var ret: String = null
+ if method.signature.return_type != null then
+ ret = v.nmc.return_value
+ end
v.nmc = old_nmc
return ret
redef class AReturnExpr
redef meth compile_stmt(v)
do
- v.nmc.has_return = true
if n_expr != null then
var e = v.compile_expr(n_expr)
v.add_assignment(v.nmc.return_value, e)
end
+ if v.cfc.in_closure then v.add_instr("closctx->has_broke = &({v.nmc.return_value});")
v.add_instr("goto {v.nmc.return_label};")
end
end
redef class ABreakExpr
redef meth compile_stmt(v)
do
+ if n_expr != null then
+ var e = v.compile_expr(n_expr)
+ v.add_assignment(v.nmc.break_value, e)
+ end
+ if v.cfc.in_closure then v.add_instr("closctx->has_broke = &({v.nmc.break_value}); closctx->broke_value = *closctx->has_broke;")
v.add_instr("goto {v.nmc.break_label};")
end
end
redef class AContinueExpr
redef meth compile_stmt(v)
do
+ if n_expr != null then
+ var e = v.compile_expr(n_expr)
+ v.add_assignment(v.nmc.continue_value, e)
+ end
v.add_instr("goto {v.nmc.continue_label};")
end
end
redef meth compile_stmt(v)
do
var e = v.compile_expr(n_expr)
- var prop = n_expr.stype.local_class.select_method(once "iterator".to_symbol)
- if prop == null then
- printl("No iterator")
- return
- end
- var ittype = prop.signature.return_type
+ var ittype = meth_iterator.signature.return_type
v.cfc.free_var(e)
var iter = v.cfc.get_var
- v.add_assignment(iter, prop.compile_call(v, [e]))
- var prop2 = ittype.local_class.select_method(once "is_ok".to_symbol)
- if prop2 == null then
- printl("No is_ok")
- return
- end
- var prop3 = ittype.local_class.select_method(once "item".to_symbol)
- if prop3 == null then
- printl("No item")
- return
- end
- var prop4 = ittype.local_class.select_method(once "next".to_symbol)
- if prop4 == null then
- printl("No next")
- return
- end
+ v.add_assignment(iter, meth_iterator.compile_call(v, [e]))
v.add_instr("while (true) \{ /*for*/")
v.indent
var ok = v.cfc.get_var
- v.add_assignment(ok, prop2.compile_call(v, [iter]))
+ v.add_assignment(ok, meth_is_ok.compile_call(v, [iter]))
v.add_instr("if (!UNTAG_Bool({ok})) break; /*for*/")
v.cfc.free_var(ok)
- var e = prop3.compile_call(v, [iter])
+ var e = meth_item.compile_call(v, [iter])
e = v.ensure_var(e)
var cname = v.cfc.register_variable(variable)
v.add_assignment(cname, e)
v.compile_stmt(n_block)
end
v.add_instr("{v.nmc.continue_label}: while(0);")
- e = prop4.compile_call(v, [iter])
+ e = meth_next.compile_call(v, [iter])
assert e == null
v.unindent
v.add_instr("}")
redef class AStringFormExpr
redef meth compile_expr(v)
do
- var prop = stype.local_class.select_method(once "with_native".to_symbol)
compute_string_info
- return prop.compile_constructor_call(v, stype , ["BOX_NativeString(\"{_cstring}\")", "TAG_Int({_cstring_length})"])
+ return meth_with_native.compile_constructor_call(v, stype , ["BOX_NativeString(\"{_cstring}\")", "TAG_Int({_cstring_length})"])
end
# The raw string value
do
var len = 0
var str = string_text
- var res = new String
+ var res = new Buffer
var i = 0
while i < str.length do
var c = str[i]
res.add(c)
i = i + 1
end
- _cstring = res
+ _cstring = res.to_s
_cstring_length = len
end
end
redef class ASuperstringExpr
redef meth compile_expr(v)
do
- var prop = stype.local_class.select_method(once "init".to_symbol)
- var recv = prop.compile_constructor_call(v, stype, new Array[String])
-
- var prop2 = stype.local_class.select_method(once "append".to_symbol)
+ var array = meth_with_capacity.compile_constructor_call(v, atype, ["TAG_Int({n_exprs.length})"])
- var prop3 = stype.local_class.select_method(once "to_s".to_symbol)
for ne in n_exprs do
var e = v.ensure_var(v.compile_expr(ne))
if ne.stype != stype then
- v.add_assignment(e, prop3.compile_call(v, [e]))
+ v.add_assignment(e, meth_to_s.compile_call(v, [e]))
end
- prop2.compile_call(v, [recv, e])
+ meth_add.compile_call(v, [array, e])
end
- return recv
+ return meth_to_s.compile_call(v, [array])
end
end
redef class AArrayExpr
redef meth compile_expr(v)
do
- var prop = stype.local_class.select_method(once "with_capacity".to_symbol)
- var recv = prop.compile_constructor_call(v, stype, ["TAG_Int({n_exprs.length})"])
+ var recv = meth_with_capacity.compile_constructor_call(v, stype, ["TAG_Int({n_exprs.length})"])
- var prop2 = stype.local_class.select_method(once "add".to_symbol)
for ne in n_exprs do
var e = v.compile_expr(ne)
- prop2.compile_call(v, [recv, e])
+ meth_add.compile_call(v, [recv, e])
end
return recv
end
redef class ARangeExpr
redef meth compile_expr(v)
do
- var prop = stype.local_class.select_method(propname)
var e = v.compile_expr(n_expr)
var e2 = v.compile_expr(n_expr2)
- return prop.compile_constructor_call(v, stype, [e, e2])
+ return meth_init.compile_constructor_call(v, stype, [e, e2])
end
- # The constructor that must be used for the range
- protected meth propname: Symbol is abstract
-end
-
-redef class ACrangeExpr
- redef meth propname do return once "init".to_symbol
-end
-redef class AOrangeExpr
- redef meth propname do return once "without_last".to_symbol
end
redef class ASuperExpr
cargs.add(v.compile_expr(a))
end
- var e = prop.compile_call(v, cargs)
+ var e: String
+ if prop_signature.closures.is_empty then
+ e = prop.compile_call(v, cargs)
+ else
+ var cd = closure_defs
+ var arity = 0
+ if cd != null then arity = cd.length
+ var closcns = new Array[String]
+ var ve: String = null
+
+ # Prepare result value.
+ # In case of procedure, the return value is still used to intercept breaks
+ var old_bv = v.nmc.break_value
+ ve = v.cfc.get_var
+ v.nmc.break_value = ve
+
+ # Compile closure to c function
+ for i in [0..arity[ do
+ var cn = cd[i].compile_closure(v, prop.closure_cname(i))
+ closcns.add(cn)
+ cargs.add(cn)
+ end
+ for i in [arity..prop_signature.closures.length[ do
+ cargs.add("NULL")
+ end
+
+ v.nmc.break_value = old_bv
+
+ # Call
+ e = prop.compile_call(v, cargs)
+ if e != null then
+ v.add_assignment(ve, e)
+ e = ve
+ end
+
+ # Intercept returns and breaks
+ for i in [0..arity[ do
+ # A break or a return is intercepted
+ v.add_instr("if ({closcns[i]}->has_broke != NULL) \{")
+ v.indent
+ # A passtrought break or a return is intercepted: go the the next closure
+ v.add_instr("if ({closcns[i]}->has_broke != &({ve})) \{")
+ v.indent
+ if v.cfc.in_closure then v.add_instr("closctx->has_broke = {closcns[i]}->has_broke; closctx->broke_value = {closcns[i]}->broke_value;")
+ v.add_instr("goto {v.nmc.return_label};")
+ v.unindent
+ # A direct break is interpected
+ if e != null then
+ # overwrite the returned value in a function
+ v.add_instr("\} else {ve} = {closcns[i]}->broke_value;")
+ else
+ # Do nothing in a procedure
+ v.add_instr("\}")
+ end
+ v.unindent
+ v.add_instr("\}")
+ end
+ end
+
if prop.global.is_init then
v.invoke_super_init_calls_after(prop)
end
end
end
+redef class PClosureDef
+ # Compile the closure definition as a function in v.out_contexts
+ # Return the cname of the function
+ meth compile_closure(v: CompilerVisitor, closcn: String): String is abstract
+
+ # Compile the closure definition inside the current C function.
+ meth do_compile_inside(v: CompilerVisitor, params: Array[String]): String is abstract
+end
+
+redef class AClosureDef
+ # The cname of the function
+ readable attr _cname: String
+
+ redef meth compile_closure(v, closcn)
+ do
+ var ctx_old = v.ctx
+ v.ctx = new CContext
+ v.out_contexts.add(v.ctx)
+
+ var cfc_old = v.cfc.in_closure
+ v.cfc.in_closure = true
+
+ var old_rv = v.nmc.return_value
+ var old_bv = v.nmc.break_value
+ if not cfc_old then
+ v.nmc.return_value = "closctx->{old_rv}"
+ v.nmc.break_value = "closctx->{old_bv}"
+ end
+
+ var cname = "OC_{v.nmc.method.cname}_{v.out_contexts.length}"
+ _cname = cname
+ var args = new Array[String]
+ for i in [0..closure.signature.arity[ do
+ args.add(" param{i}")
+ end
+
+ var cs = decl_csignature(v, args, closcn)
+
+ v.add_instr("{cs} \{")
+ v.indent
+ var ctx_old2 = v.ctx
+ v.ctx = new CContext
+
+ v.add_decl("struct trace_t trace = \{NULL, NULL, {line_number}, LOCATE_{v.nmc.method.cname}};")
+ v.add_instr("trace.prev = tracehead; tracehead = &trace;")
+
+ v.add_instr("trace.file = LOCATE_{v.module.name};")
+ var s = do_compile_inside(v, args)
+
+ v.add_instr("{v.nmc.return_label}:")
+ v.add_instr("tracehead = trace.prev;")
+ if s == null then
+ v.add_instr("return;")
+ else
+ v.add_instr("return {s};")
+ end
+
+ ctx_old2.append(v.ctx)
+ v.ctx = ctx_old2
+ v.unindent
+ v.add_instr("}")
+ v.ctx = ctx_old
+
+ v.cfc.in_closure = cfc_old
+ v.nmc.return_value = old_rv
+ v.nmc.break_value = old_bv
+
+ # Build closure
+ var closcnv = "wbclos{v.new_number}"
+ v.add_decl("struct {closcn} {closcnv} = \{{cname}, NULL\};")
+ if cfc_old then
+ v.add_instr("{closcnv}.variable = closctx->variable;")
+ v.add_instr("{closcnv}.closurevariable = closctx->closurevariable;")
+ else
+ v.add_instr("{closcnv}.variable = variable;")
+ v.add_instr("{closcnv}.closurevariable = closurevariable;")
+ end
+
+ return "(&{closcnv})"
+ end
+
+ protected meth decl_csignature(v: CompilerVisitor, args: Array[String], closcn: String): String
+ do
+ var params = new Array[String]
+ params.add("struct {closcn}* closctx")
+ for i in [0..closure.signature.arity[ do
+ var p = "val_t {args[i]}"
+ params.add(p)
+ end
+ var ret: String
+ if closure.signature.return_type != null then
+ ret = "val_t"
+ else
+ ret = "void"
+ end
+ var p = params.join(", ")
+ var s = "{ret} {cname}({p})"
+ v.add_decl("struct {closcn};")
+ v.add_decl("typedef {ret} (* {cname}_t)({p});")
+ v.add_decl(s + ";")
+ return s
+ end
+
+ redef meth do_compile_inside(v, params)
+ do
+ for i in [0..variables.length[ do
+ var vacname = v.cfc.register_variable(variables[i])
+ v.add_assignment(vacname, params[i])
+ end
+
+ var old_cv = v.nmc.continue_value
+ var old_cl = v.nmc.continue_label
+ var old_bl = v.nmc.break_label
+
+ v.nmc.continue_value = v.cfc.get_var
+ v.nmc.continue_label = "continue_label{v.new_number}"
+ v.nmc.break_label = v.nmc.return_label
+
+ if n_expr != null then v.compile_stmt(n_expr)
+
+ v.add_instr("{v.nmc.continue_label}: while(false);")
+
+ var ret: String = null
+ if closure.signature.return_type != null then ret = v.nmc.continue_value
+
+ v.nmc.continue_value = old_cv
+ v.nmc.continue_label = old_cl
+ v.nmc.break_label = old_bl
+
+ return ret
+ end
+end
+
+redef class PClosureDecl
+ meth do_compile_inside(v: CompilerVisitor, params: Array[String]): String is abstract
+end
+redef class AClosureDecl
+ redef meth do_compile_inside(v, params)
+ do
+ if n_signature != null then n_signature.compile_parameters(v, variable.closure.signature, params)
+
+ var old_cv = v.nmc.continue_value
+ var old_cl = v.nmc.continue_label
+ var old_bl = v.nmc.break_label
+
+ v.nmc.continue_value = v.cfc.get_var
+ v.nmc.continue_label = "continue_label{v.new_number}"
+ v.nmc.break_label = v.nmc.return_label
+
+ if n_expr != null then v.compile_stmt(n_expr)
+
+ v.add_instr("{v.nmc.continue_label}: while(false);")
+
+ var ret: String = null
+ if variable.closure.signature.return_type != null then ret = v.nmc.continue_value
+
+ v.nmc.continue_value = old_cv
+ v.nmc.continue_label = old_cl
+ v.nmc.break_label = old_bl
+
+ return ret
+ end
+end
+
+redef class AClosureCallExpr
+ redef meth compile_expr(v)
+ do
+ var cargs = new Array[String]
+ for a in arguments do cargs.add(v.compile_expr(a))
+ var va: String = null
+ if variable.closure.signature.return_type != null then va = v.cfc.get_var
+
+ if variable.closure.is_optional then
+ v.add_instr("if({v.cfc.varname(variable)}==NULL) \{")
+ v.indent
+ var n = variable.decl
+ assert n isa AClosureDecl
+ var s = n.do_compile_inside(v, cargs)
+ if s != null then v.add_assignment(va, s)
+ v.unindent
+ v.add_instr("} else \{")
+ v.indent
+ end
+
+ var ivar = "(({variable.ctypename})({v.cfc.varname(variable)}))"
+ var cargs2 = [ivar]
+ cargs2.append(cargs)
+ var s = "({ivar}->fun({cargs2.join(", ")})) /* Invoke closure {variable} */"
+ if va != null then
+ v.add_assignment(va, s)
+ else
+ v.add_instr("{s};")
+ end
+ v.add_instr("if ({ivar}->has_broke) \{")
+ v.indent
+ if n_closure_defs != null and n_closure_defs.length == 1 then do
+ n_closure_defs.first.do_compile_inside(v, null)
+ end
+ if v.cfc.in_closure then v.add_instr("if ({ivar}->has_broke) \{ closctx->has_broke = {ivar}->has_broke; closctx->broke_value = {ivar}->broke_value;\}")
+ v.add_instr("goto {v.nmc.return_label};")
+ v.unindent
+ v.add_instr("\}")
+
+ if variable.closure.is_optional then
+ v.unindent
+ v.add_instr("\}")
+ end
+ return va
+ end
+end
+
redef class AProxyExpr
redef meth compile_expr(v)
do
nitlanguage / nit.git / blobdiff