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* factored out all the tests for whether we need to put inline parameters
in temps (no functional changes) git-svn-id: trunk@34286 -
This commit is contained in:
Jonas Maebe
parent
8d1e8ea203
commit
a3ca471d32
@ -4529,6 +4529,100 @@ implementation
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realtarget: tnode;
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paracomplexity: longint;
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pushconstaddr: boolean;
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function needtemp: boolean;
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begin
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{ We need a temp if the passed value will not be in memory, while
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the parameter inside the routine must be in memory }
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if (tparavarsym(para.parasym).varregable in [vr_none,vr_addr]) and
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not(para.left.expectloc in [LOC_REFERENCE,LOC_CREFERENCE]) then
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exit(true);
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{ We cannot create a formaldef temp and assign something to it }
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if para.parasym.vardef.typ=formaldef then
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exit(false);
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{ We try to handle complex expressions later by taking their address
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and storing this address in a temp (which is then dereferenced when
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the value is used; that doesn't work if we cannot take the address
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of the expression though, in which case we store the result of the
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expression in a temp }
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if (complexpara and not(para.left.expectloc in [LOC_REFERENCE,LOC_CREFERENCE]) or
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(complexpara and
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(not valid_for_addr(para.left,false) or
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(para.left.nodetype=calln) or
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is_constnode(para.left)))) then
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exit(true);
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{ Normally, we do not need to create a temp for value parameters that
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are not modified in the inlined function, and neither for const
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parameters that are passed by value.
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However, if we pass a global variable, an object field, a variable
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whose address has been taken, or an expression containing a pointer
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dereference as parameter, this value could be modified in other ways
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as well (even inside the callee) and in such cases we still create a
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temp to be on the safe side.
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We *must not* create a temp for global variables passed by
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reference to a const parameter, because if not inlined then any
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changes to the original value will also be visible in the callee
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(although this is technically undefined behaviour, since with
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"const" the programmer tells the compiler this argument will not
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change). }
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if (((para.parasym.varspez=vs_value) and
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(para.parasym.varstate in [vs_initialised,vs_declared,vs_read])) or
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((para.parasym.varspez=vs_const) and
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not pushconstaddr)) and
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foreachnodestatic(para.left,@nonlocalvars,pointer(symtableproc)) then
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exit(true);
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{ Value parameters of which we know they are modified by definition
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have to be copied to a temp; the same goes for cases of "x:=f(x)"
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where x is passed as value parameter to f(), at least if we
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optimized invocation by setting the funcretnode to x to avoid an
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assignment afterwards (since x may be read inside the function after
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it modified result==x) }
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if (para.parasym.varspez=vs_value) and
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(not(para.parasym.varstate in [vs_initialised,vs_declared,vs_read]) or
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(assigned(aktassignmentnode) and
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(aktassignmentnode.right=self) and
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(nf_assign_done_in_right in aktassignmentnode.flags) and
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actualtargetnode(@aktassignmentnode.left)^.isequal(actualtargetnode(@para.left)^))) then
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exit(true);
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{ the compiler expects that it can take the address of parameters passed by reference in
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the case of const so we can't replace the node simply by a constant node
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When playing with this code, ensure that
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function f(const a,b : longint) : longint;inline;
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begin
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result:=a*b;
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end;
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[...]
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...:=f(10,20));
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[...]
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is still folded. (FK)
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}
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if (para.parasym.varspez=vs_const) and
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{ const para's can get vs_readwritten if their address is taken ->
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in case they are not passed by reference, to keep the same
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behaviour as without inlining we have to make a copy in case the
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originally passed parameter value gets changed inside the callee
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}
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(not pushconstaddr and
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(para.parasym.varstate=vs_readwritten)
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) or
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{ call-by-reference const's may need to be passed by reference to
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function called in the inlined code }
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(pushconstaddr and
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not valid_for_addr(para.left,false)) then
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exit(true);
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result:=false;
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end;
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begin
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result:=false;
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{ determine how a parameter is passed to the inlined body
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@ -4553,15 +4647,15 @@ implementation
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pushconstaddr:=false;
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realtarget:=actualtargetnode(@para.left)^;
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{ if the parameter is "complex", try to take the address
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of the parameter expression, store it in a temp and replace
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occurrences of the parameter with dereferencings of this
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temp
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{ if the parameter is "complex", try to take the address of the
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parameter expression, store it in a temp and replace occurrences of
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the parameter with dereferencings of this temp
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}
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complexpara:=
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{ don't create a temp. for function results }
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not(nf_is_funcret in realtarget.flags) and
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{ this makes only sense if the parameter is reasonable complex else inserting directly is a better solution }
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{ this makes only sense if the parameter is reasonably complex,
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otherwise inserting directly is a better solution }
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(
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(paracomplexity>2) or
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{ don't create a temp. for the often seen case that p^ is passed to a var parameter }
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@ -4571,106 +4665,33 @@ implementation
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)
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);
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{ We don't need temps for parameters that are already temps, except if
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the passed temp could be put in a regvar while the parameter inside
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the routine cannot be (e.g., because its address is taken in the
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routine) }
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if (para.left.nodetype=temprefn) and
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(not(ti_may_be_in_reg in ttemprefnode(para.left).tempinfo^.flags) or
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not(tparavarsym(para.parasym).varregable in [vr_none,vr_addr])) then
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exit;
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{ check if we have to create a temp, assign the parameter's
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contents to that temp and then substitute the parameter
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with the temp everywhere in the function }
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if
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((tparavarsym(para.parasym).varregable in [vr_none,vr_addr]) and
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not(para.left.expectloc in [LOC_REFERENCE,LOC_CREFERENCE])) or
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{ we can't assign to formaldef temps }
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((para.parasym.vardef.typ<>formaldef) and
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(
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{ can we take the address of the argument? }
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(complexpara and not(para.left.expectloc in [LOC_REFERENCE,LOC_CREFERENCE])) or
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(complexpara and
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(not valid_for_addr(para.left,false) or
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(para.left.nodetype = calln) or
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is_constnode(para.left))) or
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{ we do not need to create a temp for value parameters }
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{ which are not modified in the inlined function }
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{ const parameters can get vs_readwritten if their }
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{ address is taken }
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((((para.parasym.varspez = vs_value) and
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(para.parasym.varstate in [vs_initialised,vs_declared,vs_read])) or
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{ in case of const, this is only necessary if the
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variable would be passed by value normally and if it is modified or if
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there is such a variable somewhere in an expression }
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((para.parasym.varspez = vs_const) and
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(not pushconstaddr))) and
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{ however, if we pass a global variable, an object field or}
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{ an expression containing a pointer dereference as }
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{ parameter, this value could be modified in other ways as }
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{ well and in such cases create a temp to be on the safe }
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{ side }
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foreachnodestatic(para.left,@nonlocalvars,pointer(symtableproc))) or
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{ value parameters of which we know they are modified by }
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{ definition have to be copied to a temp }
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{ the same goes for cases of "x:=f(x)" where x is passed }
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{ as value parameter to f(), at least if we optimized }
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{ invocation by setting the funcretnode to x to avoid }
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{ assignment afterwards (since x may be read inside the }
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{ function after it modified result==x) }
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((para.parasym.varspez = vs_value) and
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(not(para.parasym.varstate in [vs_initialised,vs_declared,vs_read]) or
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(assigned(aktassignmentnode) and
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(aktassignmentnode.right=self) and
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(nf_assign_done_in_right in aktassignmentnode.flags) and
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actualtargetnode(@aktassignmentnode.left)^.isequal(actualtargetnode(@para.left)^)))) or
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{ the compiler expects that it can take the address of parameters passed by reference in
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the case of const so we can't replace the node simply by a constant node
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When playing with this code, ensure that
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function f(const a,b : longint) : longint;inline;
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begin
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result:=a*b;
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end;
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[...]
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...:=f(10,20));
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[...]
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is still folded. (FK)
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}
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((para.parasym.varspez = vs_const) and
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{ const para's can get vs_readwritten if their address }
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{ is taken -> in case they are not passed by reference, }
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{ to keep the same behaviour as without inlining we have }
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{ to make a copy in case the originally passed parameter }
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{ value gets changed inside the callee }
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((not pushconstaddr and
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(para.parasym.varstate = vs_readwritten)
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) or
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{ call-by-reference const's may need to be passed by }
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{ reference to function called in the inlined code }
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(pushconstaddr and
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not valid_for_addr(para.left,false))
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)
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)
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)
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) then
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if needtemp then
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begin
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{ don't create a new temp unnecessarily, but make sure we
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do create a new one if the old one could be a regvar and
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the new one cannot be one }
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if not(tparavarsym(para.parasym).varspez in [vs_out,vs_var]) and (((para.left.nodetype<>temprefn) or
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(((tparavarsym(para.parasym).varregable in [vr_none,vr_addr])) and
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(ti_may_be_in_reg in ttemprefnode(para.left).tempinfo^.flags)))) then
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begin
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tempnode := ctempcreatenode.create(para.parasym.vardef,para.parasym.vardef.size,
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tt_persistent,tparavarsym(para.parasym).is_regvar(false));
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addstatement(inlineinitstatement,tempnode);
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tempnode:=ctempcreatenode.create(para.parasym.vardef,para.parasym.vardef.size,
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tt_persistent,tparavarsym(para.parasym).is_regvar(false));
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addstatement(inlineinitstatement,tempnode);
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if localvartrashing <> -1 then
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cnodeutils.maybe_trash_variable(inlineinitstatement,para.parasym,ctemprefnode.create(tempnode));
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addstatement(inlinecleanupstatement,ctempdeletenode.create(tempnode));
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addstatement(inlinecleanupstatement,ctempdeletenode.create(tempnode));
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addstatement(inlineinitstatement,cassignmentnode.create(ctemprefnode.create(tempnode),
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para.left));
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para.left := ctemprefnode.create(tempnode);
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{ inherit addr_taken flag }
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if (tabstractvarsym(para.parasym).addr_taken) then
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include(tempnode.tempinfo^.flags,ti_addr_taken);
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addstatement(inlineinitstatement,cassignmentnode.create(ctemprefnode.create(tempnode),
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para.left));
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para.left := ctemprefnode.create(tempnode);
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{ inherit addr_taken flag }
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if (tabstractvarsym(para.parasym).addr_taken) then
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include(tempnode.tempinfo^.flags,ti_addr_taken);
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end;
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result:=true;
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end
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end;
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