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Adjust SP on gotos between blocks with local variables.

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This commit is contained in:
laubzega 2018-09-25 00:56:08 -07:00 committed by Oliver Schmidt
parent a48bbc4be0
commit 2ac2ffcd43
4 changed files with 62 additions and 4 deletions
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13
src/cc65/codegen.c
View File

@ -2425,6 +2425,19 @@ void g_falsejump (unsigned flags attribute ((unused)), unsigned label)
}
void g_lateadjustSP (unsigned label)
{
/* Adjust stack based on non-immediate data */
AddCodeLine ("pha");
AddCodeLine ("lda %s", LocalLabelName (label));
AddCodeLine ("clc");
AddCodeLine ("adc sp");
AddCodeLine ("sta sp");
AddCodeLine ("lda %s+1", LocalLabelName (label));
AddCodeLine ("adc sp+1");
AddCodeLine ("sta sp+1");
AddCodeLine ("pla");
}
void g_drop (unsigned Space)
/* Drop space allocated on the stack */

3
src/cc65/codegen.h
View File

@ -406,6 +406,9 @@ void g_truejump (unsigned flags, unsigned label);
void g_falsejump (unsigned flags, unsigned label);
/* Jump to label if zero flag set */
void g_lateadjustSP (unsigned label);
/* Adjust stack based on non-immediate data */
void g_drop (unsigned Space);
/* Drop space allocated on the stack */

3
src/cc65/symentry.h
View File

@ -107,6 +107,9 @@ struct DefOrRef {
unsigned Line;
long LocalsBlockNum;
unsigned Flags;
int StackPtr;
unsigned Depth;
unsigned LateSP_Label;
};
/* Symbol table entry */

45
src/cc65/symtab.c
View File

@ -670,6 +670,9 @@ DefOrRef* AddDefOrRef(SymEntry* E, unsigned Flags)
DOR->Line = GetCurrentLine ();
DOR->LocalsBlockNum = (long)CollLast (&CurrentFunc->LocalsBlockStack);
DOR->Flags = Flags;
DOR->StackPtr = StackPtr;
DOR->Depth = CollCount(&CurrentFunc->LocalsBlockStack);
DOR->LateSP_Label = GetLocalLabel();
return DOR;
}
@ -679,7 +682,8 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
/* Add a goto label to the label table */
{
unsigned i;
DefOrRef *DOR;
DefOrRef *DOR, *NewDOR;
/* Do we have an entry with this name already? */
SymEntry* Entry = FindSymInTable (LabelTab, Name, HashStr (Name));
if (Entry) {
@ -689,6 +693,8 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
Error ("Label `%s' is defined more than once", Name);
}
NewDOR = AddDefOrRef (Entry, Flags);
/* Walk through all occurrences of the label so far and check
if any of them is in a region that would be risky to jump from/to
from the place where we are right now. */
@ -698,13 +704,41 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
the one currently being added, i.e. if we are processing the
definition, we will only check the gotos; if we are processing
a goto statement, we will only look for the label definition. */
/*
if (((DOR->Flags & SC_DEF) != (Flags & SC_DEF)) &&
(CollCount(&CurrentFunc->LocalsBlockStack) == DOR->Depth) &&
(DOR->LocalsBlockNum != (long)CollLast (&CurrentFunc->LocalsBlockStack)))
Error ("Goto from line %d to label \'%s\' can result in a "
"trashed stack", Flags & SC_DEF ? DOR->Line : GetCurrentLine (), Name);
*/
if((DOR->Flags & SC_DEF) && (Flags & SC_REF)) {
/* We're processing a goto and here is its destination label.
This means the difference between SP values is also known, so
we simply emit SP adjustment code. */
if(StackPtr != DOR->StackPtr)
g_space(StackPtr - DOR->StackPtr);
if (CollCount(&CurrentFunc->LocalsBlockStack) <= DOR->Depth &&
DOR->LocalsBlockNum != (long)CollLast (&CurrentFunc->LocalsBlockStack)) {
Warning ("Goto from line %d to label \'%s\' can result in a "
"trashed stack", DOR->Line, Name);
}
}
AddDefOrRef (Entry, Flags);
if((DOR->Flags & SC_REF) && (Flags & SC_DEF)) {
/* We're processing a label, let's update all gotos encountered
so far */
g_defdatalabel(DOR->LateSP_Label);
g_defdata(CF_CONST | CF_INT, StackPtr - DOR->StackPtr, 0);
if (CollCount(&CurrentFunc->LocalsBlockStack) >= DOR->Depth &&
DOR->LocalsBlockNum != (long)CollLast (&CurrentFunc->LocalsBlockStack)) {
Warning ("Goto from line %d to label \'%s\' can result in a "
"trashed stack", DOR->Line, Name);
}
}
}
Entry->Flags |= Flags;
@ -718,7 +752,7 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
/* Create Collection for label definition and references */
Entry->V.L.DefsOrRefs = NewCollection ();
AddDefOrRef (Entry, Flags);
NewDOR = AddDefOrRef (Entry, Flags);
/* Generate the assembler name of the label */
Entry->AsmName = xstrdup (LocalLabelName (Entry->V.L.Label));
@ -728,6 +762,11 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
}
/* We are processing a goto, but the label has not yet been defined */
if (!SymIsDef (Entry) && (Flags & SC_REF)) {
g_lateadjustSP(NewDOR->LateSP_Label);
}
/* Return the entry */
return Entry;
}