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Proper warnings for "risky" gotos.

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This commit is contained in:
laubzega
2018-09-28 22:11:09 -07:00
committed by Oliver Schmidt
parent c835f49913
commit c797b3b376
10 changed files with 637 additions and 27 deletions
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3
src/cc65/function.c
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@@ -87,7 +87,6 @@ static Function* NewFunction (struct SymEntry* Sym)
F->TopLevelSP = 0;
F->RegOffs = RegisterSpace;
F->Flags = IsTypeVoid (F->ReturnType) ? FF_VOID_RETURN : FF_NONE;
F->LocalsBlockCount = 0;
InitCollection (&F->LocalsBlockStack);
@@ -524,6 +523,8 @@ void NewFunc (SymEntry* Func)
/* Need a starting curly brace */
ConsumeLCurly ();
/* Make sure there is always something on the stack of local variable blocks */
CollAppend (&CurrentFunc->LocalsBlockStack, 0);
/* Parse local variable declarations if any */

1
src/cc65/function.h
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@@ -61,7 +61,6 @@ struct Function {
int TopLevelSP; /* SP at function top level */
unsigned RegOffs; /* Register variable space offset */
funcflags_t Flags; /* Function flags */
long LocalsBlockCount; /* Number of blocks with local vars */
Collection LocalsBlockStack; /* Stack of blocks with local vars */
};

17
src/cc65/locals.c
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@@ -52,6 +52,7 @@
#include "standard.h"
#include "symtab.h"
#include "typeconv.h"
#include "input.h"
@@ -270,6 +271,12 @@ static void ParseAutoDecl (Declaration* Decl)
/* Mark the variable as referenced */
Sym->Flags |= SC_REF;
/* Make note of auto variables initialized in current block.
We abuse the Collection somewhat by using it to store line
numbers. */
CollReplace (&CurrentFunc->LocalsBlockStack, (void *)(long)GetCurrentLine (),
CollCount (&CurrentFunc->LocalsBlockStack) - 1);
} else {
/* Non-initialized local variable. Just keep track of
** the space needed.
@@ -489,6 +496,9 @@ void DeclareLocals (void)
/* Remember the current stack pointer */
int InitialStack = StackPtr;
/* A place to store info about potential initializations of auto variables */
CollAppend (&CurrentFunc->LocalsBlockStack, 0);
/* Loop until we don't find any more variables */
while (1) {
@@ -538,10 +548,9 @@ void DeclareLocals (void)
/* Be sure to allocate any reserved space for locals */
F_AllocLocalSpace (CurrentFunc);
if (InitialStack != StackPtr) {
++CurrentFunc->LocalsBlockCount;
/* Is it ok to abuse Collection in this way? */
CollAppend (&CurrentFunc->LocalsBlockStack, (void *)CurrentFunc->LocalsBlockCount);
/* No auto variables were inited. No new block on the stack then. */
if (CollLast (&CurrentFunc->LocalsBlockStack) == NULL) {
CollPop (&CurrentFunc->LocalsBlockStack);
}
/* In case we've allocated local variables in this block, emit a call to

5
src/cc65/stmt.c
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@@ -513,6 +513,7 @@ static int CompoundStatement (void)
/* Remember the stack at block entry */
int OldStack = StackPtr;
long OldBlockStackSize = CollCount (&CurrentFunc->LocalsBlockStack);
/* Enter a new lexical level */
EnterBlockLevel ();
@@ -535,7 +536,9 @@ static int CompoundStatement (void)
g_space (StackPtr - OldStack);
}
if (OldStack != StackPtr) {
/* If the segment had autoinited variables, let's pop it of a stack
of such blocks. */
if (OldBlockStackSize != CollCount (&CurrentFunc->LocalsBlockStack)) {
CollPop (&CurrentFunc->LocalsBlockStack);
}

2
src/cc65/symentry.c
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@@ -90,7 +90,7 @@ void FreeSymEntry (SymEntry* E)
if (E->Flags & SC_LABEL) {
for (i = 0; i < CollCount (E->V.L.DefsOrRefs); i++) {
xfree (CollAt(E->V.L.DefsOrRefs, i));
xfree (CollAt (E->V.L.DefsOrRefs, i));
}
DoneCollection (E->V.L.DefsOrRefs);

2
src/cc65/symentry.h
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@@ -105,7 +105,7 @@ struct LiteralPool;
typedef struct DefOrRef DefOrRef;
struct DefOrRef {
unsigned Line;
long LocalsBlockNum;
long LocalsBlockId;
unsigned Flags;
int StackPtr;
unsigned Depth;

42
src/cc65/symtab.c
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@@ -668,7 +668,7 @@ DefOrRef* AddDefOrRef(SymEntry* E, unsigned Flags)
DOR = xmalloc (sizeof (DefOrRef));
CollAppend (E->V.L.DefsOrRefs, DOR);
DOR->Line = GetCurrentLine ();
DOR->LocalsBlockNum = (long)CollLast (&CurrentFunc->LocalsBlockStack);
DOR->LocalsBlockId = (long)CollLast (&CurrentFunc->LocalsBlockStack);
DOR->Flags = Flags;
DOR->StackPtr = StackPtr;
DOR->Depth = CollCount (&CurrentFunc->LocalsBlockStack);
@@ -677,12 +677,13 @@ DefOrRef* AddDefOrRef(SymEntry* E, unsigned Flags)
return DOR;
}
SymEntry* AddLabelSym (const char* Name, unsigned Flags)
/* Add a goto label to the label table */
{
unsigned i;
DefOrRef *DOR, *NewDOR;
/* We juggle it so much that a shortcut will help with clarity */
Collection *AIC = &CurrentFunc->LocalsBlockStack;
/* Do we have an entry with this name already? */
SymEntry* Entry = FindSymInTable (LabelTab, Name, HashStr (Name));
@@ -700,35 +701,40 @@ SymEntry* AddLabelSym (const char* Name, unsigned Flags)
for (i = 0; i < CollCount (Entry->V.L.DefsOrRefs); i++) {
DOR = CollAt (Entry->V.L.DefsOrRefs, i);
if((DOR->Flags & SC_DEF) && (Flags & SC_REF)) {
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 already known,
so we simply emit the SP adjustment code. */
if(StackPtr != DOR->StackPtr)
if (StackPtr != DOR->StackPtr) {
g_space (StackPtr - DOR->StackPtr);
}
/* Are we jumping into same or deeper nesting region? That's risky,
so let's emit a warning. */
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);
/* Are we jumping into a block with initalization of an object that
has automatic storage duration? Let's emit a warning. */
if ((long)CollLast (AIC) != DOR->LocalsBlockId &&
(CollCount (AIC) < DOR->Depth ||
(long)CollAt (AIC, DOR->Depth - 1) != DOR->LocalsBlockId)) {
Warning ("Goto at line %d to label %s jumps into a block with "
"initialization of an object that has automatic storage duration.",
GetCurrentLine (), Name);
}
}
if((DOR->Flags & SC_REF) && (Flags & SC_DEF)) {
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);
/* Are we jumping into same or deeper nesting region? That's risky,
so let's emit a warning. */
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);
}
/* Are we jumping into a block with initalization of an object that
has automatic storage duration? Let's emit a warning. */
if ((long)CollLast (AIC) != DOR->LocalsBlockId &&
(CollCount (AIC) >= DOR->Depth ||
(long)CollLast (AIC) >= DOR->Line))
Warning ("Goto at line %d to label %s jumps into a block with "
"initialization of an object that has automatic storage duration.",
DOR->Line, Name);
}
}