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Fixed code that caused a seg-fault after parsing a (deferred) post-count argument followed by a (nested) function-call argument.

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The old broken code defers the count until the end of the (parent function's) argument list.  But, a nested function call clears the pointer to the deferred type.  That leads to an access violation.
The new code defers only until the end of each argument.  Fixes #1320.
This commit is contained in:
Greg King 2020-11-20 17:29:26 -05:00
parent 79bdc2d51f
commit 8b42f570e9
3 changed files with 34 additions and 37 deletions
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34
src/cc65/expr.c
View File

@ -1,7 +1,7 @@
/* expr.c
**
** 1998-06-21, Ullrich von Bassewitz
** 2020-01-25, Greg King
** 2020-11-20, Greg King
*/
@ -608,6 +608,8 @@ static unsigned FunctionParamList (FuncDesc* Func, int IsFastcall, ExprDesc* ED)
** The function returns the size of the arguments pushed in bytes.
*/
{
ExprDesc Expr;
/* Initialize variables */
SymEntry* Param = 0; /* Keep gcc silent */
unsigned PushedSize = 0; /* Size of arguments pushed */
@ -634,7 +636,6 @@ static unsigned FunctionParamList (FuncDesc* Func, int IsFastcall, ExprDesc* ED)
**
*/
if (ParamComplete && IS_Get (&CodeSizeFactor) >= 200) {
/* Calculate the number and size of the parameters */
FrameParams = Func->ParamCount;
FrameSize = Func->ParamSize;
@ -656,18 +657,13 @@ static unsigned FunctionParamList (FuncDesc* Func, int IsFastcall, ExprDesc* ED)
}
}
/* The info of the last argument could be needed out of the loop */
ExprDesc Expr;
ED_Init (&Expr);
Expr.Flags |= ED->Flags & E_MASK_KEEP_SUBEXPR;
/* Parse the actual argument list */
while (CurTok.Tok != TOK_RPAREN) {
unsigned Flags; /* Code generator flags, not expression flags */
/* This way the info of the last parameter won't be cleared */
ED_Init (&Expr);
/* This way, the info of the last parameter won't be cleared */
Expr.Flags |= ED->Flags & E_MASK_KEEP_SUBEXPR;
/* Count arguments */
@ -781,18 +777,20 @@ static unsigned FunctionParamList (FuncDesc* Func, int IsFastcall, ExprDesc* ED)
Error ("Argument expected after comma");
break;
}
DoDeferred (SQP_KEEP_NONE, &Expr);
}
/* Append last deferred inc/dec before the function is called.
** The last parameter needs to be preserved if it is passed in AX/EAX Regs.
*/
DoDeferred (IsFastcall ? SQP_KEEP_EAX : SQP_KEEP_NONE, &Expr);
/* Check if we had enough arguments */
if (PushedCount < Func->ParamCount) {
Error ("Too few arguments in function call");
}
/* Append deferred inc/dec before the function is called.
** The last parameter needs to be restored if it is passed with AX/EAX Regs.
*/
DoDeferred (IsFastcall ? SQP_KEEP_EAX : SQP_KEEP_NONE, &Expr);
/* The function returns the size of all arguments pushed onto the stack.
** However, if there are parameters missed (which is an error, and was
** flagged by the compiler), AND a stack frame was preallocated above,
@ -2025,8 +2023,8 @@ static void PostInc (ExprDesc* Expr)
/* Get the data type */
Flags = TypeOf (Expr->Type);
/* We are allowed by the C standard to defer the inc operation until
** the this expression is used, so that we don't need to save and reload
/* We are allowed by the C standard to defer the inc operation until after
** the expression is used, so that we don't need to save and reload
** the original value.
*/
@ -2065,7 +2063,7 @@ static void PostInc (ExprDesc* Expr)
/* Fetch the value and use it (since it's the result of the expression) */
LoadExpr (CF_NONE, Expr);
/* Defer the increment until the value of this expression is used */;
/* Defer the increment until after the value of this expression is used */
DeferInc (Expr);
}
}
@ -2132,7 +2130,7 @@ static void PostDec (ExprDesc* Expr)
/* Fetch the value and save it (since it's the result of the expression) */
LoadExpr (CF_NONE, Expr);
/* Defer the decrement until the value of this expression is used */;
/* Defer the decrement until after the value of this expression is used */
DeferDec (Expr);
}
}

6
test/misc/Makefile
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@ -100,12 +100,6 @@ $(WORKDIR)/bug1263.$1.$2.prg: bug1263.c | $(WORKDIR)
$(if $(QUIET),echo misc/bug1263.$1.$2.prg)
$(NOT) $(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLERR)
# should compile, but gives an error (segfault)
$(WORKDIR)/bug1320.$1.$2.prg: bug1320.c | $(WORKDIR)
@echo "FIXME: " $$@ "currently does not compile."
$(if $(QUIET),echo misc/bug1320.$1.$2.prg)
$(NOT) $(CC65) -t sim$2 -$1 -o $$@ $$< $(NULLERR)
# this one requires --std=c89, it fails with --std=c99
# it fails currently at runtime
$(WORKDIR)/bug1265.$1.$2.prg: bug1265.c | $(WORKDIR)

17
test/misc/bug1320.c → test/val/bug1320.c
View File

@ -1,5 +1,5 @@
/*
Copyright 2020 The cc65 Authors
Copyright 2020, The cc65 Authors
This software is provided "as-is", without any express or implied
warranty. In no event will the authors be held liable for any damages
@ -21,18 +21,23 @@
/*
Test of a post-counted pointer argument,
followed by a (nested) function-call argument.
Test that compiling it doesn't cause a seg-fault.
https://github.com/cc65/cc65/issues/1320
After the bug is fixed, this file should be moved to "test/val/".
*/
static char *var;
void foo (char *, char);
char bar (void);
static void foo (char *, char)
{
}
void main (void)
static char bar (void)
{
return 'b';
}
int main (void)
{
foo (var++, bar ());
return 0;