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Prevent race and then infinite regress when initializing the root classes.

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Copied from Perforce
 Change: 190981
 ServerID: perforce.ravenbrook.com
This commit is contained in:
Richard Brooksby 2016-04-12 12:22:58 +01:00
parent 87aed22778
commit 21c319cd3b
1 changed files with 20 additions and 9 deletions
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29
mps/code/protocol.h
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@ -30,6 +30,8 @@
#define CLASS_INIT(ident) ident ## ClassInit
#define CLASS_CHECK(ident) ident ## ClassCheck
#define CLASS_SUPER(ident) ident ## SuperClassGet
#define CLASS_GUARDIAN(ident) ClassGuardian ## ident
#define CLASS_STATIC(ident) ClassStatic ## ident
#define KIND_CLASS(ident) ident ## Class
@ -48,18 +50,21 @@
#define DEFINE_CLASS(kind, ident, var) \
DECLARE_CLASS(kind, ident); \
static Bool CLASS_GUARDIAN(ident) = FALSE; \
static CLASS_STRUCT(kind) CLASS_STATIC(ident); \
CLASS_TYPE(kind) CLASS_ENSURE(ident)(void) \
{ \
static Bool guardian = FALSE; \
static CLASS_STRUCT(kind) classStruct; \
static CLASS_TYPE(kind) class = &classStruct; \
if (guardian == FALSE) { \
CLASS_TYPE(kind) class = &CLASS_STATIC(ident); \
if (CLASS_GUARDIAN(ident) == FALSE) { \
LockClaimGlobalRecursive(); \
if (guardian == FALSE) { \
guardian = TRUE; \
if (CLASS_GUARDIAN(ident) == FALSE) { \
CLASS_INIT(ident)(class); \
SetClassOfPoly(class, CLASS(KIND_CLASS(kind))); \
/* Prevent infinite regress. */ \
if (ClassId ## ident != ClassIdInstClass && \
ClassId ## ident != ClassIdInst) \
SetClassOfPoly(class, CLASS(KIND_CLASS(kind))); \
AVER(CLASS_CHECK(kind)(class)); \
CLASS_GUARDIAN(ident) = TRUE; \
} \
LockReleaseGlobalRecursive(); \
} \
@ -227,8 +232,14 @@ extern void InstFinish(Inst inst);
#define ClassOfPoly(kind, inst) \
MustBeA(KIND_CLASS(kind), MustBeA(Inst, inst)->class)
#define ClassName(class) RVALUE(((InstClass)(class))->name)
/* #define ClassName(class) RVALUE(MustBeA(InstClass, class)->name) */
/* ClassName -- get the human readable name of a class
*
* ClassName is used in describe methods and other unsafe places, so
* we don't use MustBeA.
*/
#define ClassName(class) RVALUE(CouldBeA(InstClass, class)->name)
/* SetClassOfPoly -- set the class of an object