rename spin-strict-memory to spin-relax-memory, and document it

Author: totalspectrum

backends/asm/outasm.c

@@ -31,7 +31,7 @@
 #define IS_FAST_CALL(f) ( (f == 0) || !FuncData(f) || FuncData(f)->convention == FAST_CALL)
 #define IS_STACK_CALL(f) ( (f != 0) && FuncData(f)->convention == STACK_CALL)
 
-#define ALL_VARS_ON_STACK(f) ( IS_STACK_CALL(f) || f->force_locals_to_stack || (f->local_address_taken && IsSpinLang(f->language) && !(f->optimize_flags & OPT_SPIN_STRICTMEM)) || f->closure)
+#define ALL_VARS_ON_STACK(f) ( IS_STACK_CALL(f) || f->force_locals_to_stack || (f->local_address_taken && IsSpinLang(f->language) && !(f->optimize_flags & OPT_SPIN_RELAXMEM)) || f->closure)
 #define ANY_VARS_ON_STACK(f) ( ALL_VARS_ON_STACK(f) || f->stack_local || f->local_address_taken )
 
 #define IS_LEAF(func) ((gl_compress == 0) && ((func)->is_leaf || (FuncData(func) && FuncData(func)->effectivelyLeaf)))

cmdline.c

@@ -538,7 +538,7 @@ static FlagTable optflag[] = {
     { "local-reuse", OPT_LOCAL_REUSE},
     { "aggressive-mem", OPT_AGGRESSIVE_MEM},
     { "cold-code", OPT_COLD_CODE},
-    { "spin-strict-memory", OPT_SPIN_STRICTMEM},
+    { "spin-relax-memory", OPT_SPIN_RELAXMEM},
     { "experimental", OPT_EXPERIMENTAL },
     { "all", OPT_FLAGS_ALL },
 };

doc/general.md

@@ -468,6 +468,10 @@ Moves unlikely code paths (indicated using `__builtin_expect`) to the end of the
 
 This optimization is not currently enabled by any flags. Use it cautiously.
 
+### Relax Spin memory semantics (-Ospin-relax-memory)
+
+Relaxes the Spin memory model. Normally if any local in a Spin function is put on the stack, all of the locals are; this allows for some common Spin idioms involving memory copies assuming that multiple variables may be copied. This option relaxes that and only puts variables on the stack if their addresses are explicitly taken.
+
 
 ## Memory Allocation and Management
 

frontends/common.h

@@ -193,10 +193,10 @@ extern int gl_optimize_flags; /* flags for optimization */
 #define OPT_AGGRESSIVE_MEM      0x00200000  /* aggressive load/store optimization */
 #define OPT_COLD_CODE           0x00400000  /* move cold code to end of function */
 #define OPT_MERGE_DUPLICATES    0x00800000  /* merge duplicate functions */
-#define OPT_SPIN_STRICTMEM      0x01000000  /* strict memory semantics for Spin */
+#define OPT_SPIN_RELAXMEM       0x01000000  /* relax strict memory semantics for Spin */
 
 #define OPT_EXPERIMENTAL        0x80000000  /* gate new or experimental optimizations */
-#define OPT_FLAGS_ALL           (0xffffffff & ~OPT_SPIN_STRICTMEM)
+#define OPT_FLAGS_ALL           0xffffffff
 
 #define OPT_ASM_BASIC  (OPT_BASIC_REGS|OPT_BRANCHES|OPT_PEEPHOLE|OPT_CONST_PROPAGATE|OPT_REMOVE_FEATURES|OPT_MAKE_MACROS)