backport copy elision changes

This commit contains everything from the copy-elision-2
branch that does not have to do with copy elision directly,
but is generally useful for master branch.

 * All const values know their parents, when applicable, not
   just structs and unions.
 * Null pointers in const values are represented explicitly,
   rather than as a HardCodedAddr value of 0.
 * Rename "maybe" to "optional" in various code locations.
 * Separate DeclVarSrc and DeclVarGen
 * Separate PtrCastSrc and PtrCastGen
 * Separate CmpxchgSrc and CmpxchgGen
 * Represent optional error set as an integer, using the 0 value.
   In a const value, it uses nullptr.
 * Introduce type_has_one_possible_value and use it where applicable.
 * Fix debug builds not setting memory to 0xaa when storing
   undefined.
 * Separate the type of a variable from the const value of a variable.
 * Use copy_const_val where appropriate.
 * Rearrange structs to pack data more efficiently.
 * Move test/cases/* to test/behavior/*
 * Use `std.debug.assertOrPanic` in behavior tests instead of
   `std.debug.assert`.
 * Fix outdated slice syntax in docs.

1 files changed, 61 insertions, 22 deletions

diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index b5099db86a..a3ec8e9d35 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -172,7 +172,7 @@ static void ir_print_bin_op(IrPrint *irp, IrInstructionBinOp *bin_op_instruction
     }
 }
 
-static void ir_print_decl_var(IrPrint *irp, IrInstructionDeclVar *decl_var_instruction) {
+static void ir_print_decl_var_src(IrPrint *irp, IrInstructionDeclVarSrc *decl_var_instruction) {
     const char *var_or_const = decl_var_instruction->var->gen_is_const ? "const" : "var";
     const char *name = buf_ptr(&decl_var_instruction->var->name);
     if (decl_var_instruction->var_type) {
@@ -332,8 +332,8 @@ static void ir_print_var_ptr(IrPrint *irp, IrInstructionVarPtr *instruction) {
 }
 
 static void ir_print_load_ptr(IrPrint *irp, IrInstructionLoadPtr *instruction) {
-    fprintf(irp->f, "*");
     ir_print_other_instruction(irp, instruction->ptr);
+    fprintf(irp->f, ".*");
 }
 
 static void ir_print_store_ptr(IrPrint *irp, IrInstructionStorePtr *instruction) {
@@ -479,15 +479,15 @@ static void ir_print_size_of(IrPrint *irp, IrInstructionSizeOf *instruction) {
     fprintf(irp->f, ")");
 }
 
-static void ir_print_test_null(IrPrint *irp, IrInstructionTestNonNull *instruction) {
-    fprintf(irp->f, "*");
+static void ir_print_test_non_null(IrPrint *irp, IrInstructionTestNonNull *instruction) {
     ir_print_other_instruction(irp, instruction->value);
     fprintf(irp->f, " != null");
 }
 
-static void ir_print_unwrap_maybe(IrPrint *irp, IrInstructionUnwrapOptional *instruction) {
-    fprintf(irp->f, "&??*");
-    ir_print_other_instruction(irp, instruction->value);
+static void ir_print_optional_unwrap_ptr(IrPrint *irp, IrInstructionOptionalUnwrapPtr *instruction) {
+    fprintf(irp->f, "&");
+    ir_print_other_instruction(irp, instruction->base_ptr);
+    fprintf(irp->f, ".*.?");
     if (!instruction->safety_check_on) {
         fprintf(irp->f, " // no safety");
     }
@@ -613,7 +613,7 @@ static void ir_print_embed_file(IrPrint *irp, IrInstructionEmbedFile *instructio
     fprintf(irp->f, ")");
 }
 
-static void ir_print_cmpxchg(IrPrint *irp, IrInstructionCmpxchg *instruction) {
+static void ir_print_cmpxchg_src(IrPrint *irp, IrInstructionCmpxchgSrc *instruction) {
     fprintf(irp->f, "@cmpxchg(");
     ir_print_other_instruction(irp, instruction->ptr);
     fprintf(irp->f, ", ");
@@ -627,6 +627,16 @@ static void ir_print_cmpxchg(IrPrint *irp, IrInstructionCmpxchg *instruction) {
     fprintf(irp->f, ")");
 }
 
+static void ir_print_cmpxchg_gen(IrPrint *irp, IrInstructionCmpxchgGen *instruction) {
+    fprintf(irp->f, "@cmpxchg(");
+    ir_print_other_instruction(irp, instruction->ptr);
+    fprintf(irp->f, ", ");
+    ir_print_other_instruction(irp, instruction->cmp_value);
+    fprintf(irp->f, ", ");
+    ir_print_other_instruction(irp, instruction->new_value);
+    fprintf(irp->f, ", TODO print atomic orders)");
+}
+
 static void ir_print_fence(IrPrint *irp, IrInstructionFence *instruction) {
     fprintf(irp->f, "@fence(");
     ir_print_other_instruction(irp, instruction->order_value);
@@ -820,13 +830,13 @@ static void ir_print_test_err(IrPrint *irp, IrInstructionTestErr *instruction) {
 }
 
 static void ir_print_unwrap_err_code(IrPrint *irp, IrInstructionUnwrapErrCode *instruction) {
-    fprintf(irp->f, "@unwrapErrorCode(");
-    ir_print_other_instruction(irp, instruction->value);
+    fprintf(irp->f, "UnwrapErrorCode(");
+    ir_print_other_instruction(irp, instruction->err_union);
     fprintf(irp->f, ")");
 }
 
 static void ir_print_unwrap_err_payload(IrPrint *irp, IrInstructionUnwrapErrPayload *instruction) {
-    fprintf(irp->f, "@unwrapErrorPayload(");
+    fprintf(irp->f, "ErrorUnionFieldPayload(");
     ir_print_other_instruction(irp, instruction->value);
     fprintf(irp->f, ")");
     if (!instruction->safety_check_on) {
@@ -879,7 +889,7 @@ static void ir_print_test_comptime(IrPrint *irp, IrInstructionTestComptime *inst
     fprintf(irp->f, ")");
 }
 
-static void ir_print_ptr_cast(IrPrint *irp, IrInstructionPtrCast *instruction) {
+static void ir_print_ptr_cast_src(IrPrint *irp, IrInstructionPtrCastSrc *instruction) {
     fprintf(irp->f, "@ptrCast(");
     if (instruction->dest_type) {
         ir_print_other_instruction(irp, instruction->dest_type);
@@ -889,6 +899,12 @@ static void ir_print_ptr_cast(IrPrint *irp, IrInstructionPtrCast *instruction) {
     fprintf(irp->f, ")");
 }
 
+static void ir_print_ptr_cast_gen(IrPrint *irp, IrInstructionPtrCastGen *instruction) {
+    fprintf(irp->f, "@ptrCast(");
+    ir_print_other_instruction(irp, instruction->ptr);
+    fprintf(irp->f, ")");
+}
+
 static void ir_print_bit_cast(IrPrint *irp, IrInstructionBitCast *instruction) {
     fprintf(irp->f, "@bitCast(");
     if (instruction->dest_type) {
@@ -900,7 +916,7 @@ static void ir_print_bit_cast(IrPrint *irp, IrInstructionBitCast *instruction) {
 }
 
 static void ir_print_widen_or_shorten(IrPrint *irp, IrInstructionWidenOrShorten *instruction) {
-    fprintf(irp->f, "@widenOrShorten(");
+    fprintf(irp->f, "WidenOrShorten(");
     ir_print_other_instruction(irp, instruction->target);
     fprintf(irp->f, ")");
 }
@@ -1323,6 +1339,20 @@ static void ir_print_sqrt(IrPrint *irp, IrInstructionSqrt *instruction) {
     fprintf(irp->f, ")");
 }
 
+static void ir_print_decl_var_gen(IrPrint *irp, IrInstructionDeclVarGen *decl_var_instruction) {
+    ZigVar *var = decl_var_instruction->var;
+    const char *var_or_const = decl_var_instruction->var->gen_is_const ? "const" : "var";
+    const char *name = buf_ptr(&decl_var_instruction->var->name);
+    fprintf(irp->f, "%s %s: %s align(%u) = ", var_or_const, name, buf_ptr(&var->var_type->name),
+            var->align_bytes);
+
+    ir_print_other_instruction(irp, decl_var_instruction->init_value);
+    if (decl_var_instruction->var->is_comptime != nullptr) {
+        fprintf(irp->f, " // comptime = ");
+        ir_print_other_instruction(irp, decl_var_instruction->var->is_comptime);
+    }
+}
+
 static void ir_print_bswap(IrPrint *irp, IrInstructionBswap *instruction) {
     fprintf(irp->f, "@bswap(");
     if (instruction->type != nullptr) {
@@ -1361,8 +1391,8 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
         case IrInstructionIdBinOp:
             ir_print_bin_op(irp, (IrInstructionBinOp *)instruction);
             break;
-        case IrInstructionIdDeclVar:
-            ir_print_decl_var(irp, (IrInstructionDeclVar *)instruction);
+        case IrInstructionIdDeclVarSrc:
+            ir_print_decl_var_src(irp, (IrInstructionDeclVarSrc *)instruction);
             break;
         case IrInstructionIdCast:
             ir_print_cast(irp, (IrInstructionCast *)instruction);
@@ -1452,10 +1482,10 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
             ir_print_size_of(irp, (IrInstructionSizeOf *)instruction);
             break;
         case IrInstructionIdTestNonNull:
-            ir_print_test_null(irp, (IrInstructionTestNonNull *)instruction);
+            ir_print_test_non_null(irp, (IrInstructionTestNonNull *)instruction);
             break;
-        case IrInstructionIdUnwrapOptional:
-            ir_print_unwrap_maybe(irp, (IrInstructionUnwrapOptional *)instruction);
+        case IrInstructionIdOptionalUnwrapPtr:
+            ir_print_optional_unwrap_ptr(irp, (IrInstructionOptionalUnwrapPtr *)instruction);
             break;
         case IrInstructionIdCtz:
             ir_print_ctz(irp, (IrInstructionCtz *)instruction);
@@ -1508,8 +1538,11 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
         case IrInstructionIdEmbedFile:
             ir_print_embed_file(irp, (IrInstructionEmbedFile *)instruction);
             break;
-        case IrInstructionIdCmpxchg:
-            ir_print_cmpxchg(irp, (IrInstructionCmpxchg *)instruction);
+        case IrInstructionIdCmpxchgSrc:
+            ir_print_cmpxchg_src(irp, (IrInstructionCmpxchgSrc *)instruction);
+            break;
+        case IrInstructionIdCmpxchgGen:
+            ir_print_cmpxchg_gen(irp, (IrInstructionCmpxchgGen *)instruction);
             break;
         case IrInstructionIdFence:
             ir_print_fence(irp, (IrInstructionFence *)instruction);
@@ -1607,8 +1640,11 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
         case IrInstructionIdTestComptime:
             ir_print_test_comptime(irp, (IrInstructionTestComptime *)instruction);
             break;
-        case IrInstructionIdPtrCast:
-            ir_print_ptr_cast(irp, (IrInstructionPtrCast *)instruction);
+        case IrInstructionIdPtrCastSrc:
+            ir_print_ptr_cast_src(irp, (IrInstructionPtrCastSrc *)instruction);
+            break;
+        case IrInstructionIdPtrCastGen:
+            ir_print_ptr_cast_gen(irp, (IrInstructionPtrCastGen *)instruction);
             break;
         case IrInstructionIdBitCast:
             ir_print_bit_cast(irp, (IrInstructionBitCast *)instruction);
@@ -1775,6 +1811,9 @@ static void ir_print_instruction(IrPrint *irp, IrInstruction *instruction) {
         case IrInstructionIdCheckRuntimeScope:
             ir_print_check_runtime_scope(irp, (IrInstructionCheckRuntimeScope *)instruction);
             break;
+        case IrInstructionIdDeclVarGen:
+            ir_print_decl_var_gen(irp, (IrInstructionDeclVarGen *)instruction);
+            break;
     }
     fprintf(irp->f, "\n");
 }