copy elision using the ir system

Author: andrewrk

doc/langref.html.in

@@ -5855,13 +5855,13 @@ fn add(a: i32, b: i32) i32 { return a + b; }
       This function is a low level intrinsic with no safety mechanisms. Most code
       should not use this function, instead using something like this:
       </p>
-      <pre>{#syntax#}for (source[0...byte_count]) |b, i| dest[i] = b;{#endsyntax#}</pre>
+      <pre>{#syntax#}for (source[0..byte_count]) |b, i| dest[i] = b;{#endsyntax#}</pre>
       <p>
       The optimizer is intelligent enough to turn the above snippet into a memcpy.
       </p>
       <p>There is also a standard library function for this:</p>
       <pre>{#syntax#}const mem = @import("std").mem;
-mem.copy(u8, dest[0...byte_count], source[0...byte_count]);{#endsyntax#}</pre>
+mem.copy(u8, dest[0..byte_count], source[0..byte_count]);{#endsyntax#}</pre>
       {#header_close#}
       {#header_open|@memset#}
       <pre>{#syntax#}@memset(dest: [*]u8, c: u8, byte_count: usize){#endsyntax#}</pre>
@@ -5872,7 +5872,7 @@ mem.copy(u8, dest[0...byte_count], source[0...byte_count]);{#endsyntax#}</pre>
       This function is a low level intrinsic with no safety mechanisms. Most
       code should not use this function, instead using something like this:
       </p>
-      <pre>{#syntax#}for (dest[0...byte_count]) |*b| b.* = c;{#endsyntax#}</pre>
+      <pre>{#syntax#}for (dest[0..byte_count]) |*b| b.* = c;{#endsyntax#}</pre>
       <p>
       The optimizer is intelligent enough to turn the above snippet into a memset.
       </p>
@@ -6514,9 +6514,10 @@ pub const TypeInfo = union(TypeId).{
       {#code_end#}
       {#header_close#}
       {#header_open|@typeName#}
-      <pre>{#syntax#}@typeName(T: type) []u8{#endsyntax#}</pre>
+      <pre>{#syntax#}@typeName(T: type) [N]u8{#endsyntax#}</pre>
       <p>
-      This function returns the string representation of a type.
+      This function returns the string representation of a type, as
+      an array. It is equivalent to a string literal of the type name.
       </p>
 
       {#header_close#}

src/all_types.hpp

@@ -33,7 +33,7 @@ struct TypeStructField;
 struct CodeGen;
 struct ConstExprValue;
 struct IrInstruction;
-struct IrInstructionCast;
+struct IrInstructionAlloca;
 struct IrBasicBlock;
 struct ScopeDecls;
 struct ZigWindowsSDK;
@@ -68,6 +68,8 @@ struct IrExecutable {
     Scope *begin_scope;
     ZigList<Tld *> tld_list;
 
+    IrInstruction *return_result_loc;
+
     IrInstruction *coro_handle;
     IrInstruction *atomic_state_field_ptr; // this one is shared and in the promise
     IrInstruction *coro_result_ptr_field_ptr;
@@ -1320,7 +1322,7 @@ struct ZigFn {
     AstNode *fn_no_inline_set_node;
     AstNode *fn_static_eval_set_node;
 
-    ZigList<IrInstruction *> alloca_list;
+    ZigList<IrInstructionAlloca *> alloca_list;
     ZigList<ZigVar *> variable_list;
 
     Buf *section_name;
@@ -1885,6 +1887,7 @@ struct ScopeBlock {
     Buf *name;
     IrBasicBlock *end_block;
     IrInstruction *is_comptime;
+    IrInstruction *result_loc;
     ZigList<IrInstruction *> *incoming_values;
     ZigList<IrBasicBlock *> *incoming_blocks;
 
@@ -1937,6 +1940,7 @@ struct ScopeLoop {
     IrBasicBlock *break_block;
     IrBasicBlock *continue_block;
     IrInstruction *is_comptime;
+    IrInstruction *result_loc;
     ZigList<IrInstruction *> *incoming_values;
     ZigList<IrBasicBlock *> *incoming_blocks;
 };
@@ -2029,6 +2033,8 @@ struct IrBasicBlock {
 
 enum IrInstructionId {
     IrInstructionIdInvalid,
+    IrInstructionIdDeclVarSrc,
+    IrInstructionIdDeclVarGen,
     IrInstructionIdBr,
     IrInstructionIdCondBr,
     IrInstructionIdSwitchBr,
@@ -2037,7 +2043,6 @@ enum IrInstructionId {
     IrInstructionIdPhi,
     IrInstructionIdUnOp,
     IrInstructionIdBinOp,
-    IrInstructionIdDeclVar,
     IrInstructionIdLoadPtr,
     IrInstructionIdStorePtr,
     IrInstructionIdFieldPtr,
@@ -2166,9 +2171,16 @@ enum IrInstructionId {
     IrInstructionIdMarkErrRetTracePtr,
     IrInstructionIdSqrt,
     IrInstructionIdErrSetCast,
-    IrInstructionIdToBytes,
-    IrInstructionIdFromBytes,
     IrInstructionIdCheckRuntimeScope,
+    IrInstructionIdResultErrorUnionPayload,
+    IrInstructionIdResultReturn,
+    IrInstructionIdResultBytesToSlice,
+    IrInstructionIdResultSliceToBytes,
+    IrInstructionIdResultParam,
+    IrInstructionIdResultPtrCast,
+    IrInstructionIdLoadResult,
+    IrInstructionIdStoreResult,
+    IrInstructionIdAlloca,
 };
 
 struct IrInstruction {
@@ -2190,6 +2202,21 @@ struct IrInstruction {
     bool is_gen;
 };
 
+struct IrInstructionDeclVarSrc {
+    IrInstruction base;
+
+    ZigVar *var;
+    IrInstruction *var_type;
+    IrInstruction *align_value;
+    IrInstruction *ptr;
+};
+
+struct IrInstructionDeclVarGen {
+    IrInstruction base;
+
+    ZigVar *var;
+};
+
 struct IrInstructionCondBr {
     IrInstruction base;
 
@@ -2303,25 +2330,30 @@ struct IrInstructionBinOp {
     bool safety_check_on;
 };
 
-struct IrInstructionDeclVar {
+struct IrInstructionLoadPtr {
     IrInstruction base;
 
-    ZigVar *var;
-    IrInstruction *var_type;
-    IrInstruction *align_value;
-    IrInstruction *init_value;
+    IrInstruction *ptr;
 };
 
-struct IrInstructionLoadPtr {
+struct IrInstructionStorePtr {
     IrInstruction base;
 
     IrInstruction *ptr;
+    IrInstruction *value;
 };
 
-struct IrInstructionStorePtr {
+struct IrInstructionLoadResult {
     IrInstruction base;
 
     IrInstruction *ptr;
+    IrInstruction *result_loc;
+};
+
+struct IrInstructionStoreResult {
+    IrInstruction base;
+
+    IrInstruction *result_loc;
     IrInstruction *value;
 };
 
@@ -2374,13 +2406,12 @@ struct IrInstructionCall {
     ZigFn *fn_entry;
     size_t arg_count;
     IrInstruction **args;
-    bool is_comptime;
-    LLVMValueRef tmp_ptr;
-    FnInline fn_inline;
-    bool is_async;
-
     IrInstruction *async_allocator;
     IrInstruction *new_stack;
+    IrInstruction *result_loc;
+    FnInline fn_inline;
+    bool is_async;
+    bool is_comptime;
 };
 
 struct IrInstructionConst {
@@ -2401,23 +2432,24 @@ struct IrInstructionCast {
     IrInstruction base;
 
     IrInstruction *value;
+    IrInstruction *result_loc;
     ZigType *dest_type;
     CastOp cast_op;
-    LLVMValueRef tmp_ptr;
 };
 
 struct IrInstructionContainerInitList {
     IrInstruction base;
 
     IrInstruction *container_type;
+    IrInstruction *result_loc;
     size_t item_count;
     IrInstruction **items;
-    LLVMValueRef tmp_ptr;
 };
 
 struct IrInstructionContainerInitFieldsField {
     Buf *name;
     IrInstruction *value;
+    IrInstruction *result_loc;
     AstNode *source_node;
     TypeStructField *type_struct_field;
 };
@@ -2439,9 +2471,9 @@ struct IrInstructionStructInit {
     IrInstruction base;
 
     ZigType *struct_type;
+    IrInstruction *result_loc;
     size_t field_count;
     IrInstructionStructInitField *fields;
-    LLVMValueRef tmp_ptr;
 };
 
 struct IrInstructionUnionInit {
@@ -2450,7 +2482,7 @@ struct IrInstructionUnionInit {
     ZigType *union_type;
     TypeUnionField *field;
     IrInstruction *init_value;
-    LLVMValueRef tmp_ptr;
+    IrInstruction *result_loc;
 };
 
 struct IrInstructionUnreachable {
@@ -2523,9 +2555,9 @@ struct IrInstructionSliceType {
     IrInstruction base;
 
     IrInstruction *align_value;
+    IrInstruction *child_type;
     bool is_const;
     bool is_volatile;
-    IrInstruction *child_type;
 };
 
 struct IrInstructionAsm {
@@ -2600,7 +2632,7 @@ struct IrInstructionRef {
     IrInstruction base;
 
     IrInstruction *value;
-    LLVMValueRef tmp_ptr;
+    IrInstruction *result_loc;
     bool is_const;
     bool is_volatile;
 };
@@ -2662,15 +2694,14 @@ struct IrInstructionCmpxchg {
     IrInstruction *new_value;
     IrInstruction *success_order_value;
     IrInstruction *failure_order_value;
+    IrInstruction *result_loc;
 
     // if this instruction gets to runtime then we know these values:
     ZigType *type;
     AtomicOrder success_order;
     AtomicOrder failure_order;
 
     bool is_weak;
-
-    LLVMValueRef tmp_ptr;
 };
 
 struct IrInstructionFence {
@@ -2710,19 +2741,6 @@ struct IrInstructionErrSetCast {
     IrInstruction *target;
 };
 
-struct IrInstructionToBytes {
-    IrInstruction base;
-
-    IrInstruction *target;
-};
-
-struct IrInstructionFromBytes {
-    IrInstruction base;
-
-    IrInstruction *dest_child_type;
-    IrInstruction *target;
-};
-
 struct IrInstructionIntToFloat {
     IrInstruction base;
 
@@ -2778,8 +2796,8 @@ struct IrInstructionSlice {
     IrInstruction *ptr;
     IrInstruction *start;
     IrInstruction *end;
+    IrInstruction *result_loc;
     bool safety_check_on;
-    LLVMValueRef tmp_ptr;
 };
 
 struct IrInstructionMemberCount {
@@ -2867,21 +2885,21 @@ struct IrInstructionOptionalWrap {
     IrInstruction base;
 
     IrInstruction *value;
-    LLVMValueRef tmp_ptr;
+    IrInstruction *result_loc;
 };
 
 struct IrInstructionErrWrapPayload {
     IrInstruction base;
 
     IrInstruction *value;
-    LLVMValueRef tmp_ptr;
+    IrInstruction *result_loc;
 };
 
 struct IrInstructionErrWrapCode {
     IrInstruction base;
 
     IrInstruction *value;
-    LLVMValueRef tmp_ptr;
+    IrInstruction *result_loc;
 };
 
 struct IrInstructionFnProto {
@@ -2983,6 +3001,7 @@ struct IrInstructionTypeName {
     IrInstruction base;
 
     IrInstruction *type_value;
+    IrInstruction *result_loc;
 };
 
 enum LVal {
@@ -3007,6 +3026,7 @@ struct IrInstructionTagName {
     IrInstruction base;
 
     IrInstruction *target;
+    IrInstruction *result_loc;
 };
 
 struct IrInstructionTagType {
@@ -3264,6 +3284,49 @@ struct IrInstructionCheckRuntimeScope {
     IrInstruction *is_comptime;
 };
 
+struct IrInstructionResultErrorUnionPayload {
+    IrInstruction base;
+
+    IrInstruction *prev_result_loc;
+};
+
+struct IrInstructionResultBytesToSlice {
+    IrInstruction base;
+
+    IrInstruction *prev_result_loc;
+};
+
+struct IrInstructionResultSliceToBytes {
+    IrInstruction base;
+
+    IrInstruction *elem_type;
+    IrInstruction *prev_result_loc;
+};
+
+struct IrInstructionResultReturn {
+    IrInstruction base;
+};
+
+struct IrInstructionResultParam {
+    IrInstruction base;
+
+    IrInstruction *fn_ref;
+    size_t param_index;
+};
+
+struct IrInstructionResultPtrCast {
+    IrInstruction base;
+
+    IrInstruction *elem_type;
+    IrInstruction *prev_result_loc;
+};
+
+struct IrInstructionAlloca {
+    IrInstruction base;
+
+    IrInstruction *ty;
+};
+
 static const size_t slice_ptr_index = 0;
 static const size_t slice_len_index = 1;