[dev.ssa] cmd/compile: Allow structs to be SSAd
Break small structs up into their components so they
can be registerized.
Change StructSelect to use field indexes instead of
field offsets, as field offsets aren't unique in the
presence of zero-sized fields.
Change-Id: I2f1dc89f7fa58e1cf58aa1a32b238959d53f62e4
Reviewed-on: https://go-review.googlesource.com/18570
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index 5c1a7af..107c145 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -335,10 +335,9 @@
{name: "GetClosurePtr"}, // get closure pointer from dedicated register
// Indexing operations
- {name: "ArrayIndex"}, // arg0=array, arg1=index. Returns a[i]
- {name: "PtrIndex"}, // arg0=ptr, arg1=index. Computes ptr+sizeof(*v.type)*index, where index is extended to ptrwidth type
- {name: "OffPtr"}, // arg0 + auxint (arg0 and result are pointers)
- {name: "StructSelect"}, // arg0=struct, auxint=field offset. Returns field at that offset (size=size of result type)
+ {name: "ArrayIndex"}, // arg0=array, arg1=index. Returns a[i]
+ {name: "PtrIndex"}, // arg0=ptr, arg1=index. Computes ptr+sizeof(*v.type)*index, where index is extended to ptrwidth type
+ {name: "OffPtr"}, // arg0 + auxint (arg0 and result are pointers)
// Slices
{name: "SliceMake"}, // arg0=ptr, arg1=len, arg2=cap
@@ -361,6 +360,14 @@
{name: "ITab", typ: "BytePtr"}, // arg0=interface, returns itable field
{name: "IData"}, // arg0=interface, returns data field
+ // Structs
+ {name: "StructMake0"}, // Returns struct with 0 fields.
+ {name: "StructMake1"}, // arg0=field0. Returns struct.
+ {name: "StructMake2"}, // arg0,arg1=field0,field1. Returns struct.
+ {name: "StructMake3"}, // arg0..2=field0..2. Returns struct.
+ {name: "StructMake4"}, // arg0..3=field0..3. Returns struct.
+ {name: "StructSelect"}, // arg0=struct, auxint=field index. Returns the auxint'th field.
+
// Spill&restore ops for the register allocator. These are
// semantically identical to OpCopy; they do not take/return
// stores like regular memory ops do. We can get away without memory
