Auto merge of #37429 - camlorn:univariant_layout_optimization, r=eddyb

struct field reordering and optimization

This is work in progress.  The goal is to divorce the order of fields in source code from the order of fields in the LLVM IR, then optimize structs (and tuples/enum variants)by always ordering fields from least to most aligned.  It does not work yet.  I intend to check compiler memory usage as a benchmark, and a crater run will probably be required.

I don't know enough of the compiler to complete this work unaided.  If you see places that still need updating, please mention them.  The only one I know of currently is debuginfo, which I'm putting off intentionally until a bit later.

r? @eddyb

8 files changed, 19 insertions, 19 deletions

diff --git a/src/test/debuginfo/borrowed-enum.rs b/src/test/debuginfo/borrowed-enum.rs
index ddc29c64302..f34fc3b20d2 100644
--- a/src/test/debuginfo/borrowed-enum.rs
+++ b/src/test/debuginfo/borrowed-enum.rs
@@ -18,11 +18,11 @@
 // gdb-command:run
 
 // gdb-command:print *the_a_ref
-// gdbg-check:$1 = {{RUST$ENUM$DISR = TheA, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = TheA, __0 = 0, __1 = 2088533116, __2 = 2088533116}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = TheA, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = TheA, [...]}}
 // gdbr-check:$1 = borrowed_enum::ABC::TheA{x: 0, y: 8970181431921507452}
 
 // gdb-command:print *the_b_ref
-// gdbg-check:$2 = {{RUST$ENUM$DISR = TheB, x = 0, y = 1229782938247303441}, {RUST$ENUM$DISR = TheB, __0 = 0, __1 = 286331153, __2 = 286331153}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = TheB, [...]}, {RUST$ENUM$DISR = TheB, __0 = 0, __1 = 286331153, __2 = 286331153}}
 // gdbr-check:$2 = borrowed_enum::ABC::TheB(0, 286331153, 286331153)
 
 // gdb-command:print *univariant_ref
diff --git a/src/test/debuginfo/by-value-non-immediate-argument.rs b/src/test/debuginfo/by-value-non-immediate-argument.rs
index 6d821dbc155..0fe08c3a227 100644
--- a/src/test/debuginfo/by-value-non-immediate-argument.rs
+++ b/src/test/debuginfo/by-value-non-immediate-argument.rs
@@ -42,7 +42,7 @@
 // gdb-command:continue
 
 // gdb-command:print x
-// gdbg-check:$7 = {{RUST$ENUM$DISR = Case1, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 2088533116, __2 = 2088533116}}
+// gdbg-check:$7 = {{RUST$ENUM$DISR = Case1, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$7 = by_value_non_immediate_argument::Enum::Case1{x: 0, y: 8970181431921507452}
 // gdb-command:continue
 
diff --git a/src/test/debuginfo/generic-struct-style-enum.rs b/src/test/debuginfo/generic-struct-style-enum.rs
index dba9422721a..a328eec6893 100644
--- a/src/test/debuginfo/generic-struct-style-enum.rs
+++ b/src/test/debuginfo/generic-struct-style-enum.rs
@@ -17,15 +17,15 @@
 // gdb-command:run
 
 // gdb-command:print case1
-// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, a = 0, b = 31868, c = 31868, d = 31868, e = 31868}, {RUST$ENUM$DISR = Case1, a = 0, b = 2088533116, c = 2088533116}, {RUST$ENUM$DISR = Case1, a = 0, b = 8970181431921507452}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, a = 0, b = 31868, c = 31868, d = 31868, e = 31868}, {RUST$ENUM$DISR = Case1, [...]}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$1 = generic_struct_style_enum::Regular::Case1{a: 0, b: 31868, c: 31868, d: 31868, e: 31868}
 
 // gdb-command:print case2
-// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, a = 0, b = 4369, c = 4369, d = 4369, e = 4369}, {RUST$ENUM$DISR = Case2, a = 0, b = 286331153, c = 286331153}, {RUST$ENUM$DISR = Case2, a = 0, b = 1229782938247303441}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, [...]}, {RUST$ENUM$DISR = Case2, a = 0, b = 286331153, c = 286331153}, {RUST$ENUM$DISR = Case2, [...]}}
 // gdbr-check:$2 = generic_struct_style_enum::Regular::Case2{a: 0, b: 286331153, c: 286331153}
 
 // gdb-command:print case3
-// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, a = 0, b = 22873, c = 22873, d = 22873, e = 22873}, {RUST$ENUM$DISR = Case3, a = 0, b = 1499027801, c = 1499027801}, {RUST$ENUM$DISR = Case3, a = 0, b = 6438275382588823897}}
+// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, a = 0, b = 6438275382588823897}}
 // gdbr-check:$3 = generic_struct_style_enum::Regular::Case3{a: 0, b: 6438275382588823897}
 
 // gdb-command:print univariant
diff --git a/src/test/debuginfo/generic-tuple-style-enum.rs b/src/test/debuginfo/generic-tuple-style-enum.rs
index 01d2ff4e334..9ada5fdeff7 100644
--- a/src/test/debuginfo/generic-tuple-style-enum.rs
+++ b/src/test/debuginfo/generic-tuple-style-enum.rs
@@ -19,15 +19,15 @@
 // gdb-command:run
 
 // gdb-command:print case1
-// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = 31868, __2 = 31868, __3 = 31868, __4 = 31868}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 2088533116, __2 = 2088533116}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 8970181431921507452}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = 31868, __2 = 31868, __3 = 31868, __4 = 31868}, {RUST$ENUM$DISR = Case1, [...]}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$1 = generic_tuple_style_enum::Regular::Case1(0, 31868, 31868, 31868, 31868)
 
 // gdb-command:print case2
-// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, __0 = 0, __1 = 4369, __2 = 4369, __3 = 4369, __4 = 4369}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 286331153, __2 = 286331153}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 1229782938247303441}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, [...]}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 286331153, __2 = 286331153}, {RUST$ENUM$DISR = Case2, [...]}}
 // gdbr-check:$2 = generic_tuple_style_enum::Regular::Case2(0, 286331153, 286331153)
 
 // gdb-command:print case3
-// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, __0 = 0, __1 = 22873, __2 = 22873, __3 = 22873, __4 = 22873}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 1499027801, __2 = 1499027801}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 6438275382588823897}}
+// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 6438275382588823897}}
 // gdbr-check:$3 = generic_tuple_style_enum::Regular::Case3(0, 6438275382588823897)
 
 // gdb-command:print univariant
diff --git a/src/test/debuginfo/struct-in-enum.rs b/src/test/debuginfo/struct-in-enum.rs
index d0aceaa4f3f..ffd36ae14ad 100644
--- a/src/test/debuginfo/struct-in-enum.rs
+++ b/src/test/debuginfo/struct-in-enum.rs
@@ -19,11 +19,11 @@
 // gdb-command:run
 
 // gdb-command:print case1
-// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = {x = 2088533116, y = 2088533116, z = 31868}}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 8970181431921507452, __2 = 31868}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = {x = 2088533116, y = 2088533116, z = 31868}}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$1 = struct_in_enum::Regular::Case1(0, struct_in_enum::Struct {x: 2088533116, y: 2088533116, z: 31868})
 
 // gdb-command:print case2
-// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, __0 = 0, __1 = {x = 286331153, y = 286331153, z = 4369}}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 1229782938247303441, __2 = 4369}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, [...]}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 1229782938247303441, __2 = 4369}}
 // gdbr-check:$2 = struct_in_enum::Regular::Case2(0, 1229782938247303441, 4369)
 
 // gdb-command:print univariant
diff --git a/src/test/debuginfo/struct-style-enum.rs b/src/test/debuginfo/struct-style-enum.rs
index 8abc139eb11..b6196daaa46 100644
--- a/src/test/debuginfo/struct-style-enum.rs
+++ b/src/test/debuginfo/struct-style-enum.rs
@@ -19,15 +19,15 @@
 // gdb-command:run
 
 // gdb-command:print case1
-// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, a = 0, b = 31868, c = 31868, d = 31868, e = 31868}, {RUST$ENUM$DISR = Case1, a = 0, b = 2088533116, c = 2088533116}, {RUST$ENUM$DISR = Case1, a = 0, b = 8970181431921507452}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, a = 0, b = 31868, c = 31868, d = 31868, e = 31868}, {RUST$ENUM$DISR = Case1, [...]}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$1 = struct_style_enum::Regular::Case1{a: 0, b: 31868, c: 31868, d: 31868, e: 31868}
 
 // gdb-command:print case2
-// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, a = 0, b = 4369, c = 4369, d = 4369, e = 4369}, {RUST$ENUM$DISR = Case2, a = 0, b = 286331153, c = 286331153}, {RUST$ENUM$DISR = Case2, a = 0, b = 1229782938247303441}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, [...]}, {RUST$ENUM$DISR = Case2, a = 0, b = 286331153, c = 286331153}, {RUST$ENUM$DISR = Case2, [...]}}
 // gdbr-check:$2 = struct_style_enum::Regular::Case2{a: 0, b: 286331153, c: 286331153}
 
 // gdb-command:print case3
-// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, a = 0, b = 22873, c = 22873, d = 22873, e = 22873}, {RUST$ENUM$DISR = Case3, a = 0, b = 1499027801, c = 1499027801}, {RUST$ENUM$DISR = Case3, a = 0, b = 6438275382588823897}}
+// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, a = 0, b = 6438275382588823897}}
 // gdbr-check:$3 = struct_style_enum::Regular::Case3{a: 0, b: 6438275382588823897}
 
 // gdb-command:print univariant
diff --git a/src/test/debuginfo/tuple-style-enum.rs b/src/test/debuginfo/tuple-style-enum.rs
index d05edec3e73..988f223b3bc 100644
--- a/src/test/debuginfo/tuple-style-enum.rs
+++ b/src/test/debuginfo/tuple-style-enum.rs
@@ -19,15 +19,15 @@
 // gdb-command:run
 
 // gdb-command:print case1
-// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = 31868, __2 = 31868, __3 = 31868, __4 = 31868}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 2088533116, __2 = 2088533116}, {RUST$ENUM$DISR = Case1, __0 = 0, __1 = 8970181431921507452}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = Case1, __0 = 0, __1 = 31868, __2 = 31868, __3 = 31868, __4 = 31868}, {RUST$ENUM$DISR = Case1, [...]}, {RUST$ENUM$DISR = Case1, [...]}}
 // gdbr-check:$1 = tuple_style_enum::Regular::Case1(0, 31868, 31868, 31868, 31868)
 
 // gdb-command:print case2
-// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, __0 = 0, __1 = 4369, __2 = 4369, __3 = 4369, __4 = 4369}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 286331153, __2 = 286331153}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 1229782938247303441}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = Case2, [...]}, {RUST$ENUM$DISR = Case2, __0 = 0, __1 = 286331153, __2 = 286331153}, {RUST$ENUM$DISR = Case2, [...]}}
 // gdbr-check:$2 = tuple_style_enum::Regular::Case2(0, 286331153, 286331153)
 
 // gdb-command:print case3
-// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, __0 = 0, __1 = 22873, __2 = 22873, __3 = 22873, __4 = 22873}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 1499027801, __2 = 1499027801}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 6438275382588823897}}
+// gdbg-check:$3 = {{RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, [...]}, {RUST$ENUM$DISR = Case3, __0 = 0, __1 = 6438275382588823897}}
 // gdbr-check:$3 = tuple_style_enum::Regular::Case3(0, 6438275382588823897)
 
 // gdb-command:print univariant
diff --git a/src/test/debuginfo/unique-enum.rs b/src/test/debuginfo/unique-enum.rs
index e882544b802..cf8d90e30f1 100644
--- a/src/test/debuginfo/unique-enum.rs
+++ b/src/test/debuginfo/unique-enum.rs
@@ -18,11 +18,11 @@
 // gdb-command:run
 
 // gdb-command:print *the_a
-// gdbg-check:$1 = {{RUST$ENUM$DISR = TheA, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = TheA, __0 = 0, __1 = 2088533116, __2 = 2088533116}}
+// gdbg-check:$1 = {{RUST$ENUM$DISR = TheA, x = 0, y = 8970181431921507452}, {RUST$ENUM$DISR = TheA, [...]}}
 // gdbr-check:$1 = unique_enum::ABC::TheA{x: 0, y: 8970181431921507452}
 
 // gdb-command:print *the_b
-// gdbg-check:$2 = {{RUST$ENUM$DISR = TheB, x = 0, y = 1229782938247303441}, {RUST$ENUM$DISR = TheB, __0 = 0, __1 = 286331153, __2 = 286331153}}
+// gdbg-check:$2 = {{RUST$ENUM$DISR = TheB, [...]}, {RUST$ENUM$DISR = TheB, __0 = 0, __1 = 286331153, __2 = 286331153}}
 // gdbr-check:$2 = unique_enum::ABC::TheB(0, 286331153, 286331153)
 
 // gdb-command:print *univariant