Mass rename Ebb and relatives to Block (#1365)

* Manually rename BasicBlock to BlockPredecessor

BasicBlock is a pair of (Ebb, Inst) that is used to represent the
basic block subcomponent of an Ebb that is a predecessor to an Ebb.

Eventually we will be able to remove this struct, but for now it
makes sense to give it a non-conflicting name so that we can start
to transition Ebb to represent a basic block.

I have not updated any comments that refer to BasicBlock, as
eventually we will remove BlockPredecessor and replace with Block,
which is a basic block, so the comments will become correct.

* Manually rename SSABuilder block types to avoid conflict

SSABuilder has its own Block and BlockData types. These along with
associated identifier will cause conflicts in a later commit, so
they are renamed to be more verbose here.

* Automatically rename 'Ebb' to 'Block' in *.rs

* Automatically rename 'EBB' to 'block' in *.rs

* Automatically rename 'ebb' to 'block' in *.rs

* Automatically rename 'extended basic block' to 'basic block' in *.rs

* Automatically rename 'an basic block' to 'a basic block' in *.rs

* Manually update comment for `Block`

`Block`'s wikipedia article required an update.

* Automatically rename 'an `Block`' to 'a `Block`' in *.rs

* Automatically rename 'extended_basic_block' to 'basic_block' in *.rs

* Automatically rename 'ebb' to 'block' in *.clif

* Manually rename clif constant that contains 'ebb' as substring to avoid conflict

* Automatically rename filecheck uses of 'EBB' to 'BB'

'regex: EBB' -> 'regex: BB'
'$EBB' -> '$BB'

* Automatically rename 'EBB' 'Ebb' to 'block' in *.clif

* Automatically rename 'an block' to 'a block' in *.clif

* Fix broken testcase when function name length increases

Test function names are limited to 16 characters. This causes
the new longer name to be truncated and fail a filecheck test. An
outdated comment was also fixed.

cranelift/filetests/filetests/simple_gvn/basic.clif

@@ -1,7 +1,7 @@
 test simple-gvn
 
 function %simple_redundancy(i32, i32) -> i32 {
-ebb0(v0: i32, v1: i32):
+block0(v0: i32, v1: i32):
     v2 = iadd v0, v1
     v3 = iadd v0, v1
     v4 = imul v2, v3
@@ -10,7 +10,7 @@ ebb0(v0: i32, v1: i32):
 }
 
 function %cascading_redundancy(i32, i32) -> i32 {
-ebb0(v0: i32, v1: i32):
+block0(v0: i32, v1: i32):
     v2 = iadd v0, v1
     v3 = iadd v0, v1
     v4 = imul v2, v3
@@ -21,22 +21,22 @@ ebb0(v0: i32, v1: i32):
 }
 
 function %redundancies_on_some_paths(i32, i32, i32) -> i32 {
-ebb0(v0: i32, v1: i32, v2: i32):
+block0(v0: i32, v1: i32, v2: i32):
     v3 = iadd v0, v1
-    brz v3, ebb1
-    jump ebb3
+    brz v3, block1
+    jump block3
 
-ebb3:
+block3:
     v4 = iadd v0, v1
-    jump ebb2(v4)
-; check: jump ebb2(v3)
+    jump block2(v4)
+; check: jump block2(v3)
 
-ebb1:
+block1:
     v5 = iadd v0, v1
-    jump ebb2(v5)
-; check: jump ebb2(v3)
+    jump block2(v5)
+; check: jump block2(v3)
 
-ebb2(v6: i32):
+block2(v6: i32):
     v7 = iadd v0, v1
     v8 = iadd v6, v7
 ; check: v8 = iadd v6, v3

cranelift/filetests/filetests/simple_gvn/readonly.clif

@@ -7,7 +7,7 @@ function %eliminate_redundant_global_loads(i32, i64 vmctx) {
     gv1 = load.i64 notrap aligned readonly gv0
     heap0 = static gv1, min 0x1_0000, bound 0x1_0000_0000, offset_guard 0x8000_0000, index_type i32
 
-ebb0(v0: i32, v1: i64):
+block0(v0: i32, v1: i64):
     v2 = heap_addr.i64 heap0, v0, 1
     v3 = heap_addr.i64 heap0, v0, 1
 

cranelift/filetests/filetests/simple_gvn/reject.clif

@@ -1,7 +1,7 @@
 test simple-gvn
 
 function %other_side_effects(i32) -> i32 {
-ebb0(v0: i32):
+block0(v0: i32):
    regmove v0, %10 -> %20
    regmove v0, %10 -> %20
    regmove v0, %20 -> %10
@@ -11,7 +11,7 @@ ebb0(v0: i32):
 }
 
 function %differing_typevars() -> i64 {
-ebb0:
+block0:
     v0 = iconst.i32 7
     v1 = iconst.i64 7
     v2 = iconst.i64 8
@@ -25,7 +25,7 @@ ebb0:
 }
 
 function %cpu_flags() -> b1 {
-ebb0:
+block0:
     v0 = iconst.i32 7
     v1 = iconst.i32 8
     v2 = ifcmp v0, v1
@@ -41,7 +41,7 @@ ebb0:
 }
 
 function %spill() -> i32 {
-ebb0:
+block0:
     v0 = iconst.i32 7
     v1 = spill v0
     v2 = fill v1

cranelift/filetests/filetests/simple_gvn/scopes.clif

@@ -1,29 +1,29 @@
 test simple-gvn
 
 function %two_diamonds(i32, i32, i32, i32, i32) {
-ebb0(v0: i32, v1: i32, v2: i32, v3: i32, v4: i32):
+block0(v0: i32, v1: i32, v2: i32, v3: i32, v4: i32):
     v5 = iconst.i32 16
     ; check: v5 = iconst.i32 16
-    brz v0, ebb1
-    jump ebb5
+    brz v0, block1
+    jump block5
 
-ebb5:
+block5:
     v6 = iconst.i32 17
     ; check: v6 = iconst.i32 17
     v7 = iconst.i32 16
     ; not: v7 = iconst.i32 16
-    jump ebb2
+    jump block2
 
-ebb1:
+block1:
     v8 = iconst.i32 18
     ; check: v8 = iconst.i32 18
     v9 = iconst.i32 17
     ; check: v9 = iconst.i32 17
     v10 = iconst.i32 16
     ; not: v10 = iconst.i32 16
-    jump ebb2
+    jump block2
 
-ebb2:
+block2:
     v11 = iconst.i32 19
     ; check: v11 = iconst.i32 19
     v12 = iconst.i32 18
@@ -32,10 +32,10 @@ ebb2:
     ; check: v13 = iconst.i32 17
     v14 = iconst.i32 16
     ; not: v14 = iconst.i32 16
-    brz v1, ebb3
-    jump ebb6
+    brz v1, block3
+    jump block6
 
-ebb6:
+block6:
     v15 = iconst.i32 20
     ; check: v15 = iconst.i32 20
     v16 = iconst.i32 19
@@ -46,9 +46,9 @@ ebb6:
     ; not: v18 = iconst.i32 17
     v19 = iconst.i32 16
     ; not: v19 = iconst.i32 16
-    jump ebb4
+    jump block4
 
-ebb3:
+block3:
     v20 = iconst.i32 21
     ; check: v20 = iconst.i32 21
     v21 = iconst.i32 20
@@ -61,9 +61,9 @@ ebb3:
     ; not: v24 = iconst.i32 17
     v25 = iconst.i32 16
     ; not: v25 = iconst.i32 16
-    jump ebb4
+    jump block4
 
-ebb4:
+block4:
     v26 = iconst.i32 22
     ; check: v26 = iconst.i32 22
     v27 = iconst.i32 21