[WebAssembly] Make disassembler always emit most canonical name.

Summary:
There are a few instructions that all map to the same opcode, so
when disassembling, we have to pick one. That was just the first one
before (the except_ref variant in the case of "call"), now it is the
one marked as IsCanonical in tablegen, or failing that, the shortest
name (which is typically the "canonical" one).

Also introduced a canonical "end" instruction for this purpose.

Reviewers: dschuff, tlively

Subscribers: sbc100, jgravelle-google, aheejin, llvm-commits, sunfish

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57713

llvm-svn: 353131

4 files changed, 22 insertions, 11 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrCall.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrCall.td
index a4efa85aadf..6b7c9b24ddc 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrCall.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrCall.td
@@ -93,17 +93,18 @@ let Uses = [SP32, SP64], isCall = 1 in {
   defm "" : SIMD_CALL<v4f32, "v128.">;
   defm "" : SIMD_CALL<v2f64, "v128.">;
 
+  let IsCanonical = 1 in {
   defm CALL_VOID : I<(outs), (ins function32_op:$callee, variable_ops),
-                     (outs), (ins function32_op:$callee),
-                     [(WebAssemblycall0 (i32 imm:$callee))],
-                     "call    \t$callee", "call\t$callee", 0x10>;
+                    (outs), (ins function32_op:$callee),
+                    [(WebAssemblycall0 (i32 imm:$callee))],
+                    "call    \t$callee", "call\t$callee", 0x10>;
 
   let isCodeGenOnly = 1 in {
     defm PCALL_INDIRECT_VOID : I<(outs), (ins I32:$callee, variable_ops),
-                                 (outs), (ins I32:$callee),
-                                 [(WebAssemblycall0 I32:$callee)],
-                                 "PSEUDO CALL INDIRECT\t$callee",
-                                 "PSEUDO CALL INDIRECT\t$callee">;
+                                (outs), (ins I32:$callee),
+                                [(WebAssemblycall0 I32:$callee)],
+                                "PSEUDO CALL INDIRECT\t$callee",
+                                "PSEUDO CALL INDIRECT\t$callee">;
   } // isCodeGenOnly = 1
 
   defm CALL_INDIRECT_VOID : I<(outs),
@@ -113,6 +114,7 @@ let Uses = [SP32, SP64], isCall = 1 in {
                               [],
                               "call_indirect\t", "call_indirect\t$type",
                               0x11>;
+  }
 } // Uses = [SP32,SP64], isCall = 1
 
 // Patterns for matching a direct call to a global address.
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
index 8160cab7520..59faeb88c5e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
@@ -81,6 +81,10 @@ defm ELSE : NRI<(outs), (ins), [], "else", 0x05>;
 defm END_BLOCK : NRI<(outs), (ins), [], "end_block", 0x0b>;
 defm END_LOOP  : NRI<(outs), (ins), [], "end_loop", 0x0b>;
 defm END_IF    : NRI<(outs), (ins), [], "end_if", 0x0b>;
+// Generic instruction, for disassembler.
+let IsCanonical = 1 in {
+defm END       : NRI<(outs), (ins), [], "end", 0x0b>;
+}
 let isTerminator = 1, isBarrier = 1 in
 defm END_FUNCTION : NRI<(outs), (ins), [], "end_function", 0x0b>;
 } // Uses = [VALUE_STACK], Defs = [VALUE_STACK]
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrFormats.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrFormats.td
index 2a2c79c56d6..aff4d20d8d8 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrFormats.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrFormats.td
@@ -22,6 +22,9 @@ class WebAssemblyInst<bits<32> inst, string asmstr, string stack> : StackRel,
   let Namespace   = "WebAssembly";
   let Pattern     = [];
   let AsmString   = asmstr;
+  // When there are multiple instructions that map to the same encoding (in
+  // e.g. the disassembler use case) prefer the one where IsCanonical == 1.
+  bit IsCanonical = 0;
 }
 
 // Normal instructions. Default instantiation of a WebAssemblyInst.
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
index ab0f48c9a1e..71c469d755b 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
@@ -125,12 +125,14 @@ defm "" : ConstVec<v8i16,
                      ImmI16:$i0, ImmI16:$i1, ImmI16:$i2, ImmI16:$i3,
                      ImmI16:$i4, ImmI16:$i5, ImmI16:$i6, ImmI16:$i7),
                    "$i0, $i1, $i2, $i3, $i4, $i5, $i6, $i7">;
+let IsCanonical = 1 in {
 defm "" : ConstVec<v4i32,
-                   (ins vec_i32imm_op:$i0, vec_i32imm_op:$i1,
+                  (ins vec_i32imm_op:$i0, vec_i32imm_op:$i1,
                         vec_i32imm_op:$i2, vec_i32imm_op:$i3),
-                   (build_vector (i32 imm:$i0), (i32 imm:$i1),
-                                 (i32 imm:$i2), (i32 imm:$i3)),
-                   "$i0, $i1, $i2, $i3">;
+                  (build_vector (i32 imm:$i0), (i32 imm:$i1),
+                                (i32 imm:$i2), (i32 imm:$i3)),
+                  "$i0, $i1, $i2, $i3">;
+}
 defm "" : ConstVec<v2i64,
                    (ins vec_i64imm_op:$i0, vec_i64imm_op:$i1),
                    (build_vector (i64 imm:$i0), (i64 imm:$i1)),