[WebAssembly] Use 'any' type in more cases in AsmTypeCheck

Now that we support 'any' type in the value stack in the checker, this
uses it in more places.

When an instruction pops multiple values, rather than popping in one by
one and generating multiple error messages, it adds them to a vector and
pops them at once. When the type to be popped is not clear, it pops
'any', at least makes sure there are correct number of values on the
stack. So for example, in case of `table.fill`, which expects `[i32 t
i32]` (where t is the type of the elements in the table), it pops them
at once, generating an error message like
```console
error: type mismatch, expected [i32, externref, i32] but got [...]
```
In case the table is invalid so we don't know the type, it tries to pop
an 'any' instead, popping whatever value there is:
```console
error: type mismatch, expected [i32, any, i32] but got [...]
```

Checks done on other instructions based on the register info are already
popping and pushing types in vectors, after llvm#110094:
https://github.com/llvm/llvm-project/blob/a52251675f001115b225f57362d37e92b7355ef9/llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmTypeCheck.cpp#L515-L536

This also pushes 'any' in case the type to push is unclear. For example,
`local/global.set` pushes a value of the type specified in the local or
global, but in case that local or global is invalid, we push 'any'
instead, which will match with whatever type.

The objective of all these is not to make one instruction's error
propragate continuously into subsequent instructions. This also matches
Wabt's behavior.

This also renames `checkAndPopTypes` to just `popTypes`, to be
consistent with a single-element version `popType`. `popType(s)` also
does type checks.

Author: aheejin

llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmTypeCheck.cpp

@@ -19,6 +19,7 @@
 #include "MCTargetDesc/WebAssemblyTargetStreamer.h"
 #include "TargetInfo/WebAssemblyTargetInfo.h"
 #include "WebAssembly.h"
+#include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
@@ -159,15 +160,15 @@ bool WebAssemblyAsmTypeCheck::checkTypes(SMLoc ErrorLoc,
                                  getTypesString(Stack, StackStartPos));
 }
 
-bool WebAssemblyAsmTypeCheck::checkAndPopTypes(SMLoc ErrorLoc,
-                                               ArrayRef<wasm::ValType> ValTypes,
-                                               bool ExactMatch) {
-  return checkAndPopTypes(ErrorLoc, valTypeToStackType(ValTypes), ExactMatch);
+bool WebAssemblyAsmTypeCheck::popTypes(SMLoc ErrorLoc,
+                                       ArrayRef<wasm::ValType> ValTypes,
+                                       bool ExactMatch) {
+  return popTypes(ErrorLoc, valTypeToStackType(ValTypes), ExactMatch);
 }
 
-bool WebAssemblyAsmTypeCheck::checkAndPopTypes(SMLoc ErrorLoc,
-                                               ArrayRef<StackType> Types,
-                                               bool ExactMatch) {
+bool WebAssemblyAsmTypeCheck::popTypes(SMLoc ErrorLoc,
+                                       ArrayRef<StackType> Types,
+                                       bool ExactMatch) {
   bool Error = checkTypes(ErrorLoc, Types, ExactMatch);
   auto NumPops = std::min(Stack.size(), Types.size());
   for (size_t I = 0, E = NumPops; I != E; I++)
@@ -176,7 +177,7 @@ bool WebAssemblyAsmTypeCheck::checkAndPopTypes(SMLoc ErrorLoc,
 }
 
 bool WebAssemblyAsmTypeCheck::popType(SMLoc ErrorLoc, StackType Type) {
-  return checkAndPopTypes(ErrorLoc, {Type}, false);
+  return popTypes(ErrorLoc, {Type});
 }
 
 bool WebAssemblyAsmTypeCheck::popRefType(SMLoc ErrorLoc) {
@@ -207,7 +208,7 @@ bool WebAssemblyAsmTypeCheck::checkBr(SMLoc ErrorLoc, size_t Level) {
                      StringRef("br: invalid depth ") + std::to_string(Level));
   const SmallVector<wasm::ValType, 4> &Expected =
       BrStack[BrStack.size() - Level - 1];
-  return checkTypes(ErrorLoc, Expected, false);
+  return checkTypes(ErrorLoc, Expected);
   return false;
 }
 
@@ -216,13 +217,13 @@ bool WebAssemblyAsmTypeCheck::checkEnd(SMLoc ErrorLoc, bool PopVals) {
     BrStack.pop_back();
 
   if (PopVals)
-    return checkAndPopTypes(ErrorLoc, LastSig.Returns, false);
-  return checkTypes(ErrorLoc, LastSig.Returns, false);
+    return popTypes(ErrorLoc, LastSig.Returns);
+  return checkTypes(ErrorLoc, LastSig.Returns);
 }
 
 bool WebAssemblyAsmTypeCheck::checkSig(SMLoc ErrorLoc,
                                        const wasm::WasmSignature &Sig) {
-  bool Error = checkAndPopTypes(ErrorLoc, Sig.Params, false);
+  bool Error = popTypes(ErrorLoc, Sig.Params);
   pushTypes(Sig.Returns);
   return Error;
 }
@@ -309,7 +310,7 @@ bool WebAssemblyAsmTypeCheck::getSignature(SMLoc ErrorLoc,
 }
 
 bool WebAssemblyAsmTypeCheck::endOfFunction(SMLoc ErrorLoc, bool ExactMatch) {
-  bool Error = checkAndPopTypes(ErrorLoc, ReturnTypes, ExactMatch);
+  bool Error = popTypes(ErrorLoc, ReturnTypes, ExactMatch);
   Unreachable = true;
   return Error;
 }
@@ -326,12 +327,14 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
       pushType(Type);
       return false;
     }
+    pushType(Any{});
     return true;
   }
 
   if (Name == "local.set") {
     if (!getLocal(Operands[1]->getStartLoc(), Inst.getOperand(0), Type))
       return popType(ErrorLoc, Type);
+    popType(ErrorLoc, Any{});
     return true;
   }
 
@@ -341,6 +344,8 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
       pushType(Type);
       return Error;
     }
+    popType(ErrorLoc, Any{});
+    pushType(Any{});
     return true;
   }
 
@@ -349,12 +354,14 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
       pushType(Type);
       return false;
     }
+    pushType(Any{});
     return true;
   }
 
   if (Name == "global.set") {
     if (!getGlobal(Operands[1]->getStartLoc(), Inst.getOperand(0), Type))
       return popType(ErrorLoc, Type);
+    popType(ErrorLoc, Any{});
     return true;
   }
 
@@ -364,16 +371,21 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
       pushType(Type);
       return Error;
     }
+    pushType(Any{});
     return true;
   }
 
   if (Name == "table.set") {
     bool Error = false;
-    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type))
-      Error |= popType(ErrorLoc, Type);
-    else
+    SmallVector<StackType, 2> PopTypes;
+    PopTypes.push_back(wasm::ValType::I32);
+    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type)) {
+      PopTypes.push_back(Type);
+    } else {
       Error = true;
-    Error |= popType(ErrorLoc, wasm::ValType::I32);
+      PopTypes.push_back(Any{});
+    }
+    Error |= popTypes(ErrorLoc, PopTypes);
     return Error;
   }
 
@@ -384,22 +396,32 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
   }
 
   if (Name == "table.grow") {
-    bool Error = popType(ErrorLoc, wasm::ValType::I32);
-    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type))
-      Error |= popType(ErrorLoc, Type);
-    else
+    bool Error = false;
+    SmallVector<StackType, 2> PopTypes;
+    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type)) {
+      PopTypes.push_back(Type);
+    } else {
       Error = true;
+      PopTypes.push_back(Any{});
+    }
+    PopTypes.push_back(wasm::ValType::I32);
+    Error |= popTypes(ErrorLoc, PopTypes);
     pushType(wasm::ValType::I32);
     return Error;
   }
 
   if (Name == "table.fill") {
-    bool Error = popType(ErrorLoc, wasm::ValType::I32);
-    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type))
-      Error |= popType(ErrorLoc, Type);
-    else
+    bool Error = false;
+    SmallVector<StackType, 2> PopTypes;
+    PopTypes.push_back(wasm::ValType::I32);
+    if (!getTable(Operands[1]->getStartLoc(), Inst.getOperand(0), Type)) {
+      PopTypes.push_back(Type);
+    } else {
       Error = true;
-    Error |= popType(ErrorLoc, wasm::ValType::I32);
+      PopTypes.push_back(Any{});
+    }
+    PopTypes.push_back(wasm::ValType::I32);
+    Error |= popTypes(ErrorLoc, PopTypes);
     return Error;
   }
 
@@ -525,7 +547,7 @@ bool WebAssemblyAsmTypeCheck::typeCheck(SMLoc ErrorLoc, const MCInst &Inst,
     if (Op.OperandType == MCOI::OPERAND_REGISTER)
       PopTypes.push_back(WebAssembly::regClassToValType(Op.RegClass));
   }
-  bool Error = checkAndPopTypes(ErrorLoc, PopTypes, false);
+  bool Error = popTypes(ErrorLoc, PopTypes);
   SmallVector<wasm::ValType, 4> PushTypes;
   // Now push all the defs onto the stack.
   for (unsigned I = 0; I < II.getNumDefs(); I++) {

llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmTypeCheck.h

@@ -40,17 +40,21 @@ class WebAssemblyAsmTypeCheck final {
   bool Unreachable = false;
   bool Is64;
 
+  // checkTypes checks 'Types' against the value stack. popTypes checks 'Types'
+  // against the value stack and also pops them.
+  //
   // If ExactMatch is true, 'Types' will be compared against not only the top of
   // the value stack but the whole remaining value stack
   // (TODO: This should be the whole remaining value stack "at the the current
   // block level", which has not been implemented yet)
   bool checkTypes(SMLoc ErrorLoc, ArrayRef<wasm::ValType> Types,
-                  bool ExactMatch);
-  bool checkTypes(SMLoc ErrorLoc, ArrayRef<StackType> Types, bool ExactMatch);
-  bool checkAndPopTypes(SMLoc ErrorLoc, ArrayRef<wasm::ValType> Types,
-                        bool ExactMatch);
-  bool checkAndPopTypes(SMLoc ErrorLoc, ArrayRef<StackType> Types,
-                        bool ExactMatch);
+                  bool ExactMatch = false);
+  bool checkTypes(SMLoc ErrorLoc, ArrayRef<StackType> Types,
+                  bool ExactMatch = false);
+  bool popTypes(SMLoc ErrorLoc, ArrayRef<wasm::ValType> Types,
+                bool ExactMatch = false);
+  bool popTypes(SMLoc ErrorLoc, ArrayRef<StackType> Types,
+                bool ExactMatch = false);
   bool popType(SMLoc ErrorLoc, StackType Type);
   bool popRefType(SMLoc ErrorLoc);
   bool popAnyType(SMLoc ErrorLoc);

llvm/test/MC/WebAssembly/type-checker-errors.s

@@ -139,31 +139,30 @@ table_set_missing_tabletype:
 
 table_set_empty_stack_while_popping_1:
   .functype table_set_empty_stack_while_popping_1 () -> ()
-# CHECK: :[[@LINE+2]]:3: error: type mismatch, expected [externref] but got []
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref] but got []
   table.set valid_table
   end_function
 
 table_set_empty_stack_while_popping_2:
   .functype table_set_empty_stack_while_popping_2 (externref) -> ()
   local.get 0
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref] but got [externref]
   table.set valid_table
   end_function
 
 table_set_type_mismatch_1:
   .functype table_set_type_mismatch_1 () -> ()
   i32.const 0
   ref.null_func
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [externref] but got [funcref]
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref] but got [i32, funcref]
   table.set valid_table
   end_function
 
 table_set_type_mismatch_2:
   .functype table_set_type_mismatch_2 () -> ()
   f32.const 1.0
   ref.null_extern
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got [f32]
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref] but got [f32, externref]
   table.set valid_table
   end_function
 
@@ -187,25 +186,22 @@ table_fill_missing_tabletype:
 
 table_fill_empty_stack_while_popping_1:
   .functype table_fill_empty_stack_while_popping_1 () -> ()
-# CHECK: :[[@LINE+3]]:3: error: type mismatch, expected [i32] but got []
-# CHECK: :[[@LINE+2]]:3: error: type mismatch, expected [externref] but got []
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got []
   table.fill valid_table
   end_function
 
 table_fill_empty_stack_while_popping_2:
   .functype table_fill_empty_stack_while_popping_2 (i32) -> ()
   local.get 0
-# CHECK: :[[@LINE+2]]:3: error: type mismatch, expected [externref] but got []
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [i32]
   table.fill valid_table
   end_function
 
 table_fill_empty_stack_while_popping_3:
   .functype table_fill_empty_stack_while_popping_3 (i32, externref) -> ()
   local.get 1
   local.get 0
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [externref, i32]
   table.fill valid_table
   end_function
 
@@ -214,7 +210,7 @@ table_fill_type_mismatch_1:
   i32.const 0
   ref.null_extern
   ref.null_func
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got [funcref]
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [i32, externref, funcref]
   table.fill valid_table
   end_function
 
@@ -223,7 +219,7 @@ table_fill_type_mismatch_2:
   i32.const 0
   ref.null_func
   i32.const 1
-# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [externref] but got [funcref]
+# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [i32, funcref, i32]
   table.fill valid_table
   end_function
 
@@ -232,7 +228,7 @@ table_fill_type_mismatch_3:
   f32.const 2.0
   ref.null_extern
   i32.const 1
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got [f32]
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [f32, externref, i32]
   table.fill valid_table
   end_function
 
@@ -241,7 +237,7 @@ table_fill_type_mismatch_4:
   i32.const 1
   ref.null_exn
   i32.const 1
-# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [externref] but got [exnref]
+# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [i32, exnref, i32]
   table.fill valid_table
   end_function
 
@@ -256,15 +252,15 @@ table_grow_non_exist_table:
 table_grow_type_mismatch_1:
   .functype table_grow_type_mismatch_1 (externref, i32) -> (i32)
   local.get 1
-# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [externref] but got []
+# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [externref, i32] but got [i32]
   table.grow valid_table
   end_function
 
 table_grow_type_mismatch_2:
   .functype table_grow_type_mismatch_2 (externref, i32) -> (i32)
   local.get 0
   local.get 0
-# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [i32] but got [externref]
+# CHECK: [[@LINE+1]]:3: error: type mismatch, expected [externref, i32] but got [externref, externref]
   table.grow valid_table
   end_function
 
@@ -883,9 +879,7 @@ multiple_errors_in_function:
 # CHECK: :[[@LINE+1]]:13: error: expected expression operand
   table.get 1
 
-# CHECK: :[[@LINE+3]]:3: error: type mismatch, expected [i32] but got []
-# CHECK: :[[@LINE+2]]:3: error: type mismatch, expected [externref] but got []
-# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got []
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32, externref, i32] but got [any]
   table.fill valid_table
 
   f32.const 0.0
@@ -905,3 +899,29 @@ call_with_multi_param_and_return:
   call take_and_return_multi
 # CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [i32] but got [i32, i64, f32, f64]
   end_function
+
+.functype callee (f32, i32) -> ()
+
+any_value_on_stack:
+  .functype any_value_on_stack () -> ()
+  # This local does not exist so it should error out, but it should put an 'any'
+  # value on the stack so 'call callee' should not error out again
+# CHECK: :[[@LINE+1]]:13: error: no local type specified for index 0
+  local.get 0
+  i32.const 0
+# CHECK-NOT: :[[@LINE+1]]:3: error: type mismatch
+  call callee
+
+  # But this time 'call callee' should error out
+  i32.const 0
+# CHECK: :[[@LINE+1]]:13: error: no local type specified for index 0
+  local.get 0
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [f32, i32] but got [i32, any]
+  call callee
+
+# CHECK: :[[@LINE+2]]:13: error: no local type specified for index 0
+# CHECK: :[[@LINE+1]]:3: error: type mismatch, expected [any] but got []
+  local.set 0
+  drop
+
+  end_function