Fix a crash in try-catch

Signed-off-by: Zoltan Herczeg [email protected]

Author: zherczeg

src/jit/Analysis.cpp

@@ -96,10 +96,13 @@ void DependencyGenContext::update(size_t dependencyStart, size_t id, size_t excl
            && maxDistance[dependencyStart / size] <= id);
 
     for (auto it : param) {
-        VariableRef ref = variableList->variables.size();
+        if (variableList != nullptr) {
+            // Construct new variables.
+            VariableRef ref = variableList->variables.size();
 
-        dependencies[dependencyStart + offset].insert(VARIABLE_SET(ref, Variable));
-        variableList->variables.push_back(VariableList::Variable(VARIABLE_SET(offset, Instruction::Offset), 0, id));
+            dependencies[dependencyStart + offset].insert(VARIABLE_SET(ref, Variable));
+            variableList->variables.push_back(VariableList::Variable(VARIABLE_SET(offset, Instruction::Offset), 0, id));
+        }
 
         offset += STACK_OFFSET(valueStackAllocatedSize(it));
     }
@@ -287,6 +290,7 @@ void JITCompiler::buildVariables(uint32_t requiredStackSize)
     size_t nextId = 0;
     size_t nextTryBlock = m_tryBlockStart;
 
+    // Create variables for each result or external values.
     for (InstructionListItem* item = m_first; item != nullptr; item = item->next()) {
         item->m_id = ++nextId;
 
@@ -322,6 +326,7 @@ void JITCompiler::buildVariables(uint32_t requiredStackSize)
 
     DependencyGenContext dependencyCtx(dependencySize, requiredStackSize);
     bool updateDeps = true;
+    std::vector<size_t> activeTryBlocks;
 
     m_variableList = new VariableList(variableCount, requiredStackSize);
     nextTryBlock = m_tryBlockStart;
@@ -365,11 +370,16 @@ void JITCompiler::buildVariables(uint32_t requiredStackSize)
                         }
                     }
 
+                    activeTryBlocks.push_back(nextTryBlock);
                     nextTryBlock++;
                 } while (nextTryBlock < tryBlocks().size()
                          && tryBlocks()[nextTryBlock].start == label);
             }
 
+            if (label->info() & Label::kHasCatchInfo) {
+                activeTryBlocks.pop_back();
+            }
+
             for (size_t i = 0; i < requiredStackSize; ++i) {
                 dependencyCtx.currentDependencies[i] = VARIABLE_SET_PTR(label);
                 dependencyCtx.currentOptions[i] = 0;
@@ -424,7 +434,28 @@ void JITCompiler::buildVariables(uint32_t requiredStackSize)
             continue;
         }
 
-        if (instr->opcode() == ByteCode::ThrowOpcode || instr->opcode() == ByteCode::UnreachableOpcode) {
+        if (activeTryBlocks.size() > 0 && (instr->group() == Instruction::Call || instr->opcode() == ByteCode::ThrowOpcode)) {
+            // Every call or throw may jump to any active catch block. Future
+            // optimizations could reduce these (e.g. a throw can be converted
+            // to a jump if its target catch block is in the same function).
+            for (auto blockIt : activeTryBlocks) {
+                for (auto it : tryBlocks()[blockIt].catchBlocks) {
+                    if (it.tagIndex == std::numeric_limits<uint32_t>::max()) {
+                        dependencyCtx.update(it.u.handler->m_dependencyStart, instr->id());
+                    } else {
+                        TagType* tagType = module()->tagType(it.tagIndex);
+                        const ValueTypeVector& param = module()->functionType(tagType->sigIndex())->param();
+                        Label* catchLabel = it.u.handler;
+
+                        dependencyCtx.update(catchLabel->m_dependencyStart, catchLabel->id(),
+                                             STACK_OFFSET(it.stackSizeToBe), param, nullptr);
+                    }
+                }
+            }
+        }
+
+        if (instr->opcode() == ByteCode::ThrowOpcode || instr->opcode() == ByteCode::UnreachableOpcode
+            || instr->opcode() == ByteCode::EndOpcode) {
             updateDeps = false;
             continue;
         }
@@ -495,6 +526,7 @@ void JITCompiler::buildVariables(uint32_t requiredStackSize)
     }
 
     ASSERT(variableCount == m_variableList->variables.size());
+    ASSERT(activeTryBlocks.size() == 0);
 
     // Phase 2: the indirect instruction
     // references are computed for labels.

src/jit/RegisterAlloc.cpp

@@ -298,14 +298,16 @@ uint8_t RegisterSet::allocateRegisterPair(VariableList::Variable* variable, uint
     size_t freeReg = VariableList::kUnusedReg;
     uint16_t constraints = variable != nullptr ? variable->info : 0;
     size_t size = m_registers.size();
-    size_t i = 0;
+    size_t minIndex = 0;
 
     if (constraints & VariableList::kIsCallback) {
-        i = m_savedStartIndex;
+        minIndex = m_savedStartIndex;
     } else if ((constraints & VariableList::kDestroysR0R1) && (m_regStatus & kIsInteger)) {
-        i = 2;
+        minIndex = 2;
     }
 
+    size_t i = minIndex;
+
     while (i < size) {
         if (m_registers[i].rangeEnd == kUnassignedReg) {
             if (freeReg != VariableList::kUnusedReg) {
@@ -317,7 +319,8 @@ uint8_t RegisterSet::allocateRegisterPair(VariableList::Variable* variable, uint
             VariableList::Variable* targetVariable = m_registers[i].variable;
 
             if (targetVariable->reg1 != targetVariable->reg2) {
-                if (targetVariable->rangeEnd > maxRangeEndPair) {
+                if (targetVariable->reg1 >= minIndex && targetVariable->reg2 >= minIndex
+                    && targetVariable->rangeEnd > maxRangeEndPair) {
                     maxRangeEndPair = targetVariable->rangeEnd;
                     maxRangeIndexPair = i;
                 }

test/jit/trycatch-dep.wast

@@ -0,0 +1,103 @@
+(module
+  (memory 1)
+
+  (tag $except0 (param i32 i64))
+  (tag $except1 (param f32 f64))
+  (tag $except3)
+
+  (func $throw1 (param i64)
+     i32.const 1234
+     local.get 0
+     throw $except0
+  )
+
+  (func $throw2 (param i64)
+     f32.const 2345.0
+     local.get 0
+     f64.convert_i64_s
+     throw $except1
+  )
+
+  (func $throw3 (param i64)
+     throw $except3
+  )
+
+  (func (export "try1") (param i64) (result i64 i32) (local $l1 i64) (local $l2 i32)
+    i32.const 123456
+    local.set $l2
+    (try
+      (do
+        (try
+          (do
+            local.get 0
+            local.set $l1
+
+            local.get $l1
+            i32.wrap_i64
+            i32.const 100
+            i32.add
+            local.set $l2
+
+            i64.const 1000
+            local.get $l1
+            i64.lt_s
+            if
+              local.get $l1
+              call $throw1
+            end
+
+            local.get $l1
+            i64.const 500
+            i64.gt_s
+            if
+              local.get $l1
+              call $throw2
+            end
+
+            local.get $l1
+            i64.const 250
+            i64.gt_s
+            if
+              local.get $l1
+              call $throw3
+            end
+
+            local.get $l1
+            i64.const 17
+            i64.sub
+            i32.const -678
+            return
+          )
+          (catch $except0
+            local.set $l1
+            i64.extend_i32_s
+            local.get $l1
+            i64.add
+            local.set $l1
+          )
+        )
+      )
+      (catch $except1
+        i64.trunc_sat_f64_s
+        local.set $l1
+
+        i64.trunc_sat_f32_s
+        local.get $l1
+        i64.add
+        local.set $l1
+      )
+      (catch_all
+        i64.const 888
+        local.set $l1
+      )
+    )
+
+    local.get $l1
+    local.get $l2
+  )
+)
+
+(assert_return (invoke "try1" (i64.const 99)) (i64.const 82) (i32.const -678))
+(assert_return (invoke "try1" (i64.const 2000)) (i64.const 3234) (i32.const 2100))
+(assert_return (invoke "try1" (i64.const 600)) (i64.const 2945) (i32.const 700))
+(assert_return (invoke "try1" (i64.const 300)) (i64.const 888) (i32.const 400))