From 7418f29dc7d7165fda2c6716d71d223bdc703084 Mon Sep 17 00:00:00 2001
From: Andy Ayers <andya@microsoft.com>
Date: Thu, 11 Dec 2025 17:17:58 -0800
Subject: [PATCH] [Wasm RyuJit] Fixes for some issues in codegen bringup tests

The strategy for marking blocks that need labels was wrong. We need to
mark block ends when we encounter block starts. To do this efficiently
we need to map from interval end index to block, so expose the map we
built during interval building for use in codegen.

We likely don't need Just My Code debug support for Wasm, so ignore any
request from the runtime to insert the checks.

Wasm structured control flow doesn't allow us to keep blocks in increasing
IL offset order (in general). So disable some of the scope tracking mechanisms
that expect to see this.

Fix another instance where we assumed a 32 bit target would decompose longs.
---
 src/coreclr/jit/codegenwasm.cpp | 25 ++++++++++++++++---------
 src/coreclr/jit/compiler.h      |  1 +
 src/coreclr/jit/fgwasm.cpp      |  4 ++++
 src/coreclr/jit/flowgraph.cpp   |  3 +++
 src/coreclr/jit/lower.cpp       |  4 ++--
 src/coreclr/jit/scopeinfo.cpp   |  9 +++++++++
 6 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/src/coreclr/jit/codegenwasm.cpp b/src/coreclr/jit/codegenwasm.cpp
index b119fac5a4f9e1..7359ac78bb006f 100644
--- a/src/coreclr/jit/codegenwasm.cpp
+++ b/src/coreclr/jit/codegenwasm.cpp
@@ -155,12 +155,6 @@ void CodeGen::genEmitStartBlock(BasicBlock* block)
     {
         instGen(INS_end);
         WasmInterval* interval = wasmControlFlowStack->Pop();
-
-        if (!interval->IsLoop() && !block->HasFlag(BBF_HAS_LABEL))
-        {
-            block->SetFlags(BBF_HAS_LABEL);
-            genDefineTempLabel(block);
-        }
     }
 
     // Push control flow for intervals that start here or earlier, and emit
@@ -185,10 +179,23 @@ void CodeGen::genEmitStartBlock(BasicBlock* block)
             wasmCursor++;
             wasmControlFlowStack->Push(interval);
 
-            if (interval->IsLoop() && !block->HasFlag(BBF_HAS_LABEL))
+            if (interval->IsLoop())
             {
-                block->SetFlags(BBF_HAS_LABEL);
-                genDefineTempLabel(block);
+                if (!block->HasFlag(BBF_HAS_LABEL))
+                {
+                    block->SetFlags(BBF_HAS_LABEL);
+                    genDefineTempLabel(block);
+                }
+            }
+            else
+            {
+                BasicBlock* const endBlock = compiler->fgIndexToBlockMap[interval->End()];
+
+                if (!endBlock->HasFlag(BBF_HAS_LABEL))
+                {
+                    endBlock->SetFlags(BBF_HAS_LABEL);
+                    genDefineTempLabel(endBlock);
+                }
             }
 
             if (wasmCursor >= compiler->fgWasmIntervals->size())
diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
index abd9666e5114bf..10dce87e452942 100644
--- a/src/coreclr/jit/compiler.h
+++ b/src/coreclr/jit/compiler.h
@@ -5242,6 +5242,7 @@ class Compiler
 
 #ifdef TARGET_WASM
     jitstd::vector<WasmInterval*>* fgWasmIntervals = nullptr;
+    BasicBlock** fgIndexToBlockMap = nullptr;
 #endif
 
     FlowGraphDfsTree* m_dfsTree = nullptr;
diff --git a/src/coreclr/jit/fgwasm.cpp b/src/coreclr/jit/fgwasm.cpp
index a00fdb71531ead..d55db54b0065d4 100644
--- a/src/coreclr/jit/fgwasm.cpp
+++ b/src/coreclr/jit/fgwasm.cpp
@@ -1407,6 +1407,10 @@ PhaseStatus Compiler::fgWasmControlFlow()
         }
     }
 
+    // Publish the index to block map for use during codegen.
+    //
+    fgIndexToBlockMap = initialLayout;
+
     JITDUMPEXEC(fgDumpWasmControlFlow());
     JITDUMPEXEC(fgDumpWasmControlFlowDot());
 
diff --git a/src/coreclr/jit/flowgraph.cpp b/src/coreclr/jit/flowgraph.cpp
index f2f80ee0d67d62..43a0305c9b48c7 100644
--- a/src/coreclr/jit/flowgraph.cpp
+++ b/src/coreclr/jit/flowgraph.cpp
@@ -2492,10 +2492,13 @@ PhaseStatus Compiler::fgAddInternal()
 
     CORINFO_JUST_MY_CODE_HANDLE* pDbgHandle = nullptr;
     CORINFO_JUST_MY_CODE_HANDLE  dbgHandle  = nullptr;
+
+#if !defined(TARGET_WASM)
     if (opts.compDbgCode && !opts.jitFlags->IsSet(JitFlags::JIT_FLAG_IL_STUB))
     {
         dbgHandle = info.compCompHnd->getJustMyCodeHandle(info.compMethodHnd, &pDbgHandle);
     }
+#endif
 
     noway_assert(!dbgHandle || !pDbgHandle);
 
diff --git a/src/coreclr/jit/lower.cpp b/src/coreclr/jit/lower.cpp
index 7ab77c2b84a5ed..118d7b75b320e1 100644
--- a/src/coreclr/jit/lower.cpp
+++ b/src/coreclr/jit/lower.cpp
@@ -4526,12 +4526,12 @@ GenTree* Lowering::OptimizeConstCompare(GenTree* cmp)
 //
 GenTree* Lowering::LowerCompare(GenTree* cmp)
 {
-#ifndef TARGET_64BIT
+#if LOWER_DECOMPOSE_LONGS
     if (cmp->gtGetOp1()->TypeIs(TYP_LONG))
     {
         return DecomposeLongCompare(cmp);
     }
-#endif
+#endif // LOWER_DECOMPOSE_LONGS
 
     if (cmp->gtGetOp2()->IsIntegralConst() && !comp->opts.MinOpts())
     {
diff --git a/src/coreclr/jit/scopeinfo.cpp b/src/coreclr/jit/scopeinfo.cpp
index df9b0083798d1a..6ded2a0d587d9d 100644
--- a/src/coreclr/jit/scopeinfo.cpp
+++ b/src/coreclr/jit/scopeinfo.cpp
@@ -1541,6 +1541,15 @@ void CodeGen::siBeginBlock(BasicBlock* block)
 //
 void CodeGen::siOpenScopesForNonTrackedVars(const BasicBlock* block, unsigned int lastBlockILEndOffset)
 {
+#if defined(TARGET_WASM)
+    // TODO-WASM: Wasm structured control flow
+    // requirements are incompatible with debug codegen's
+    // desire to keep blocks in increasing IL offset
+    // order. Figure out the proper scope manipulations.
+    //
+    return;
+#endif // defined(TARGET_WASM)
+
     unsigned int beginOffs = block->bbCodeOffs;
 
     // There aren't any tracked locals.