From cdc98c92566eac0f4694e537d0aca90bb243bd4f Mon Sep 17 00:00:00 2001
From: Natalia Gavrilenko <natgavrilenko@gmail.com>
Date: Tue, 1 Jul 2025 12:00:35 +0200
Subject: [PATCH] Warning if cbar synchronizes across workgroups

Print a warning if control barriers with the same instance id are
used across different workgroups. Update existing tests with such
barriers to use acquire-release memory accesses instead.

Signed-off-by: Natalia Gavrilenko <natalia.gavrilenko@huawei.com>
---
 alloy/litmus.cpp            | 14 +++++++++++---
 alloy/tests/scopeaccum.test |  4 ++--
 alloy/tests/test6.test      |  8 ++++----
 alloy/tests/test7.test      |  8 ++++----
 4 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/alloy/litmus.cpp b/alloy/litmus.cpp
index 02ae5dc..f4637fc 100644
--- a/alloy/litmus.cpp
+++ b/alloy/litmus.cpp
@@ -116,11 +116,12 @@ using namespace std;
 // instances.
 class LoadStore {
 public:
-    LoadStore() : var(), value(-1), value2(-1), cbarInstance(-1) {}
+    LoadStore() : var(), value(-1), value2(-1), cbarInstance(-1), workgroup(-1) {}
     string var;
     int value;
     int value2;
     int cbarInstance;
+    int workgroup;
 };
 
 // Track what instruction fields are set for each instruction.
@@ -141,14 +142,14 @@ class InstructionState {
     int getReadValue(int instnum) const
     {
         if (!isRead(instnum)) {
-            printf("WARNING: calling getReadValue on a non-read");
+            printf("WARNING: calling getReadValue on a non-read\n");
         }
         return loadStore[instnum].value;
     }
     int getWriteValue(int instnum) const
     {
         if (!isWrite(instnum)) {
-            printf("WARNING: calling getWriteValue on a non-write");
+            printf("WARNING: calling getWriteValue on a non-write\n");
         }
         return (isRead(instnum) && isWrite(instnum)) ? loadStore[instnum].value2 : loadStore[instnum].value;
     }
@@ -340,6 +341,7 @@ int main(int argc, char *argv[])
 
     stringstream o;
 
+    int workgroupnum = 0;
     int threadnum = 0;
     int numEvents = 0;
     int bitwidth = 0;
@@ -390,6 +392,7 @@ int main(int argc, char *argv[])
                 o << "    no ("; sequenceInSuffix(o, 0, instnum+1, true, ") & X.swg");
                 firstInstInWG = instnum+1;
             }
+            workgroupnum++;
             continue;
         }
 
@@ -452,6 +455,7 @@ int main(int argc, char *argv[])
                 line = line.substr(firstspace);
                 line = line.substr(line.find_first_not_of(" "));
                 instState.loadStore[instnum].cbarInstance = atoi(line.c_str());
+                instState.loadStore[instnum].workgroup = workgroupnum;
             } else {
                 line = line.substr(firstspace);
                 line = line.substr(line.find_first_not_of(" ="));
@@ -602,12 +606,16 @@ int main(int argc, char *argv[])
     set<int> cbarInsts;
     for (int j = 0; j <= instnum; ++j) {
         int v = instState.loadStore[j].cbarInstance;
+        int w = instState.loadStore[j].workgroup;
         if (v != -1 && cbarInsts.find(v) == cbarInsts.end()) {
             cbarInsts.insert(v);
             o << "    ";
             bool first = true;
             for (int i = j+1; i <= instnum; ++i) {
                 if (instState.loadStore[i].cbarInstance == v) {
+                    if (instState.loadStore[i].workgroup != w) {
+                        printf("WARNING: matching control barriers in different workgroups\n");
+                    }
                     if (!first) {
                         o << "+";
                     }
diff --git a/alloy/tests/scopeaccum.test b/alloy/tests/scopeaccum.test
index 171c060..f09f63e 100644
--- a/alloy/tests/scopeaccum.test
+++ b/alloy/tests/scopeaccum.test
@@ -10,11 +10,11 @@ cbar.scopewg.semsc0.rel.acq 1
 NEWSG
 NEWTHREAD
 cbar.scopewg.semsc0.rel.acq 1
-cbar.scopedev.semsc0.rel.acq 2
+st.atom.rel.scopedev.sc0.semsc0 y = 1
 NEWWG
 NEWSG
 NEWTHREAD
-cbar.scopedev.semsc0.rel.acq 2
+ld.atom.acq.scopedev.sc0.semsc0 y = 1
 ld.vis.scopedev.sc0 x
 SATISFIABLE consistent[X] && #dr=0
 NOSOLUTION consistent[X] && #dr>0
diff --git a/alloy/tests/test6.test b/alloy/tests/test6.test
index c68b4f7..20f9a99 100644
--- a/alloy/tests/test6.test
+++ b/alloy/tests/test6.test
@@ -11,15 +11,15 @@ cbar.acq.rel.scopewg.semsc0 0
 NEWSG
 NEWTHREAD
 cbar.acq.rel.scopewg.semsc0 0
-cbar.acq.rel.scopedev.semsc0 1
+st.atom.rel.scopedev.sc0.semsc0 y = 1
 NEWWG
 NEWSG
 NEWTHREAD
-cbar.acq.rel.scopedev.semsc0 1
-cbar.acq.rel.scopewg.semsc0 2
+ld.atom.acq.scopedev.sc0.semsc0 y = 1
+cbar.acq.rel.scopewg.semsc0 1
 NEWSG
 NEWTHREAD
-cbar.acq.rel.scopewg.semsc0 2
+cbar.acq.rel.scopewg.semsc0 1
 ld.vis.scopedev.sc0 a
 SATISFIABLE consistent[X] && #dr=0
 NOSOLUTION consistent[X] && #dr>0
diff --git a/alloy/tests/test7.test b/alloy/tests/test7.test
index f50ab81..27c7779 100644
--- a/alloy/tests/test7.test
+++ b/alloy/tests/test7.test
@@ -11,15 +11,15 @@ cbar.acq.rel.scopewg.semsc0 0
 NEWSG
 NEWTHREAD
 cbar.acq.rel.scopewg.semsc0 0
-cbar.acq.rel.scopedev.semsc1 1
+st.atom.rel.scopedev.sc0.semsc1 y = 1
 NEWWG
 NEWSG
 NEWTHREAD
-cbar.acq.rel.scopedev.semsc1 1
-cbar.acq.rel.scopewg.semsc0 2
+ld.atom.acq.scopedev.sc0.semsc1 y = 1
+cbar.acq.rel.scopewg.semsc0 1
 NEWSG
 NEWTHREAD
-cbar.acq.rel.scopewg.semsc0 2
+cbar.acq.rel.scopewg.semsc0 1
 ld.vis.scopedev.sc0 a
 NOSOLUTION consistent[X] && #dr=0
 SATISFIABLE consistent[X] && #dr>0