[CIR] Add the ability to detect if SwitchOp covers all the cases

[badumbatish]

No description provided.

[llvmbot]

@llvm/pr-subscribers-clangir

Author: Jasmine Tang (badumbatish)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/171246.diff

3 Files Affected:

• (modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+7-1)
• (modified) clang/lib/CIR/CodeGen/CIRGenStmt.cpp (+2)
• (modified) clang/test/CIR/IR/switch.cir (+30)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 9bd24cf0bcf27..d6099388886d7 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -1047,6 +1047,11 @@ def CIR_SwitchOp : CIR_Op<"switch", [
     conditionally executing multiple regions of code. The operand to an switch
     is an integral condition value.
 
+    Besides accepting an int type of condition and regions of cir code, it also accepts 
+    a boolean allEnumCasesCovered indicating if all cases of an enum is covered. Note that 
+    having a default CaseOp inside the switch doesn't imply allEnumCasesCovered, the OG AST switch
+    needs to have each case spelled out.
+
     The set of `cir.case` operations and their enclosing `cir.switch`
     represent the semantics of a C/C++ switch statement. Users can use
     `collectCases(llvm::SmallVector<CaseOp> &cases)` to collect the `cir.case`
@@ -1173,7 +1178,8 @@ def CIR_SwitchOp : CIR_Op<"switch", [
     ```
   }];
 
-  let arguments = (ins CIR_IntType:$condition);
+  let arguments = (ins CIR_IntType:$condition,
+                       DefaultValuedAttr<BoolAttr, "false">:$allEnumCasesCovered);
 
   let regions = (region AnyRegion:$body);
 
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index da7ab0691cb63..0ff19abaffc08 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -1105,6 +1105,8 @@ mlir::LogicalResult CIRGenFunction::emitSwitchStmt(const clang::SwitchStmt &s) {
     terminateBody(builder, caseOp.getCaseRegion(), caseOp.getLoc());
   terminateBody(builder, swop.getBody(), swop.getLoc());
 
+  swop.setAllEnumCasesCovered(s.isAllEnumCasesCovered());
+
   return res;
 }
 
diff --git a/clang/test/CIR/IR/switch.cir b/clang/test/CIR/IR/switch.cir
index 87d45bf1f5219..78c0273b8c97e 100644
--- a/clang/test/CIR/IR/switch.cir
+++ b/clang/test/CIR/IR/switch.cir
@@ -36,3 +36,33 @@ cir.func @s0() {
 // CHECK-NEXT: }
 // CHECK-NEXT: cir.yield
 // CHECK-NEXT: }
+
+
+// Pretends that this is lowered from a C file and was tagged with allEnumCasesCovered = true
+cir.func @s1(%1 : !s32i) {
+  cir.switch (%1 : !s32i) {
+    cir.case (default, []) {
+      cir.return
+    }
+    cir.case (equal, [#cir.int<1> : !s32i]) {
+      cir.yield
+    }
+    cir.case (equal, [#cir.int<2> : !s32i]) {
+      cir.yield
+    }
+    cir.yield
+  } { allEnumCasesCovered = true}
+  cir.return
+} 
+// CHECK: cir.switch (%arg0 : !s32i) {
+// CHECK-NEXT: cir.case(default, []) {
+// CHECK-NEXT:   cir.return
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.case(equal, [#cir.int<1> : !s32i]) {
+// CHECK-NEXT:   cir.yield
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.case(equal, [#cir.int<2> : !s32i]) {
+// CHECK-NEXT:   cir.yield
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.yield
+// CHECK-NEXT: } {allEnumCasesCovered = true}

[llvmbot]

@llvm/pr-subscribers-clang

Author: Jasmine Tang (badumbatish)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/171246.diff

3 Files Affected:

• (modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+7-1)
• (modified) clang/lib/CIR/CodeGen/CIRGenStmt.cpp (+2)
• (modified) clang/test/CIR/IR/switch.cir (+30)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 9bd24cf0bcf27..d6099388886d7 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -1047,6 +1047,11 @@ def CIR_SwitchOp : CIR_Op<"switch", [
     conditionally executing multiple regions of code. The operand to an switch
     is an integral condition value.
 
+    Besides accepting an int type of condition and regions of cir code, it also accepts 
+    a boolean allEnumCasesCovered indicating if all cases of an enum is covered. Note that 
+    having a default CaseOp inside the switch doesn't imply allEnumCasesCovered, the OG AST switch
+    needs to have each case spelled out.
+
     The set of `cir.case` operations and their enclosing `cir.switch`
     represent the semantics of a C/C++ switch statement. Users can use
     `collectCases(llvm::SmallVector<CaseOp> &cases)` to collect the `cir.case`
@@ -1173,7 +1178,8 @@ def CIR_SwitchOp : CIR_Op<"switch", [
     ```
   }];
 
-  let arguments = (ins CIR_IntType:$condition);
+  let arguments = (ins CIR_IntType:$condition,
+                       DefaultValuedAttr<BoolAttr, "false">:$allEnumCasesCovered);
 
   let regions = (region AnyRegion:$body);
 
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index da7ab0691cb63..0ff19abaffc08 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -1105,6 +1105,8 @@ mlir::LogicalResult CIRGenFunction::emitSwitchStmt(const clang::SwitchStmt &s) {
     terminateBody(builder, caseOp.getCaseRegion(), caseOp.getLoc());
   terminateBody(builder, swop.getBody(), swop.getLoc());
 
+  swop.setAllEnumCasesCovered(s.isAllEnumCasesCovered());
+
   return res;
 }
 
diff --git a/clang/test/CIR/IR/switch.cir b/clang/test/CIR/IR/switch.cir
index 87d45bf1f5219..78c0273b8c97e 100644
--- a/clang/test/CIR/IR/switch.cir
+++ b/clang/test/CIR/IR/switch.cir
@@ -36,3 +36,33 @@ cir.func @s0() {
 // CHECK-NEXT: }
 // CHECK-NEXT: cir.yield
 // CHECK-NEXT: }
+
+
+// Pretends that this is lowered from a C file and was tagged with allEnumCasesCovered = true
+cir.func @s1(%1 : !s32i) {
+  cir.switch (%1 : !s32i) {
+    cir.case (default, []) {
+      cir.return
+    }
+    cir.case (equal, [#cir.int<1> : !s32i]) {
+      cir.yield
+    }
+    cir.case (equal, [#cir.int<2> : !s32i]) {
+      cir.yield
+    }
+    cir.yield
+  } { allEnumCasesCovered = true}
+  cir.return
+} 
+// CHECK: cir.switch (%arg0 : !s32i) {
+// CHECK-NEXT: cir.case(default, []) {
+// CHECK-NEXT:   cir.return
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.case(equal, [#cir.int<1> : !s32i]) {
+// CHECK-NEXT:   cir.yield
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.case(equal, [#cir.int<2> : !s32i]) {
+// CHECK-NEXT:   cir.yield
+// CHECK-NEXT: }
+// CHECK-NEXT: cir.yield
+// CHECK-NEXT: } {allEnumCasesCovered = true}

[andykaylor]

This looks good. It could also be useful to know that the switch condition variable is an enum, for cases where it's not fully covered, but that could be a separate PR.