[C API] Add getters and build function for CallBr (#91154)

This adds LLVMBuildCallBr to create CallBr instructions, and getters for
the CallBr-specific data. The remainder of its data, e.g.
arguments/function, can be accessed using existing getters.

Author: Benjins

llvm/docs/ReleaseNotes.rst

@@ -168,6 +168,13 @@ Changes to the C API
 
 * Added ``LLVMCreateConstantRangeAttribute`` function for creating ConstantRange Attributes.
 
+* Added the following functions for creating and accessing data for CallBr instructions:
+
+  * ``LLVMBuildCallBr``
+  * ``LLVMGetCallBrDefaultDest``
+  * ``LLVMGetCallBrNumIndirectDests``
+  * ``LLVMGetCallBrIndirectDest``
+
 Changes to the CodeGen infrastructure
 -------------------------------------
 

llvm/include/llvm-c/Core.h

@@ -3737,6 +3737,28 @@ void LLVMSetNormalDest(LLVMValueRef InvokeInst, LLVMBasicBlockRef B);
  */
 void LLVMSetUnwindDest(LLVMValueRef InvokeInst, LLVMBasicBlockRef B);
 
+/**
+ * Get the default destination of a CallBr instruction.
+ *
+ * @see llvm::CallBrInst::getDefaultDest()
+ */
+LLVMBasicBlockRef LLVMGetCallBrDefaultDest(LLVMValueRef CallBr);
+
+/**
+ * Get the number of indirect destinations of a CallBr instruction.
+ *
+ * @see llvm::CallBrInst::getNumIndirectDests()
+
+ */
+unsigned LLVMGetCallBrNumIndirectDests(LLVMValueRef CallBr);
+
+/**
+ * Get the indirect destination of a CallBr instruction at the given index.
+ *
+ * @see llvm::CallBrInst::getIndirectDest()
+ */
+LLVMBasicBlockRef LLVMGetCallBrIndirectDest(LLVMValueRef CallBr, unsigned Idx);
+
 /**
  * @}
  */
@@ -4023,6 +4045,12 @@ LLVMValueRef LLVMBuildSwitch(LLVMBuilderRef, LLVMValueRef V,
                              LLVMBasicBlockRef Else, unsigned NumCases);
 LLVMValueRef LLVMBuildIndirectBr(LLVMBuilderRef B, LLVMValueRef Addr,
                                  unsigned NumDests);
+LLVMValueRef LLVMBuildCallBr(LLVMBuilderRef B, LLVMTypeRef Ty, LLVMValueRef Fn,
+                             LLVMBasicBlockRef DefaultDest,
+                             LLVMBasicBlockRef *IndirectDests,
+                             unsigned NumIndirectDests, LLVMValueRef *Args,
+                             unsigned NumArgs, LLVMOperandBundleRef *Bundles,
+                             unsigned NumBundles, const char *Name);
 LLVMValueRef LLVMBuildInvoke2(LLVMBuilderRef, LLVMTypeRef Ty, LLVMValueRef Fn,
                               LLVMValueRef *Args, unsigned NumArgs,
                               LLVMBasicBlockRef Then, LLVMBasicBlockRef Catch,

llvm/lib/IR/Core.cpp

@@ -47,6 +47,10 @@ using namespace llvm;
 
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(OperandBundleDef, LLVMOperandBundleRef)
 
+inline BasicBlock **unwrap(LLVMBasicBlockRef *BBs) {
+  return reinterpret_cast<BasicBlock **>(BBs);
+}
+
 #define DEBUG_TYPE "ir"
 
 void llvm::initializeCore(PassRegistry &Registry) {
@@ -3031,6 +3035,18 @@ void LLVMSetUnwindDest(LLVMValueRef Invoke, LLVMBasicBlockRef B) {
   unwrap<InvokeInst>(Invoke)->setUnwindDest(unwrap(B));
 }
 
+LLVMBasicBlockRef LLVMGetCallBrDefaultDest(LLVMValueRef CallBr) {
+  return wrap(unwrap<CallBrInst>(CallBr)->getDefaultDest());
+}
+
+unsigned LLVMGetCallBrNumIndirectDests(LLVMValueRef CallBr) {
+  return unwrap<CallBrInst>(CallBr)->getNumIndirectDests();
+}
+
+LLVMBasicBlockRef LLVMGetCallBrIndirectDest(LLVMValueRef CallBr, unsigned Idx) {
+  return wrap(unwrap<CallBrInst>(CallBr)->getIndirectDest(Idx));
+}
+
 /*--.. Operations on terminators ...........................................--*/
 
 unsigned LLVMGetNumSuccessors(LLVMValueRef Term) {
@@ -3258,6 +3274,25 @@ LLVMValueRef LLVMBuildIndirectBr(LLVMBuilderRef B, LLVMValueRef Addr,
   return wrap(unwrap(B)->CreateIndirectBr(unwrap(Addr), NumDests));
 }
 
+LLVMValueRef LLVMBuildCallBr(LLVMBuilderRef B, LLVMTypeRef Ty, LLVMValueRef Fn,
+                             LLVMBasicBlockRef DefaultDest,
+                             LLVMBasicBlockRef *IndirectDests,
+                             unsigned NumIndirectDests, LLVMValueRef *Args,
+                             unsigned NumArgs, LLVMOperandBundleRef *Bundles,
+                             unsigned NumBundles, const char *Name) {
+
+  SmallVector<OperandBundleDef, 8> OBs;
+  for (auto *Bundle : ArrayRef(Bundles, NumBundles)) {
+    OperandBundleDef *OB = unwrap(Bundle);
+    OBs.push_back(*OB);
+  }
+
+  return wrap(unwrap(B)->CreateCallBr(
+      unwrap<FunctionType>(Ty), unwrap(Fn), unwrap(DefaultDest),
+      ArrayRef(unwrap(IndirectDests), NumIndirectDests),
+      ArrayRef<Value *>(unwrap(Args), NumArgs), OBs, Name));
+}
+
 LLVMValueRef LLVMBuildInvoke2(LLVMBuilderRef B, LLVMTypeRef Ty, LLVMValueRef Fn,
                               LLVMValueRef *Args, unsigned NumArgs,
                               LLVMBasicBlockRef Then, LLVMBasicBlockRef Catch,

llvm/test/Bindings/llvm-c/echo.ll

@@ -348,6 +348,32 @@ define void @test_func_prologue_data_01() prologue %func_prolog_struct <{ i8 235
   ret void
 }
 
+
+define void @test_call_br_01(i32 %input) {
+entry:
+  callbr void asm "nop", "r,!i"(i32 %input) to label %bb_01 [label %bb_02]
+
+bb_01:
+  ret void
+bb_02:
+  ret void
+}
+
+define void @test_call_br_02(i32 %input0, i32 %input1) {
+entry:
+  ; Multiple indirect destinations, operand bundles, and arguments
+  callbr void asm "nop", "r,r,!i,!i"(i32 %input0, i32 %input1)
+    ["op0"(i32 %input1), "op1"(label %bb_02)]
+    to label %bb_01 [label %bb_03, label %bb_02]
+
+bb_01:
+  ret void
+bb_02:
+  ret void
+bb_03:
+  ret void
+}
+
 !llvm.dbg.cu = !{!0, !2}
 !llvm.module.flags = !{!3}
 

llvm/tools/llvm-c-test/echo.cpp

@@ -570,6 +570,46 @@ struct FunCloner {
           LLVMDisposeOperandBundle(Bundle);
         break;
       }
+      case LLVMCallBr: {
+        LLVMTypeRef FnTy = CloneType(LLVMGetCalledFunctionType(Src));
+        LLVMValueRef Fn = CloneValue(LLVMGetCalledValue(Src));
+
+        LLVMBasicBlockRef DefaultDest =
+            DeclareBB(LLVMGetCallBrDefaultDest(Src));
+
+        // Clone indirect destinations
+        SmallVector<LLVMBasicBlockRef, 8> IndirectDests;
+        unsigned IndirectDestCount = LLVMGetCallBrNumIndirectDests(Src);
+        for (unsigned i = 0; i < IndirectDestCount; ++i)
+          IndirectDests.push_back(DeclareBB(LLVMGetCallBrIndirectDest(Src, i)));
+
+        // Clone input arguments
+        SmallVector<LLVMValueRef, 8> Args;
+        unsigned ArgCount = LLVMGetNumArgOperands(Src);
+        for (unsigned i = 0; i < ArgCount; ++i)
+          Args.push_back(CloneValue(LLVMGetOperand(Src, i)));
+
+        // Clone operand bundles
+        SmallVector<LLVMOperandBundleRef, 8> Bundles;
+        unsigned BundleCount = LLVMGetNumOperandBundles(Src);
+        for (unsigned i = 0; i < BundleCount; ++i) {
+          auto Bundle = LLVMGetOperandBundleAtIndex(Src, i);
+          Bundles.push_back(CloneOB(Bundle));
+          LLVMDisposeOperandBundle(Bundle);
+        }
+
+        Dst = LLVMBuildCallBr(Builder, FnTy, Fn, DefaultDest,
+                              IndirectDests.data(), IndirectDests.size(),
+                              Args.data(), Args.size(), Bundles.data(),
+                              Bundles.size(), Name);
+
+        CloneAttrs(Src, Dst);
+
+        for (auto Bundle : Bundles)
+          LLVMDisposeOperandBundle(Bundle);
+
+        break;
+      }
       case LLVMUnreachable:
         Dst = LLVMBuildUnreachable(Builder);
         break;