Only flush the part of the trampoline buffer containing instructions

Author: rofirrim

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -7521,11 +7521,12 @@ SDValue RISCVTargetLowering::lowerINIT_TRAMPOLINE(SDValue Op,
 
   SDValue StoreToken = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains);
 
-  // Compute end of trampoline.
-  SDValue EndOfTrmp = DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
-                                  DAG.getConstant(32, dl, MVT::i64));
+  // Compute end of instructions of trampoline.
+  SDValue EndOfTrmp =
+      DAG.getNode(ISD::ADD, dl, MVT::i64, Trmp,
+                  DAG.getConstant(StaticChainOffset, dl, MVT::i64));
 
-  // Call clear cache on the trampoline buffer.
+  // Call clear cache on the trampoline instructions.
   SDValue Chain = DAG.getNode(ISD::CLEAR_CACHE, dl, MVT::Other, StoreToken,
                               Trmp, EndOfTrmp);
 

llvm/test/CodeGen/RISCV/rv64-trampoline.ll

@@ -28,7 +28,7 @@ define i64 @test0(i64 %n, ptr %p) nounwind {
 ; RV64-NEXT:    slli a0, a0, 32
 ; RV64-NEXT:    addi a0, a0, 919
 ; RV64-NEXT:    sd a0, 8(sp)
-; RV64-NEXT:    addi a1, sp, 40
+; RV64-NEXT:    addi a1, sp, 24
 ; RV64-NEXT:    addi a0, sp, 8
 ; RV64-NEXT:    addi s1, sp, 8
 ; RV64-NEXT:    call __clear_cache
@@ -59,7 +59,7 @@ define i64 @test0(i64 %n, ptr %p) nounwind {
 ; RV64-LINUX-NEXT:    slli a0, a0, 32
 ; RV64-LINUX-NEXT:    addi a0, a0, 919
 ; RV64-LINUX-NEXT:    sd a0, 8(sp)
-; RV64-LINUX-NEXT:    addi a1, sp, 40
+; RV64-LINUX-NEXT:    addi a1, sp, 24
 ; RV64-LINUX-NEXT:    addi a0, sp, 8
 ; RV64-LINUX-NEXT:    addi s1, sp, 8
 ; RV64-LINUX-NEXT:    li a2, 0