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Fix value profiling to record function pointer addresses instead of indices #2

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Fix value profiling to record function pointer addresses instead of indices #2

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2dd4595
Initial plan
Copilot Nov 10, 2025
b219465
Fix value profiling to record function pointer instead of index
Copilot Nov 10, 2025
c928a65
Add detailed comment explaining value profiling fix
Copilot Nov 10, 2025
d6c0011
Complete fix for value profiling
Copilot Nov 10, 2025
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1 change: 1 addition & 0 deletions _codeql_detected_source_root
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
.
19 changes: 11 additions & 8 deletions core/iwasm/compilation/aot_emit_function.c
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Expand Up @@ -2769,13 +2769,16 @@ aot_compile_op_call_indirect(AOTCompContext *comp_ctx, AOTFuncContext *func_ctx,
I32_CONST(1), /* 1 counter for this call site */
I32_CONST(0)); /* counter index 0 */

/* Now add value profiling to capture the call target */
/* Convert func_idx to i64 for value profiling */
LLVMValueRef func_idx_i64 = LLVMBuildZExt(comp_ctx->builder,
func_idx, I64_TYPE,
"func_idx_i64");
if (!func_idx_i64) {
aot_set_last_error("llvm build zext failed.");
/* Now add value profiling to capture the call target.
* LLVM's value profiling expects the actual function pointer address,
* not the WebAssembly function index. This allows LLVM to correlate
* the runtime target with the actual compiled function for PGO. */
/* Convert func_ptr to i64 for value profiling */
LLVMValueRef func_ptr_i64 = LLVMBuildPtrToInt(comp_ctx->builder,
func_ptr, I64_TYPE,
"func_ptr_i64");
if (!func_ptr_i64) {
aot_set_last_error("llvm build ptrtoint failed.");
goto fail;
}

Expand All @@ -2790,7 +2793,7 @@ aot_compile_op_call_indirect(AOTCompContext *comp_ctx, AOTFuncContext *func_ctx,
"llvm.instrprof.value.profile", VOID_TYPE,
value_prof_param_types, 5, glob,
I64_CONST(func_ctx->aot_func->func_idx),
func_idx_i64,
func_ptr_i64,
I32_CONST(0), /* IPVK_IndirectCallTarget */
I32_CONST(0)); /* call site index */
}
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