[lldb-dev] r260768 (Removed many JIT workarounds from IRForTarget) broke expression parser with function on Hexagon

[Sean Callanan via lldb-dev]

Ted,

I’m not sure who inside Clang actually sets the value ID – it’s the code generator’s job to make IR, we don’t construct it.
I would be fine with adding FunctionVal to the switch in CanResolveConstant, returning true.

Sean

> On Feb 23, 2016, at 3:28 PM, Ted Woodward <ted.woodward at codeaurora.org> wrote:
> 
> Background: Hexagon clang doesn’t have JIT support, so lldb for Hexagon only uses the IR Interpreter (Codeplay wrote it for us).
>  
> Sean, r260768 broke the expression parser with functions.
>  
> Without connecting to a target, I can’t get the info for main:
> (lldb) e main
> error: Can't run the expression locally: Interpreter doesn't handle one of the expression's operands
>  
> Connected to a target, I can’t run a function:
> (lldb) e factorial(5)
> error: Can't run the expression locally: Interpreter doesn't handle one of the expression's operands
>  
>  
> I’ve traced the failure to the call to CanResolveConstant() in IRInterpreter::CanIntepret(). The failure happens on the 2nd operand. In the working case, the Value ID is 0xa – Value::ConstantExprVal. In the failing case, it is 0x5. Since it’s defined in a .def file, I can’t be sure, but my guess is its Value::FunctionVal.
>  
>  
> Where is the Value ID set?
>  
>  
>  
> Some info from the expr log:
>  
> ; Function Attrs: nounwind
> define void @"_Z12$__lldb_exprPv"(i8* %"$__lldb_arg") #0 {
> entry:
>   %"$__lldb_arg.addr" = alloca i8*, align 4, !clang.decl.ptr !4
>   store i8* %"$__lldb_arg", i8** %"$__lldb_arg.addr", align 4
>   %0 = load i8, i8* @"_ZGVZ12$__lldb_exprPvE19$__lldb_expr_result", align 1
>   %guard.uninitialized = icmp eq i8 %0, 0
>   br i1 %guard.uninitialized, label %init.check, label %init.end
>  
> init.check:                                       ; preds = %entry
>   %call = call i32 @factorial(i32 5)
>   store i32 %call, i32* @"_ZZ12$__lldb_exprPvE19$__lldb_expr_result", align 4
>   store i8 1, i8* @"_ZGVZ12$__lldb_exprPvE19$__lldb_expr_result", align 1
>   br label %init.end
>  
> init.end:                                         ; preds = %init.check, %entry
>   ret void
> }
>  
>  
> Unsupported constant: declare i32 @factorial(i32) #1
>  
>  
> Ted
>  
> --
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

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