Improve QBE Backend Code Generation (Expand JS Support & IR Lowering)

[ronak-create]

Description

Currently, the compiler parses string literals but does not lower them in the QBE backend. This prevents basic programs like:

console.log("hello");

from working correctly.

This issue focuses on adding basic string literal support in the QBE backend by emitting them into the .data section and referencing them in generated code.

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Goal

Enable simple string output via console.log by supporting string literals in QBE code generation.

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Tasks

• Detect string literals during QBE codegen
• Store string literals in a global table (avoid duplicates if possible)
• Emit .data section entries in QBE IR
• Generate labels for each string (e.g., str0, str1)
• Replace string usage in code with label references
• Update console.log lowering to handle string arguments

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Expected Behavior

Input:

console.log("hello");

QBE IR (simplified idea):

data $str0 = { b "hello", b 0 }
export function w $main() {

@start

call $puts(l $str0)

ret 0

}

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Hints

• Look into: src/qbe/qbe_codegen.c
• You may need:
  • A small string pool (array or hashmap)
  • A helper like: get_string_label(const char* str)
• QBE uses null-terminated strings (b 0)

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Scope

• Only handle string literals
• No need for:
  • String operations
  • Concatenation
  • Dynamic allocation

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Why This Matters

• Unlocks basic I/O capability
• First step toward real JS support
• Clean, self-contained backend improvement

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Difficulty

🟢 Good First Issue

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Status

Open for contribution