test(native): add internal-assembler conformance guard
Neither fixpoint exercises the in-process internal assembler (--assembler internal): fixpoint.sh assembles via qbe+gcc, fixpoint-native.sh assembles the native .s with gcc. A miscompilation that only corrupts the internal assembler's object output therefore passes both fixpoints cleanly — which is exactly how the sret-Result field-read bug (fixed in the previous commit) escaped the fixpoint gate. scripts/fixpoint-native-internal.sh closes that gap. It compiles a small representative program (record-returning function with sret-Result field reads, plus immutable string literals) with BOTH --assembler internal and --assembler external, then asserts the two binaries behave identically (stdout + exit code). Behavioural equivalence is the sound invariant: the two assemblers may emit different-but-valid encodings, so a byte-level section compare would false-positive. A true self-hosting internal-assembler fixpoint (compile the compiler with itself via --assembler internal) is deferred: the internal assembler buffers the whole object in memory and needs ~53 GB for the compiler's own 631k-line .s, OOM-killing. That scalability limit is tracked in bugs.txt; until the assembler streams its output, this differential conformance check plus TInternalAsmE2ETests are the internal-assembler guards. Verified: prints NATIVE_INTERNAL_OK on a fixed compiler, exits non-zero with EXIT_MISMATCH on a compiler carrying the sret-Result bug.
This commit is contained in:
Graeme Geldenhuys
parent
eee7f54284
commit
0631bb0cdf
143
scripts/fixpoint-native-internal.sh
Executable file
143
scripts/fixpoint-native-internal.sh
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#!/bin/bash
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# Internal-assembler conformance check for the Blaise self-hosting toolchain.
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#
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# WHY THIS EXISTS, separately from fixpoint-native.sh:
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# fixpoint-native.sh validates native CODEGEN by diffing the emitted .s
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# text, but it assembles that text with the EXTERNAL assembler (gcc).
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# The in-process internal assembler (blaise.assembler.x86_64, reached via
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# --assembler internal) is a DIFFERENT .s -> object path that NEITHER
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# fixpoint exercises. A miscompilation that only corrupts the internal
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# assembler's object output therefore passes both fixpoints cleanly
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# (this is exactly how the sret-Result field-read bug hid; see bugs.txt
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# 2026-06-16).
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#
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# WHY THIS IS A DIFFERENTIAL CHECK, NOT A SELF-HOSTING FIXPOINT:
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# The internal assembler currently buffers the whole assembly + ELF
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# object in memory, so assembling the compiler's own ~631k-line .s needs
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# ~53 GB and OOM-kills. A true "compile the compiler with itself via
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# --assembler internal" fixpoint is therefore not feasible until the
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# internal assembler streams its output. Instead we compile a
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# representative program that exercises the bug-prone paths (record-return
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# sret-Result field reads, immutable string literals) BOTH ways and assert
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# the internal-assembler binary BEHAVES identically (stdout + exit code) to
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# the trusted external-assembler binary. Note: the two assemblers may emit
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# different-but-valid encodings, so a byte-level section compare would
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# false-positive; behavioural equivalence is the sound invariant.
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#
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# Requires: a native compiler at compiler/target/blaise (run the QBE
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# fixpoint or `pasbuild compile` first) and compiler/target/blaise_rtl.a.
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set -e
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if [ ! -f "compiler/src/main/pascal/Blaise.pas" ]; then
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echo "Run this script from the project root: ./scripts/fixpoint-native-internal.sh" >&2
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exit 1
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fi
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COMPILER="${1:-compiler/target/blaise}"
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if [ ! -x "$COMPILER" ]; then
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echo "Compiler not found: $COMPILER" >&2
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echo "Build it first: pasbuild compile -m blaise-compiler --compiler ..." >&2
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exit 10
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fi
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if [ -f compiler/target/blaise_rtl.a ]; then
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RTL_ARCHIVE=compiler/target/blaise_rtl.a
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elif [ -f runtime/target/blaise_rtl.a ]; then
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RTL_ARCHIVE=runtime/target/blaise_rtl.a
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else
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echo "blaise_rtl.a not found — build the runtime first" >&2
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exit 11
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fi
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# FindRTL looks for blaise_rtl.a beside the compiler binary.
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cp "$RTL_ARCHIVE" "$(dirname "$COMPILER")/blaise_rtl.a" 2>/dev/null || true
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UNIT_ARGS="--unit-path runtime/src/main/pascal --unit-path stdlib/src/main/pascal"
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PROBE=/tmp/fpni_probe.pas
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# Representative program. Exercises the sret-Result field-read path (a
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# record-returning function reads one Result field into another) plus many
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# immutable string literals (each emits a `.long -1` header the internal
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# assembler must encode correctly).
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cat > "$PROBE" <<'PROBE_EOF'
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program fpni_probe;
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type
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TPoint = record
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X: Int64;
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Y: Int64;
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Name: string;
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end;
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function MakePoint(AX, AY: Int64; const AName: string): TPoint;
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begin
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Result.X := AX;
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Result.Y := AY;
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Result.Name := AName;
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if Result.X >= Result.Y then
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Result.Name := AName + '-wide'
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else
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Result.Name := AName + '-tall';
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end;
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var
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P: TPoint;
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I: Integer;
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Total: Int64;
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begin
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Total := 0;
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for I := 0 to 4 do
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begin
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P := MakePoint(I, I * 2, 'pt');
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Total := Total + P.X + P.Y;
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WriteLn(P.Name, ' ', P.X, ',', P.Y);
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end;
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WriteLn('total=', Total);
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WriteLn('immutable string literals and record return survived');
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end.
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PROBE_EOF
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echo "compiler: $COMPILER"
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echo "[1/3] compile probe with INTERNAL assembler"
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if ! "$COMPILER" --source "$PROBE" $UNIT_ARGS \
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--backend native --assembler internal --output /tmp/fpni_int 2>/tmp/fpni_int.err; then
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echo "INTERNAL_COMPILE_FAIL"; head -5 /tmp/fpni_int.err; exit 2
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fi
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echo "[2/3] compile probe with EXTERNAL assembler (reference)"
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if ! "$COMPILER" --source "$PROBE" $UNIT_ARGS \
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--backend native --assembler external --output /tmp/fpni_ext 2>/tmp/fpni_ext.err; then
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echo "EXTERNAL_COMPILE_FAIL"; head -5 /tmp/fpni_ext.err; exit 3
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fi
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echo "[3/3] run both and compare stdout + exit code"
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# Behavioural equivalence is the sound invariant: the internal and external
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# assemblers may emit DIFFERENT-but-valid encodings for the same .s (so a
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# byte-level .text/.rodata compare would false-positive), but a binary built
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# by the internal assembler must BEHAVE identically to the external-assembler
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# reference. The sret-Result bug broke exactly this (corrupted string
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# headers => wrong / garbage output), so stdout + exit code catch it.
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# Disable -e around the runs: a miscompiled internal binary may crash
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# (e.g. SIGSEGV from a corrupted string header), and we must REPORT that as
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# a guard failure rather than let -e abort the script mid-diagnostic.
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set +e
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/tmp/fpni_int > /tmp/fpni_int.out 2>&1; INT_RC=$?
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/tmp/fpni_ext > /tmp/fpni_ext.out 2>&1; EXT_RC=$?
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set -e
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if [ "$INT_RC" -ne "$EXT_RC" ]; then
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echo "EXIT_MISMATCH internal=$INT_RC external=$EXT_RC"
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echo " (internal-assembler binary misbehaved — likely a codegen/assembler regression)"
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echo "--- internal stdout ---"; cat /tmp/fpni_int.out
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echo "--- external stdout ---"; cat /tmp/fpni_ext.out
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exit 6
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fi
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if ! diff -q /tmp/fpni_int.out /tmp/fpni_ext.out >/dev/null; then
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echo "OUTPUT_MISMATCH (internal assembler produced a binary that behaves differently)"
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echo "--- internal ---"; cat /tmp/fpni_int.out
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echo "--- external ---"; cat /tmp/fpni_ext.out
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exit 6
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fi
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echo "NATIVE_INTERNAL_OK"
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exit 0
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