Author: he32 Date: 2026-09-20T23:32:59Z New Revision: c1b15b54ee18d35be275f04de1a5d0c5d1cd67e3
URL: https://github.com/llvm/llvm-project/commit/c1b15b54ee18d35be275f04de1a5d0c5d1cd67e3 DIFF: https://github.com/llvm/llvm-project/commit/c1b15b54ee18d35be275f04de1a5d0c5d1cd67e3.diff LOG: [M68k][NetBSD] Fix alignments for NetBSD/m68k. (#207602) Linux/m68k uses the ABI from Sun Microsystems for a.out on m68k, which aligns ints/objects/pointers/stack on 16-bit boundaries. NetBSD/m68k on the other hand uses the ABI from SVR4 for m68k, which aligns ints/objects/pointers/stack on 32-bit boundaries. This is a follow-up of https://github.com/M680x0/issues/issues/13 Added: Modified: clang/lib/Basic/Targets/M68k.cpp llvm/lib/TargetParser/TargetDataLayout.cpp Removed: ################################################################################ diff --git a/clang/lib/Basic/Targets/M68k.cpp b/clang/lib/Basic/Targets/M68k.cpp index fde1e3953a6c0..87da5849f35f7 100644 --- a/clang/lib/Basic/Targets/M68k.cpp +++ b/clang/lib/Basic/Targets/M68k.cpp @@ -24,6 +24,18 @@ namespace clang { namespace targets { +// Linux/m68k ("old") uses the ABI from Sun Microsystems a.out +// for m68k, and uses 16-bit alignments for int/long/pointers. +// +// NetBSD/m68k uses the ABI from SVR4 for m68k, +// which uses 32-bit alignments for int/long/pointers. +// +// Ref. https://github.com/M680x0/issues/issues/13 and +// https://github.com/llvm/llvm-project/issues/199826 +// +// Arguably this ought to respect -malign-int, as suggested +// above, this code doesn't so far. + M68kTargetInfo::M68kTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts) : TargetInfo(Triple), TargetOpts(Opts) { @@ -32,7 +44,11 @@ M68kTargetInfo::M68kTargetInfo(const llvm::Triple &Triple, SizeType = UnsignedInt; PtrDiffType = SignedInt; IntPtrType = SignedInt; - IntAlign = LongAlign = PointerAlign = 16; + if (getTriple().isOSNetBSD()) { + IntAlign = LongAlign = PointerAlign = 32; + } else { + IntAlign = LongAlign = PointerAlign = 16; + } } bool M68kTargetInfo::setCPU(StringRef Name) { diff --git a/llvm/lib/TargetParser/TargetDataLayout.cpp b/llvm/lib/TargetParser/TargetDataLayout.cpp index c4de5d50bb8e3..83bc4a624bf99 100644 --- a/llvm/lib/TargetParser/TargetDataLayout.cpp +++ b/llvm/lib/TargetParser/TargetDataLayout.cpp @@ -120,6 +120,17 @@ static std::string computeLoongArchDataLayout(const Triple &TT) { return "e-m:e-p:32:32-i64:64-n32-S128"; } +// The Linux m68k target uses the ABI used +// by Sun Microsystems for the old a.out-based binaries: 16-bit +// alignment of int/long/pointer. +// +// NetBSD/m68k on the other hand uses the SVR4 ABI, which +// aligns int/long/pointer/objects/stack on 32-bit boundaries. +// +// For now we just fix this for NetBSD/m68k. +// +// Ref. https://github.com/llvm/llvm-project/issues/199826 + static std::string computeM68kDataLayout(const Triple &TT) { std::string Ret = ""; // M68k is Big Endian @@ -128,22 +139,36 @@ static std::string computeM68kDataLayout(const Triple &TT) { // FIXME how to wire it with the used object format? Ret += "-m:e"; - // M68k pointers are always 32 bit wide even for 16-bit CPUs. - // The ABI only specifies 16-bit alignment. - // On at least the 68020+ with a 32-bit bus, there is a performance benefit - // to having 32-bit alignment. - Ret += "-p:32:16:32"; + if (!TT.isOSNetBSD()) { + // M68k pointers are always 32 bit wide even for 16-bit CPUs. + // The ABI only specifies 16-bit alignment. + // On at least the 68020+ with a 32-bit bus, there is a performance benefit + // to having 32-bit alignment. + Ret += "-p:32:16:32"; - // Bytes do not require special alignment, words are word aligned and - // long words are word aligned at minimum. - Ret += "-i8:8:8-i16:16:16-i32:16:32"; + // Bytes do not require special alignment, words are word aligned and + // long words are word aligned at minimum. + Ret += "-i8:8:8-i16:16:16-i32:16:32"; - // FIXME no floats at the moment + // The registers can hold 8, 16, 32 bits + Ret += "-n8:16:32"; - // The registers can hold 8, 16, 32 bits - Ret += "-n8:16:32"; + Ret += "-a:0:16-S16"; + } else { + // NetBSD/m68k aligns long/pointer/stack/objects on 32-bits, + // ref. comment above. + Ret += "-p:32:32:32"; + // Bytes do not require special alignment, + // 16-bit ints are 16-bit aligned and + // 32-bit ints are 32-bit aligned + Ret += "-i8:8:8-i16:16:16-i32:32:32"; + // The registers can hold 8, 16, 32 bits + Ret += "-n8:16:32"; + // object and stack alignment is also 32 bits + Ret += "-a:0:32-S32"; + } - Ret += "-a:0:16-S16"; + // FIXME no floats at the moment return Ret; } _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
