8l: Windows 386 PE that prints via kernel32 (-H 10)#7
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Wire the PE writer into 6l so it can produce 64-bit Windows executables
that actually do I/O, the amd64 counterpart to the 386 support on 8l.
src/cmd/ld/pe.{c,h}: add the PE32+ path.
- New IMAGE_OPTIONAL_HEADER64 (ImageBase and the stack/heap sizes widen
to 8 bytes, BaseOfData dropped; written verbatim like the 32-bit
header). peinit() already set pe64 for thechar=='6'; asmbpe() now
emits Magic 0x20b, MajorSubsystem/OS 6.0 (64-bit Windows predates
4.0), LARGE_ADDRESS_AWARE, and fills oh64 from oh.
- The import table now imports GetStdHandle, WriteFile and ExitProcess
from kernel32. peimports() (run from dope(), before reloc()) lays out
the .idata section and defines an __imp_<name> linker symbol at each
import's IAT slot, so a program can call through the thunk with
"MOVQ __imp_WriteFile(SB), AX; CALL AX". IAT entries and the null
terminator are 8 bytes wide under pe64.
- add_import_table() now only writes the bytes (layout done earlier),
and writes them at the section's PointerToRawData rather than the
current EOF (with non-empty .data the file position is not
page-aligned, which left the image "truncated").
- dope() skips zero-size .data/.bss: an empty section does not advance
the virtual-address cursor, so the next section would collide on
VirtualAddress and the loader rejects the image.
src/cmd/6l: compile pe.c (symlink + mkfile), add "-H 10" / goos=windows
handling in obj.c (peinit + case 10, defaulting INITTEXT=PEBASE+0x1000
like 8l), call dope() before reloc() so the __imp_* symbols resolve, and
dispatch asmbpe() from asmb(). 6l has no PE symbol-table path yet, so
obj.c forces -s for -H 10.
tests/s/mini: hello_windows_amd64.s prints "Hello, World!" via
GetStdHandle + WriteFile + ExitProcess (Win64 ABI: args in CX/DX/R8/R9,
32-byte shadow space, 16-byte aligned stack), built with 6l -H 10.
Verified on Linux with wine: `6l -s -H 10` produces a
"PE32+ executable (console) x86-64" (Magic 0x20b, ImageBase 0x400000)
that prints "Hello, World!" and exits 0.
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Builds on the shared PE import machinery added for amd64: hook 8l up so a 386 PE can call into kernel32 and print, the counterpart to the 6l amd64 support. src/cmd/8l/obj.c: call dope() before reloc() (not after) so the __imp_<name> import symbols defined while laying out .idata resolve during relocation; force -s for -H 10 (asmbpe() would otherwise emit a .symdat section after .idata and perturb the layout; matches 6l). tests/s/mini: hello_windows_386.s now prints "Hello, World!" via GetStdHandle + WriteFile + ExitProcess instead of just returning. It uses the Win32 __stdcall convention (args on the stack right-to-left, callee pops them). The argument area is reserved with SUBL and filled with MOVL rather than PUSHL: 8l statically balances PUSH/POP within a function and cannot see that the callee pops, so PUSHL trips "unbalanced PUSH/POP". The import thunk is called indirectly (MOVL __imp_WriteFile(SB), AX; CALL AX) because a direct "CALL sym(SB)" is rejected by patch() for non-text targets. mkfile: build hello_windows_386.exe with 8l_ -s -H 10 and enable it in WINDOWSBINS alongside amd64. Verified on Linux with wine: `8l_ -s -H 10` produces a "PE32 executable (console) Intel 80386" that prints "Hello, World!" and exits 0.
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Summary
8l_ -H 10) now prints to the console instead of just returning.8l's pass order and makeshello_windows_386.scallGetStdHandle+WriteFile+ExitProcessusing the shared PE import machinery.Details
src/cmd/8l/obj.c: calldope()beforereloc()so the__imp_*import symbols resolve; force-sfor-H 10(avoids a.symdatsection that would perturb the import layout; matches6l).hello_windows_386.s: prints via the Win32__stdcallconvention. The arg area is reserved withSUBL/MOVLrather thanPUSHLbecause8lstatically balances PUSH/POP and can't see the callee pop. Thunks are called indirectly (MOVL __imp_WriteFile(SB), AX; CALL AX).mkfile: build with8l_ -s -H 10, enabled inWINDOWSBINSalongside amd64.Stacking (please read)
This PR is stacked on top of #8 and, because GitHub cross-fork PRs can't use a fork branch as base, its diff also contains #8's commit (
6l: PE32+ output for Windows amd64). The 386 printing reuses the shared kernel32 import machinery that #8 introduces insrc/cmd/ld/pe.c. Please review/merge #8 first; then this PR reduces to just the8lcommit. (Happy to squash both into one PR if you prefer.)Test plan
8l_ -s -H 10builds aPE32 executable (console) Intel 80386.wine: printsHello, World!, exits 0.mk allintests/s/minipasses; plan9 386 (-H 2) path unaffected.