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cmd/link: generate .pdata PE section

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This CL adds a .pdata section to the PE file generated by the Go linker.

The .pdata section is a standard section [1] that contains an array of
function table entries that are used for stack unwinding.
The table entries layout is taken from [2].

This CL just generates the table entries without any unwinding
information, which is enough to start doing some E2E tests
between the Go linker and the Win32 APIs.

The goal of the .pdata table is to allow Windows retrieve
unwind information for a function at a given PC. It does so by doing
a binary search on the table, looking for an entry that meets
BeginAddress >= PC < EndAddress.

Each table entry takes 12 bytes and only non-leaf functions with
frame pointer needs an entry on the .pdata table.
The result is that PE binaries will be ~0.7% bigger due to the unwind
information, a reasonable amount considering the benefits in
debuggability.

Updates #57302

[1] https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#the-pdata-section
[2] https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-runtime_function

Change-Id: If675d10c64452946dbab76709da20569651e3e9f
Reviewed-on: https://go-review.googlesource.com/c/go/+/461738
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
qmuntal 2023-01-17 08:15:33 +01:00 • committed by Quim Muntal
parent 53279a6af3
commit 14cf82aa37
16 changed files with 237 additions and 5 deletions
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10
src/cmd/link/internal/loader/loader.go
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@ -1646,6 +1646,16 @@ func (l *Loader) WasmImportSym(fnSymIdx Sym) (Sym, bool) {
return 0, false
}
// SEHUnwindSym returns the auxiliary SEH unwind symbol associated with
// a given function symbol.
func (l *Loader) SEHUnwindSym(fnSymIdx Sym) Sym {
if l.SymType(fnSymIdx) != sym.STEXT {
log.Fatalf("error: non-function sym %d/%s t=%s passed to SEHUnwindSym", fnSymIdx, l.SymName(fnSymIdx), l.SymType(fnSymIdx).String())
}
return l.aux1(fnSymIdx, goobj.AuxSehUnwindInfo)
}
// GetFuncDwarfAuxSyms collects and returns the auxiliary DWARF
// symbols associated with a given function symbol. Prior to the
// introduction of the loader, this was done purely using name