compiler, libgo: support bootstrapping gc compiler

In the Go 1.21 release the package internal/profile imports
internal/lazyregexp.  That works when bootstrapping with Go 1.17,
because that compiler has internal/lazyregep and permits importing it.
We also have internal/lazyregexp in libgo, but since it is not installed
it is not available for importing.  This CL adds internal/lazyregexp
to the list of internal packages that are installed for bootstrapping.

The Go 1.21, and earlier, releases have a couple of functions in
the internal/abi package that are always fully intrinsified.
The gofrontend recognizes and intrinsifies those functions as well.
However, the gofrontend was also building function descriptors
for references to the functions without calling them, which
failed because there was nothing to refer to.  That is OK for the
gc compiler, which guarantees that the functions are only called,
not referenced.  This CL arranges to not generate function descriptors
for these functions.

For golang/go#60913

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/504798

1 files changed, 2 insertions, 8 deletions

diff --git a/libgo/go/internal/abi/abi.go b/libgo/go/internal/abi/abi.go
index c4a1088..6625127 100644
--- a/libgo/go/internal/abi/abi.go
+++ b/libgo/go/internal/abi/abi.go
@@ -17,10 +17,7 @@ package abi
 // compile-time error.
 //
 // Implemented as a compile intrinsic.
-func FuncPCABI0(f any) uintptr {
-	// The compiler should remove all calls.
-	panic("FuncPCABI0")
-}
+func FuncPCABI0(f any) uintptr
 
 // FuncPCABIInternal returns the entry PC of the function f. If f is a
 // direct reference of a function, it must be defined as ABIInternal.
@@ -29,7 +26,4 @@ func FuncPCABI0(f any) uintptr {
 // the behavior is undefined.
 //
 // Implemented as a compile intrinsic.
-func FuncPCABIInternal(f any) uintptr {
-	// The compiler should remove all calls.
-	panic("FuncPCABIInternal")
-}
+func FuncPCABIInternal(f any) uintptr