From ad41eacfb70e98e13cbfda076ded0c77b387ae8b Mon Sep 17 00:00:00 2001 From: Josh Kunz Date: Wed, 7 Aug 2019 11:40:50 -0700 Subject: Make gen-XX-const scripts work with llvm-as The gen-as-const and gen-py-const scripts are used to generate integer constant definitions from a list of constant C-expressions. This is achieved by generating a C program with inline `asm` statements, that depend on these constant expressions. During compilation, the constant expressions are evaluated, and included in the inline asm. The build process generates only the assembly, and then used `sed` to extract the values from the assembly text. This is clever. It allows the build process to extract the value of C statements built under the target architecture. The implementation is a bit fragile, but it is not immediately obvious to me how it could be improved. This change slightly modifies `gen-as-const` and `gen-py-const` to emit valid assembly directives instead of invalid directives that were previously emitted. Since the values are extracted via string parsing, this has no effect on the values extracted. This is needed because the LLVM assembler validates all statements before emitting them, whereas it appears GCC will literally emit any `asm` directives without validation or recognition. --- Makerules | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'Makerules') diff --git a/Makerules b/Makerules index 6528790..1bffdcc 100644 --- a/Makerules +++ b/Makerules @@ -260,7 +260,7 @@ $(py-const): $(py-const-dir)%.py: %.pysym $(py-const-script) \ $(common-before-compile) $(make-target-directory) $(AWK) -f $(py-const-script) $< \ - | $(CC) -S $(MOARFLAGS) -o $@.tmp $(CFLAGS) $(CPPFLAGS) -x c - + | $(CC) -S -o $@.tmp $(CFLAGS) $(CPPFLAGS) -x c - echo '# GENERATED FILE\n' > $@.tmp2 echo '# Constant definitions for pretty printers.' >> $@.tmp2 echo '# See gen-py-const.awk for details.\n' >> $@.tmp2 @@ -276,11 +276,10 @@ ifdef gen-as-const-headers # Generating headers for assembly constants. # We need this defined early to get into before-compile before # it's used in sysd-rules, below. -# clang's integrated assembler doesn't like the freaky tokens. $(common-objpfx)%.h $(common-objpfx)%.h.d: $(..)scripts/gen-as-const.awk \ %.sym $(common-before-compile) $(AWK) -f $< $(filter %.sym,$^) \ - | $(CC) -S $(MOARFLAGS) -o $(@:.h.d=.h)T3 $(CFLAGS) $(CPPFLAGS) -x c - \ + | $(CC) -S -o $(@:.h.d=.h)T3 $(CFLAGS) $(CPPFLAGS) -x c - \ -MD -MP -MF $(@:.h=.h.d)T -MT '$(@:.h=.h.d) $(@:.h.d=.h)' sed -n 's/^.*@@@name@@@\([^@]*\)@@@value@@@[^0-9Xxa-fA-F-]*\([0-9Xxa-fA-F-][0-9Xxa-fA-F-]*\).*@@@end@@@.*$$/#define \1 \2/p' \ $(@:.h.d=.h)T3 > $(@:.h.d=.h)T -- cgit v1.1