[LLVMdev] Apple's GCC and .s/.S files in llvm-test

Julien Lerouge jlerouge at apple.com
Fri Mar 21 10:59:09 PDT 2008


Apple's GCC does not make the distinction between .s and .S files and
always run the preprocessor. From the man:

|  file.s
|      Assembler code. Apple's version of GCC runs the preprocessor on these
|      files as well as those ending in .S.
|  file.S
|      Assembler code which must be preprocessed.

The problem is that sometimes llc generates comments in the assembly
that look like this for x86:

        pushl   %esi
	# implicit-def: EDI

The comment line is perfectly valid for the assembler, but the
preprocessor does not like it because it tries to interpret it as a
macro... I can see it happening for example if -std=c99 is set in the
CFLAGS (that's the case in SingleSource/Regression/C++) :

  $ gcc --std=c99  -o t t.s
  t.s:5:4: error: invalid preprocessing directive #implicit

One solution is to force the language to be assembler (and not
assembler-with-cpp) on Darwin, that's what the attached patch does, but
maybe there is a nicer solution ?


Julien Lerouge
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-------------- next part --------------
Index: Makefile.programs
--- Makefile.programs	(revision 48557)
+++ Makefile.programs	(working copy)
@@ -377,15 +377,25 @@
+# On darwin, Apple's GCC doesn't make a distinction between file.s and file.S,
+# it always run the preprocessor. One way to disable that is to force the
+# language to be assembler (not assembler-with-cpp).
+ifeq ($(OS),Darwin)
+FORCEASM = -x assembler
 # Assemble (and link) an LLVM-linked program using the system assembler...
 $(PROGRAMS_TO_TEST:%=Output/%.llc): \
 Output/%.llc: Output/%.llc.s
 $(PROGRAMS_TO_TEST:%=Output/%.llc-beta): \
 Output/%.llc-beta: Output/%.llc-beta.s

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