[Analysis] Disable calls to *_finite and other glibc-only functions on Android.

[chh]

Summary

Since r322087, glibc's finite lib calls are generated when possible.
However, they are not supported on Android. This change also
disables other functions not available on Android.

[efriedma]

lib/Analysis/TargetLibraryInfo.cpp

400–402

Instead of going through this process repeatedly, could we just change this line to "if (!T.isOSLinux() || T.isAndroid())"?

[srhines]

lib/Analysis/TargetLibraryInfo.cpp

400–402

I agree that we should just be nuking all of the *_finite() functions, but many of these other functions are indeed available on Android, so we can't just change this single guard here.

Chih-hung, we should follow up with the bionic folks to ensure that these functions are available for all NDK platforms too. In cases like fseeko64/etc., where it only appears in API level 24, it also wouldn't be correct to lower to any of these libcalls for a target API level < 24.

[minseong.kim]

lib/Analysis/TargetLibraryInfo.cpp

400–402

In terms of having the separate list of unsupported libcalls for Android, it looks reasonable to me as the two lists of libcalls might not be exactly the same now and in the future.

[chh]

lib/Analysis/TargetLibraryInfo.cpp

400–402

I keep only the memalign function, which is available on Android.

[efriedma]

lib/Analysis/TargetLibraryInfo.cpp

401

Maybe instead of !T.isOSLinux() || T.isAndroid(), this should be !T.isOSLinux() || !T.isGNUEnvironment(), so it's clear this is the set of functions specifically available on glibc?

410

If would probably be more clear to write this as "if (!T.isAndroid())". Or maybe move this out into its own if statement.

[chh]

lib/Analysis/TargetLibraryInfo.cpp

401

I tried to use !T.isGNUEnvironment() instead of T.isAndroid().
The Transforms/InferFunctionAttrs/annotate.ll test failed because it expects x86_64-unknown-linux to be treated as isOSLinux() here.
I am not sure which clang targets use unknown-linux plus glibc.
Shall we only limit Android target for now?

[efriedma]

lib/Analysis/TargetLibraryInfo.cpp

401

Oh, didn't think of that.

Sure, let's limit to Android for now.

[efriedma]

LGTM

lib/Analysis/TargetLibraryInfo.cpp

static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
   // http://svn.freebsd.org/base/head/lib/libc/string/flsl.c
   // http://svn.freebsd.org/base/head/lib/libc/string/flsll.c
   if (!T.isOSFreeBSD()) {
     TLI.setUnavailable(LibFunc_fls);
     TLI.setUnavailable(LibFunc_flsl);
     TLI.setUnavailable(LibFunc_flsll);
   }
 
-  // Android uses bionic instead of glibc. So disable some finite
-  // lib calls in glibc for Android. The list of unsupported lib
-  // calls for Android may expand as the need arises.
-  if (T.isAndroid()) {
-    TLI.setUnavailable(LibFunc_exp_finite);
-    TLI.setUnavailable(LibFunc_exp2_finite);
-    TLI.setUnavailable(LibFunc_pow_finite);
-  }
-
-  // The following functions are available on at least Linux:
-  if (!T.isOSLinux()) {
+  // The following functions are available on Linux,
+  // but Android uses bionic instead of glibc.
+  if (!T.isOSLinux() || T.isAndroid()) {
     TLI.setUnavailable(LibFunc_dunder_strdup);
     TLI.setUnavailable(LibFunc_dunder_strtok_r);
     TLI.setUnavailable(LibFunc_dunder_isoc99_scanf);
     TLI.setUnavailable(LibFunc_dunder_isoc99_sscanf);
     TLI.setUnavailable(LibFunc_under_IO_getc);
     TLI.setUnavailable(LibFunc_under_IO_putc);
+    // Android has memalign.
+    if (!T.isOSLinux())
       TLI.setUnavailable(LibFunc_memalign);
     TLI.setUnavailable(LibFunc_fopen64);
     TLI.setUnavailable(LibFunc_fseeko64);
     TLI.setUnavailable(LibFunc_fstat64);
     TLI.setUnavailable(LibFunc_fstatvfs64);
     TLI.setUnavailable(LibFunc_ftello64);
     TLI.setUnavailable(LibFunc_lstat64);
     TLI.setUnavailable(LibFunc_open64);
     TLI.setUnavailable(LibFunc_stat64);

test/CodeGen/AArch64/illegal-float-ops.ll

define void @test_exp2_finite(double %double) #0 {
   %expdouble = call double @llvm.exp2.f64(double %double)
   store double %expdouble, double* @vardouble
   ; ANDROID-AARCH64-NOT: bl __exp2_finite
   ; CHECK: bl __exp2_finite
 
   ret void
 }
 
+define void @test_log_finite(double %double) #0 {
+  %logdouble = call double @llvm.log.f64(double %double)
+  store double %logdouble, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __log_finite
+  ; CHECK: bl __log_finite
+  ret void
+}
+
+define void @test_log2_finite(double %double) #0 {
+  %log2double = call double @llvm.log2.f64(double %double)
+  store double %log2double, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __log2_finite
+  ; CHECK: bl __log2_finite
+  ret void
+}
+
+define void @test_log10_finite(double %double) #0 {
+  %log10double = call double @llvm.log10.f64(double %double)
+  store double %log10double, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __log10_finite
+  ; CHECK: bl __log10_finite
+  ret void
+}
+
 define void @test_pow_finite(double %double) #0 {
   %powdouble = call double @llvm.pow.f64(double %double, double %double)
   store double %powdouble, double* @vardouble
   ; ANDROID-AARCH64-NOT: bl __pow_finite
   ; CHECK: bl __pow_finite
   ret void
 }
 
 attributes #0 = { "no-infs-fp-math"="true" "no-nans-fp-math"="true" }