[profile] Only use NT_GNU_BUILD_ID if supported

The Solaris buildbots have been broken for some time by the unconditional
use of `NT_GNU_BUILD_ID`, e.g. Solaris/sparcv9
<https://lab.llvm.org/staging/#/builders/50/builds/4910> and Solaris/amd64
<https://lab.llvm.org/staging/#/builders/101/builds/3751>.  Being a GNU
extension, it is not defined in `<sys/elf.h>`.  However, providing a
fallback definition doesn't help because the code also relies on
`__ehdr_start`, another unportable GNU extension that most likely never
will be implemented in Solaris `ld`.  Besides, there's reallly no point in
supporting build ids since they aren't used on Solaris at all.

This patch fixes this by making the relevant code conditional on the
definition of `NT_GNU_BUILD_ID`.

Tested on `amd64-pc-solaris2.11` and `sparcv9-sun-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D107556

diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
index d1922e2..7c15f97 100644 (file)
--- a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
@@ -85,6 +85,7 @@ COMPILER_RT_VISIBILITY ValueProfNode *__llvm_profile_end_vnodes(void) {
 COMPILER_RT_VISIBILITY ValueProfNode *CurrentVNode = &PROF_VNODES_START;
 COMPILER_RT_VISIBILITY ValueProfNode *EndVNode = &PROF_VNODES_STOP;
 
+#ifdef NT_GNU_BUILD_ID
 static size_t RoundUp(size_t size, size_t align) {
   return (size + align - 1) & ~(align - 1);
 }
@@ -188,5 +189,14 @@ COMPILER_RT_VISIBILITY int __llvm_write_binary_ids(ProfDataWriter *Writer) {
 
   return 0;
 }
+#else /* !NT_GNU_BUILD_ID */
+/*
+ * Fallback implementation for targets that don't support the GNU
+ * extensions NT_GNU_BUILD_ID and __ehdr_start.
+ */
+COMPILER_RT_VISIBILITY int __llvm_write_binary_ids(ProfDataWriter *Writer) {
+  return 0;
+}
+#endif
 
 #endif