glibc: fix build with -O

* tested for qemuarm, qemux86 with -O, -O0, -Os, with gcc
* to build with -O0 I had to remove restriction from systemtap first

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 167 insertions, 0 deletions

diff --git a/meta/recipes-core/glibc/glibc/0031-sysdeps-ieee754-prevent-maybe-uninitialized-errors.patch b/meta/recipes-core/glibc/glibc/0031-sysdeps-ieee754-prevent-maybe-uninitialized-errors.patch
new file mode 100644
index 0000000000..b02c4ec94f
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/0031-sysdeps-ieee754-prevent-maybe-uninitialized-errors.patch
@@ -0,0 +1,95 @@
+From c6cc5a6ef46837e341fe271b5ffa6def23810082 Mon Sep 17 00:00:00 2001
+From: Martin Jansa <Martin.Jansa@gmail.com>
+Date: Fri, 14 Sep 2018 23:23:03 +0000
+Subject: [PATCH] sysdeps/ieee754: prevent maybe-uninitialized errors
+
+* with -O included in BUILD_OPTIMIZATION when DEBUG_BUILD
+  is used, nativesdk-glibc fails with:
+../sysdeps/ieee754/ldbl-96/e_jnl.c: In function '__ieee754_jnl':
+../sysdeps/ieee754/ldbl-96/e_jnl.c:146:20: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+      b = invsqrtpi * temp / sqrtl (x);
+          ~~~~~~~~~~^~~~~~
+../sysdeps/ieee754/ldbl-96/e_jnl.c: In function '__ieee754_ynl':
+../sysdeps/ieee754/ldbl-96/e_jnl.c:375:16: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+  b = invsqrtpi * temp / sqrtl (x);
+      ~~~~~~~~~~^~~~~~
+
+* work around the issue instead of removing -O like we do with
+  SELECTED_OPTIMIZATION
+
+Upstream-Status: Submitted [https://www.sourceware.org/ml/libc-alpha/2018-09/msg00299.html]
+
+Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
+---
+ sysdeps/ieee754/dbl-64/e_jn.c    | 2 ++
+ sysdeps/ieee754/ldbl-128/e_jnl.c | 4 ++++
+ sysdeps/ieee754/ldbl-96/e_jnl.c  | 4 ++++
+ 3 files changed, 10 insertions(+)
+
+diff --git a/sysdeps/ieee754/dbl-64/e_jn.c b/sysdeps/ieee754/dbl-64/e_jn.c
+index 9181b22bb8..74a6b5f149 100644
+--- a/sysdeps/ieee754/dbl-64/e_jn.c
++++ b/sysdeps/ieee754/dbl-64/e_jn.c
+@@ -108,6 +108,7 @@ __ieee754_jn (int n, double x)
+ 	      case 1: temp = -c + s; break;
+ 	      case 2: temp = -c - s; break;
+ 	      case 3: temp = c - s; break;
++	      default: temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	      }
+ 	    b = invsqrtpi * temp / sqrt (x);
+ 	  }
+@@ -315,6 +316,7 @@ __ieee754_yn (int n, double x)
+ 	  case 1: temp = -s - c; break;
+ 	  case 2: temp = -s + c; break;
+ 	  case 3: temp = s + c; break;
++	  default: temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	  }
+ 	b = invsqrtpi * temp / sqrt (x);
+       }
+diff --git a/sysdeps/ieee754/ldbl-128/e_jnl.c b/sysdeps/ieee754/ldbl-128/e_jnl.c
+index 7739eec291..b6a1275464 100644
+--- a/sysdeps/ieee754/ldbl-128/e_jnl.c
++++ b/sysdeps/ieee754/ldbl-128/e_jnl.c
+@@ -149,6 +149,8 @@ __ieee754_jnl (int n, _Float128 x)
+ 	      case 3:
+ 		temp = c - s;
+ 		break;
++	      default:
++	        temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	      }
+ 	    b = invsqrtpi * temp / sqrtl (x);
+ 	  }
+@@ -385,6 +387,8 @@ __ieee754_ynl (int n, _Float128 x)
+ 	  case 3:
+ 	    temp = s + c;
+ 	    break;
++	  default:
++	    temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	  }
+ 	b = invsqrtpi * temp / sqrtl (x);
+       }
+diff --git a/sysdeps/ieee754/ldbl-96/e_jnl.c b/sysdeps/ieee754/ldbl-96/e_jnl.c
+index 394921f564..2263b02203 100644
+--- a/sysdeps/ieee754/ldbl-96/e_jnl.c
++++ b/sysdeps/ieee754/ldbl-96/e_jnl.c
+@@ -142,6 +142,8 @@ __ieee754_jnl (int n, long double x)
+ 	      case 3:
+ 		temp = c - s;
+ 		break;
++	      default:
++	        temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	      }
+ 	    b = invsqrtpi * temp / sqrtl (x);
+ 	  }
+@@ -371,6 +373,8 @@ __ieee754_ynl (int n, long double x)
+ 	  case 3:
+ 	    temp = s + c;
+ 	    break;
++	  default:
++	    temp = 0; // just to prevent error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+ 	  }
+ 	b = invsqrtpi * temp / sqrtl (x);
+       }
+-- 
+2.17.1
+
diff --git a/meta/recipes-core/glibc/glibc/0032-soft-fp-ignore-maybe-uninitialized.patch b/meta/recipes-core/glibc/glibc/0032-soft-fp-ignore-maybe-uninitialized.patch
new file mode 100644
index 0000000000..4d56e55296
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/0032-soft-fp-ignore-maybe-uninitialized.patch
@@ -0,0 +1,72 @@
+From 0efa7fd1c800277d5323d05cb245c0536fe9ce22 Mon Sep 17 00:00:00 2001
+From: Martin Jansa <Martin.Jansa@gmail.com>
+Date: Sun, 16 Sep 2018 12:39:22 +0000
+Subject: [PATCH] soft-fp: ignore maybe-uninitialized
+
+* with -O it fails with:
+
+In file included from ../soft-fp/soft-fp.h:318,
+                 from ../sysdeps/ieee754/soft-fp/s_fdiv.c:28:
+../sysdeps/ieee754/soft-fp/s_fdiv.c: In function '__fdiv':
+../soft-fp/op-2.h:98:25: error: 'R_f1' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+        X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) \
+                         ^~
+../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f1' was declared here
+   FP_DECL_D (R);
+              ^
+../soft-fp/op-2.h:37:36: note: in definition of macro '_FP_FRAC_DECL_2'
+   _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
+                                    ^
+../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
+ # define FP_DECL_D(X)  _FP_DECL (2, X)
+                        ^~~~~~~~
+../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
+   FP_DECL_D (R);
+   ^~~~~~~~~
+../soft-fp/op-2.h:101:17: error: 'R_f0' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+       : (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0)); \
+                 ^~
+../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f0' was declared here
+   FP_DECL_D (R);
+              ^
+../soft-fp/op-2.h:37:14: note: in definition of macro '_FP_FRAC_DECL_2'
+   _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
+              ^
+../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
+ # define FP_DECL_D(X)  _FP_DECL (2, X)
+                        ^~~~~~~~
+../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
+   FP_DECL_D (R);
+   ^~~~~~~~~
+
+Upstream-Status: Submitted [https://www.sourceware.org/ml/libc-alpha/2018-09/msg00300.html]
+
+Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
+---
+ soft-fp/op-2.h | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/soft-fp/op-2.h b/soft-fp/op-2.h
+index 6020d663d4..6672337949 100644
+--- a/soft-fp/op-2.h
++++ b/soft-fp/op-2.h
+@@ -92,6 +92,8 @@
+ 	      X##_f1 = 0;						\
+ 	    }))
+ 
++#pragma GCC diagnostic push
++#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+ #define _FP_FRAC_SRS_2(X, N, sz)					\
+   (void) (((N) < _FP_W_TYPE_SIZE)					\
+ 	  ? ({								\
+@@ -109,6 +111,7 @@
+ 			    | X##_f0) != 0));				\
+ 	      X##_f1 = 0;						\
+ 	    }))
++#pragma GCC diagnostic pop
+ 
+ #define _FP_FRAC_ADDI_2(X, I)	\
+   __FP_FRAC_ADDI_2 (X##_f1, X##_f0, I)
+-- 
+2.17.1
+