From cb263e875e2ede820f4fab45a68d08ff6a9b2870 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Tue, 28 Jan 2014 14:59:28 -0500
Subject: [PATCH] enable fp-elim when debug info is disabled

This can almost be fully disabled, as it no longer breaks retrieving a
backtrace on OS X as verified by @alexcrichton. However, it still
breaks retrieving the values of parameters. This should be fixable in
the future via a proper location list...

Closes #7477
---
 src/librustc/back/link.rs                                   | 6 +++++-
 src/librustc/lib/llvm.rs                                    | 3 ++-
 src/rustllvm/PassWrapper.cpp                                | 5 +++--
 .../debug-info/function-prologue-stepping-no-split-stack.rs | 3 ---
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/librustc/back/link.rs b/src/librustc/back/link.rs
index 63c4d9f4a29..bd5494ba4cd 100644
--- a/src/librustc/back/link.rs
+++ b/src/librustc/back/link.rs
@@ -128,6 +128,9 @@ pub fn run_passes(sess: Session,
             };
             let use_softfp = sess.opts.debugging_opts & session::USE_SOFTFP != 0;
 
+            // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a parameter.
+            let no_fp_elim = sess.opts.debuginfo;
+
             let tm = sess.targ_cfg.target_strs.target_triple.with_c_str(|T| {
                 sess.opts.target_cpu.with_c_str(|CPU| {
                     sess.opts.target_feature.with_c_str(|Features| {
@@ -137,7 +140,8 @@ pub fn run_passes(sess: Session,
                             lib::llvm::RelocPIC,
                             OptLevel,
                             true,
-                            use_softfp
+                            use_softfp,
+                            no_fp_elim
                         )
                     })
                 })
diff --git a/src/librustc/lib/llvm.rs b/src/librustc/lib/llvm.rs
index 3693b00951b..3ed59c0195e 100644
--- a/src/librustc/lib/llvm.rs
+++ b/src/librustc/lib/llvm.rs
@@ -1728,7 +1728,8 @@ pub fn LLVMRustCreateTargetMachine(Triple: *c_char,
                                            Reloc: RelocMode,
                                            Level: CodeGenOptLevel,
                                            EnableSegstk: bool,
-                                           UseSoftFP: bool) -> TargetMachineRef;
+                                           UseSoftFP: bool,
+                                           NoFramePointerElim: bool) -> TargetMachineRef;
         pub fn LLVMRustDisposeTargetMachine(T: TargetMachineRef);
         pub fn LLVMRustAddAnalysisPasses(T: TargetMachineRef,
                                          PM: PassManagerRef,
diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index cab9c187eae..2bc96d9f0bf 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -68,7 +68,8 @@ LLVMRustCreateTargetMachine(const char *triple,
                             Reloc::Model RM,
                             CodeGenOpt::Level OptLevel,
                             bool EnableSegmentedStacks,
-                            bool UseSoftFloat) {
+                            bool UseSoftFloat,
+                            bool NoFramePointerElim) {
     std::string Error;
     Triple Trip(Triple::normalize(triple));
     const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Trip.getTriple(),
@@ -79,7 +80,7 @@ LLVMRustCreateTargetMachine(const char *triple,
     }
 
     TargetOptions Options;
-    Options.NoFramePointerElim = true;
+    Options.NoFramePointerElim = NoFramePointerElim;
     Options.EnableSegmentedStacks = EnableSegmentedStacks;
     Options.FloatABIType = FloatABI::Default;
     Options.UseSoftFloat = UseSoftFloat;
diff --git a/src/test/debug-info/function-prologue-stepping-no-split-stack.rs b/src/test/debug-info/function-prologue-stepping-no-split-stack.rs
index 4d940c91d2a..da2d4e09fc6 100644
--- a/src/test/debug-info/function-prologue-stepping-no-split-stack.rs
+++ b/src/test/debug-info/function-prologue-stepping-no-split-stack.rs
@@ -244,6 +244,3 @@ fn main() {
     while_expr(40, 41, 42);
     loop_expr(43, 44, 45);
 }
-
-
-
-- 
2.44.0