From f9c768864a7784c518b6ac1af6515950c6eff6ec Mon Sep 17 00:00:00 2001
From: Christian Poveda <christianpoveda@protonmail.com>
Date: Mon, 14 Oct 2019 09:08:39 -0500
Subject: [PATCH] Use places instead of ptrs to write packed immtys

---
 src/helpers.rs          | 18 +++++++-----------
 src/shims/time.rs       | 12 ++++++------
 tests/run-pass/clock.rs |  1 +
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/helpers.rs b/src/helpers.rs
index 3012b1a955..9107958e01 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -318,27 +318,23 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
     // Writes several `ImmTy`s contiguosly into memory. This is useful when you have to pack
     // different values into a struct.
-    fn write_immediates(
+    fn write_packed_immediates(
         &mut self,
-        ptr: &Pointer<Tag>,
+        place: &MPlaceTy<'tcx, Tag>,
         imms: &[ImmTy<'tcx, Tag>],
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
         let tcx = &{ this.tcx.tcx };
 
-        let allocation = this.memory_mut().get_mut(ptr.alloc_id)?;
         let mut offset = Size::from_bytes(0);
 
-        for imm in imms {
-            let size = imm.layout.size;
-            allocation.write_scalar(
-                tcx,
-                ptr.offset(offset, tcx)?,
-                imm.to_scalar()?.into(),
-                size,
+        for &imm in imms {
+            this.write_immediate_to_mplace(
+                *imm,
+                place.offset(offset, None, imm.layout, tcx)?,
             )?;
-            offset += size;
+            offset += imm.layout.size;
         }
 
         Ok(())
diff --git a/src/shims/time.rs b/src/shims/time.rs
index 1b799b1330..0153c1a912 100644
--- a/src/shims/time.rs
+++ b/src/shims/time.rs
@@ -10,7 +10,7 @@ use crate::*;
 fn get_time<'tcx>() -> InterpResult<'tcx, Duration> {
     SystemTime::now()
         .duration_since(SystemTime::UNIX_EPOCH)
-        .map_err(|_| err_unsup_format!("Time went backwards").into())
+        .map_err(|_| err_unsup_format!("Times before the Unix epoch are not supported").into())
 }
 
 fn int_to_immty_checked<'tcx>(
@@ -52,7 +52,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             return Ok(-1);
         }
 
-        let tp = this.force_ptr(this.read_scalar(tp_op)?.not_undef()?)?;
+        let tp = this.deref_operand(tp_op)?;
 
         let duration = get_time()?;
         let tv_sec = duration.as_secs() as i128;
@@ -63,11 +63,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             int_to_immty_checked(tv_nsec, this.libc_ty_layout("c_long")?)?,
         ];
 
-        this.write_immediates(&tp, &imms)?;
+        this.write_packed_immediates(&tp, &imms)?;
 
         Ok(0)
     }
-    // Foreign function used by generic unix
+    // Foreign function used by generic unix (in particular macOS)
     fn gettimeofday(
         &mut self,
         tv_op: OpTy<'tcx, Tag>,
@@ -86,7 +86,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             return Ok(-1);
         }
 
-        let tv = this.force_ptr(this.read_scalar(tv_op)?.not_undef()?)?;
+        let tv = this.deref_operand(tv_op)?;
 
         let duration = get_time()?;
         let tv_sec = duration.as_secs() as i128;
@@ -97,7 +97,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             int_to_immty_checked(tv_usec, this.libc_ty_layout("suseconds_t")?)?,
         ];
 
-        this.write_immediates(&tv, &imms)?;
+        this.write_packed_immediates(&tv, &imms)?;
 
         Ok(0)
     }
diff --git a/tests/run-pass/clock.rs b/tests/run-pass/clock.rs
index 987a78fe1f..23f45f91ad 100644
--- a/tests/run-pass/clock.rs
+++ b/tests/run-pass/clock.rs
@@ -1,3 +1,4 @@
+// ignore-windows: TODO clock shims are not implemented on Windows
 // compile-flags: -Zmiri-disable-isolation
 
 use std::time::SystemTime;