Auto merge of #1276 - RalfJung:scalar-precise-sizes, r=RalfJung

Construct Scalar with precise sizes

Author: bors

src/eval.rs

@@ -6,7 +6,7 @@ use std::convert::TryFrom;
 use rand::rngs::StdRng;
 use rand::SeedableRng;
 
-use rustc::ty::layout::{LayoutOf, Size};
+use rustc::ty::layout::LayoutOf;
 use rustc::ty::{self, TyCtxt};
 use rustc_hir::def_id::DefId;
 
@@ -96,7 +96,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
     // First argument: pointer to `main()`.
     let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance));
     // Second argument (argc): length of `config.args`.
-    let argc = Scalar::from_uint(u64::try_from(config.args.len()).unwrap(), ecx.pointer_size());
+    let argc = Scalar::from_machine_usize(u64::try_from(config.args.len()).unwrap(), &ecx);
     // Third argument (`argv`): created from `config.args`.
     let argv = {
         // Put each argument in memory, collect pointers.
@@ -152,10 +152,9 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
             let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into());
             ecx.machine.cmd_line = Some(cmd_place.ptr);
             // Store the UTF-16 string. We just allocated so we know the bounds are fine.
-            let char_size = Size::from_bytes(2);
             for (idx, &c) in cmd_utf16.iter().enumerate() {
                 let place = ecx.mplace_field(cmd_place, idx)?;
-                ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
+                ecx.write_scalar(Scalar::from_u16(c), place.into())?;
             }
         }
         argv

src/helpers.rs

@@ -92,7 +92,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     /// Test if this immediate equals 0.
     fn is_null(&self, val: Scalar<Tag>) -> InterpResult<'tcx, bool> {
         let this = self.eval_context_ref();
-        let null = Scalar::from_int(0, this.memory.pointer_size());
+        let null = Scalar::ptr_null(this);
         this.ptr_eq(val, null)
     }
 

src/machine.rs

@@ -130,7 +130,7 @@ impl MemoryExtra {
                 // This should be all-zero, pointer-sized.
                 let layout = this.layout_of(this.tcx.types.usize)?;
                 let place = this.allocate(layout, MiriMemoryKind::Machine.into());
-                this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
+                this.write_scalar(Scalar::from_machine_usize(0, this), place.into())?;
                 Self::add_extern_static(this, "__cxa_thread_atexit_impl", place.ptr);
                 // "environ"
                 Self::add_extern_static(this, "environ", this.machine.env_vars.environ.unwrap().ptr);
@@ -316,10 +316,10 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
         let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
         // First argument: `size`.
         // (`0` is allowed here -- this is expected to be handled by the lang item).
-        let size = Scalar::from_uint(layout.size.bytes(), ecx.pointer_size());
+        let size = Scalar::from_machine_usize(layout.size.bytes(), ecx);
 
         // Second argument: `align`.
-        let align = Scalar::from_uint(layout.align.abi.bytes(), ecx.pointer_size());
+        let align = Scalar::from_machine_usize(layout.align.abi.bytes(), ecx);
 
         // Call the `exchange_malloc` lang item.
         let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();

src/shims/env.rs

@@ -108,7 +108,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         name_op: OpTy<'tcx, Tag>, // LPCWSTR
         buf_op: OpTy<'tcx, Tag>,  // LPWSTR
         size_op: OpTy<'tcx, Tag>, // DWORD
-    ) -> InterpResult<'tcx, u64> {
+    ) -> InterpResult<'tcx, u32> {
         let this = self.eval_context_mut();
         this.assert_target_os("windows", "GetEnvironmentVariableW");
 
@@ -124,17 +124,17 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
                 let buf_ptr = this.read_scalar(buf_op)?.not_undef()?;
                 // `buf_size` represents the size in characters.
-                let buf_size = u64::try_from(this.read_scalar(size_op)?.to_u32()?).unwrap();
+                let buf_size = u64::from(this.read_scalar(size_op)?.to_u32()?);
                 let (success, len) = this.write_os_str_to_wide_str(&var, buf_ptr, buf_size)?;
 
                 if success {
                     // If the function succeeds, the return value is the number of characters stored in the buffer pointed to by lpBuffer,
                     // not including the terminating null character.
-                    len
+                    u32::try_from(len).unwrap()
                 } else {
                     // If lpBuffer is not large enough to hold the data, the return value is the buffer size, in characters,
                     // required to hold the string and its terminating null character and the contents of lpBuffer are undefined.
-                    len + 1
+                    u32::try_from(len).unwrap().checked_add(1).unwrap()
                 }
             }
             None => {
@@ -337,14 +337,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             // This is memory backing an extern static, hence `Machine`, not `Env`.
             let layout = this.layout_of(this.tcx.types.usize)?;
             let place = this.allocate(layout, MiriMemoryKind::Machine.into());
-            this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
             this.machine.env_vars.environ = Some(place);
         }
 
         // Collect all the pointers to each variable in a vector.
         let mut vars: Vec<Scalar<Tag>> = this.machine.env_vars.map.values().map(|&ptr| ptr.into()).collect();
         // Add the trailing null pointer.
-        vars.push(Scalar::from_int(0, this.pointer_size()));
+        vars.push(Scalar::ptr_null(this));
         // Make an array with all these pointers inside Miri.
         let tcx = this.tcx;
         let vars_layout =

src/shims/foreign_items.rs

@@ -47,7 +47,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn malloc(&mut self, size: u64, zero_init: bool, kind: MiriMemoryKind) -> Scalar<Tag> {
         let this = self.eval_context_mut();
         if size == 0 {
-            Scalar::from_int(0, this.pointer_size())
+            Scalar::ptr_null(this)
         } else {
             let align = this.min_align(size, kind);
             let ptr = this.memory.allocate(Size::from_bytes(size), align, kind.into());
@@ -78,7 +78,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let new_align = this.min_align(new_size, kind);
         if this.is_null(old_ptr)? {
             if new_size == 0 {
-                Ok(Scalar::from_int(0, this.pointer_size()))
+                Ok(Scalar::ptr_null(this))
             } else {
                 let new_ptr =
                     this.memory.allocate(Size::from_bytes(new_size), new_align, kind.into());
@@ -88,7 +88,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             let old_ptr = this.force_ptr(old_ptr)?;
             if new_size == 0 {
                 this.memory.deallocate(old_ptr, None, kind.into())?;
-                Ok(Scalar::from_int(0, this.pointer_size()))
+                Ok(Scalar::ptr_null(this))
             } else {
                 let new_ptr = this.memory.reallocate(
                     old_ptr,
@@ -296,7 +296,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     }
                 };
 
-                this.write_scalar(Scalar::from_int(result, Size::from_bits(32)), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "memrchr" => {
                 let ptr = this.read_scalar(args[0])?.not_undef()?;
@@ -334,7 +334,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             "strlen" => {
                 let ptr = this.read_scalar(args[0])?.not_undef()?;
                 let n = this.memory.read_c_str(ptr)?.len();
-                this.write_scalar(Scalar::from_uint(u64::try_from(n).unwrap(), dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_machine_usize(u64::try_from(n).unwrap(), this), dest)?;
             }
 
             // math functions

src/shims/foreign_items/posix.rs

@@ -26,33 +26,33 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
             "unsetenv" => {
                 let result = this.unsetenv(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "setenv" => {
                 let result = this.setenv(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "getcwd" => {
                 let result = this.getcwd(args[0], args[1])?;
                 this.write_scalar(result, dest)?;
             }
             "chdir" => {
                 let result = this.chdir(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
 
             // File related shims
             "open" | "open64" => {
                 let result = this.open(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "fcntl" => {
                 let result = this.fcntl(args[0], args[1], args.get(2).cloned())?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "read" => {
                 let result = this.read(args[0], args[1], args[2])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
             }
             "write" => {
                 let fd = this.read_scalar(args[0])?.to_i32()?;
@@ -85,35 +85,36 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     this.write(args[0], args[1], args[2])?
                 };
                 // Now, `result` is the value we return back to the program.
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
             }
             "unlink" => {
                 let result = this.unlink(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "symlink" => {
                 let result = this.symlink(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "rename" => {
                 let result = this.rename(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "mkdir" => {
                 let result = this.mkdir(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "rmdir" => {
                 let result = this.rmdir(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "closedir" => {
                 let result = this.closedir(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "lseek" | "lseek64" => {
                 let result = this.lseek64(args[0], args[1], args[2])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                // "lseek" is only used on macOS which is 64bit-only, so `i64` always works.
+                this.write_scalar(Scalar::from_i64(result), dest)?;
             }
 
             // Allocation
@@ -165,8 +166,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let name = this.read_scalar(args[0])?.to_i32()?;
 
                 let sysconfs = &[
-                    ("_SC_PAGESIZE", Scalar::from_int(PAGE_SIZE, dest.layout.size)),
-                    ("_SC_NPROCESSORS_ONLN", Scalar::from_int(NUM_CPUS, dest.layout.size)),
+                    ("_SC_PAGESIZE", Scalar::from_int(PAGE_SIZE, this.pointer_size())),
+                    ("_SC_NPROCESSORS_ONLN", Scalar::from_int(NUM_CPUS, this.pointer_size())),
                 ];
                 let mut result = None;
                 for &(sysconf_name, value) in sysconfs {

src/shims/foreign_items/posix/linux.rs

@@ -24,15 +24,15 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             // in the `posix` module.
             "close" => {
                 let result = this.close(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "opendir" => {
                 let result = this.opendir(args[0])?;
                 this.write_scalar(result, dest)?;
             }
             "readdir64_r" => {
                 let result = this.linux_readdir64_r(args[0], args[1], args[2])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             // Linux-only
             "posix_fadvise" => {
@@ -48,7 +48,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             "clock_gettime" => {
                 // This is a POSIX function but it has only been tested on linux.
                 let result = this.clock_gettime(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
 
             // Querying system information
@@ -59,11 +59,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let size_place = this.deref_operand(args[2])?;
 
                 this.write_scalar(
-                    Scalar::from_uint(STACK_ADDR, addr_place.layout.size),
+                    Scalar::from_uint(STACK_ADDR, this.pointer_size()),
                     addr_place.into(),
                 )?;
                 this.write_scalar(
-                    Scalar::from_uint(STACK_SIZE, size_place.layout.size),
+                    Scalar::from_uint(STACK_SIZE, this.pointer_size()),
                     size_place.into(),
                 )?;
 
@@ -93,7 +93,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     id if id == sys_statx => {
                         // The first argument is the syscall id, so skip over it.
                         let result = this.linux_statx(args[1], args[2], args[3], args[4], args[5])?;
-                        this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                        this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
                     }
                     id => throw_unsup_format!("miri does not support syscall ID {}", id),
                 }
@@ -110,7 +110,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
                 let einval = this.eval_libc("EINVAL")?;
                 this.set_last_error(einval)?;
-                this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(-1), dest)?;
             }
 
             // Incomplete shims that we "stub out" just to get pre-main initialziation code to work.
@@ -140,6 +140,6 @@ fn getrandom<'tcx>(
     let _flags = this.read_scalar(args[2])?.to_i32()?;
 
     this.gen_random(ptr, len)?;
-    this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
+    this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;
     Ok(())
 }

src/shims/foreign_items/posix/macos.rs

@@ -22,27 +22,27 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             // File related shims
             "close$NOCANCEL" => {
                 let result = this.close(args[0])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "stat$INODE64" => {
                 let result = this.macos_stat(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "lstat$INODE64" => {
                 let result = this.macos_lstat(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "fstat$INODE64" => {
                 let result = this.macos_fstat(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "opendir$INODE64" => {
                 let result = this.opendir(args[0])?;
                 this.write_scalar(result, dest)?;
             }
             "readdir_r$INODE64" => {
                 let result = this.macos_readdir_r(args[0], args[1], args[2])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
 
             // Environment related shims
@@ -53,11 +53,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             // Time related shims
             "gettimeofday" => {
                 let result = this.gettimeofday(args[0], args[1])?;
-                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
             }
             "mach_absolute_time" => {
                 let result = this.mach_absolute_time()?;
-                this.write_scalar(Scalar::from_uint(result, dest.layout.size), dest)?;
+                this.write_scalar(Scalar::from_u64(result), dest)?;
             }
 
             // Access to command-line arguments
@@ -79,12 +79,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             // Querying system information
             "pthread_get_stackaddr_np" => {
                 let _thread = this.read_scalar(args[0])?.not_undef()?;
-                let stack_addr = Scalar::from_uint(STACK_ADDR, dest.layout.size);
+                let stack_addr = Scalar::from_uint(STACK_ADDR, this.pointer_size());
                 this.write_scalar(stack_addr, dest)?;
             }
             "pthread_get_stacksize_np" => {
                 let _thread = this.read_scalar(args[0])?.not_undef()?;
-                let stack_size = Scalar::from_uint(STACK_SIZE, dest.layout.size);
+                let stack_size = Scalar::from_uint(STACK_SIZE, this.pointer_size());
                 this.write_scalar(stack_size, dest)?;
             }