Fix #21045 - import __stdin causes compilation to pause while reading from stdin (#21047)

Moves the special handling of reading from stdin out of the semantic
routines to the DMD driver itself. All references to `__stdin.d` have
also been removed from the frontend implementation.

compiler/src/dmd/dmodule.d

@@ -58,12 +58,10 @@ import dmd.visitor;
 
 version (Windows)
 {
-    import core.sys.windows.winbase : getpid = GetCurrentProcessId;
     enum PathSeparator = '\\';
 }
 else version (Posix)
 {
-    import core.sys.posix.unistd : getpid;
     enum PathSeparator = '/';
 }
 else
@@ -577,12 +575,6 @@ extern (C++) final class Module : Package
         else
         {
             const(char)[] argdoc;
-            OutBuffer buf;
-            if (arg == "__stdin.d")
-            {
-                buf.printf("__stdin_%d.d", getpid());
-                arg = buf[];
-            }
             if (global.params.preservePaths)
                 argdoc = arg;
             else

compiler/src/dmd/file_manager.d

@@ -16,7 +16,6 @@ import dmd.root.stringtable : StringTable;
 import dmd.root.file : File, Buffer;
 import dmd.root.filename : FileName, isDirSeparator;
 import dmd.root.string : toDString;
-import dmd.errors;
 import dmd.globals;
 import dmd.identifier;
 import dmd.location;
@@ -184,9 +183,6 @@ nothrow:
         scope(exit) FileName.free(sdi.ptr);
 
         const sd = FileName.forceExt(filename, mars_ext);
-        // Special file name representing `stdin`, always assume its presence
-        if (sd == "__stdin.d")
-            return sd;
         if (checkLocal && FileName.exists(sd) == 1)
             return sd;
         scope(exit) FileName.free(sd.ptr);
@@ -312,20 +308,12 @@ nothrow:
         if (auto val = files.lookup(name))      // if `name` is cached
             return val.value;                   // return its contents
 
-        OutBuffer buf;
-        if (name == "__stdin.d")                // special name for reading from stdin
-        {
-            if (readFromStdin(buf))
-                fatal();
-        }
-        else
-        {
         if (FileName.exists(name) != 1) // if not an ordinary file
             return null;
 
+        OutBuffer buf;
         if (File.read(name, buf))
             return null;        // failed
-        }
 
         buf.write32(0);         // terminating dchar 0
 
@@ -351,36 +339,3 @@ nothrow:
         return val == null ? null : val.value;
     }
 }
-
-private bool readFromStdin(ref OutBuffer sink) nothrow
-{
-    import core.stdc.stdio;
-    import dmd.errors;
-
-    enum BufIncrement = 128 * 1024;
-
-    for (size_t j; 1; ++j)
-    {
-        char[] buffer = sink.allocate(BufIncrement);
-
-        // Fill up buffer
-        size_t filled = 0;
-        do
-        {
-            filled += fread(buffer.ptr + filled, 1, buffer.length - filled, stdin);
-            if (ferror(stdin))
-            {
-                import core.stdc.errno;
-                error(Loc.initial, "cannot read from stdin, errno = %d", errno);
-                return true;
-            }
-            if (feof(stdin)) // successful completion
-            {
-                sink.setsize(j * BufIncrement + filled);
-                return false;
-            }
-        } while (filled < BufIncrement);
-    }
-
-    assert(0);
-}

compiler/src/dmd/frontend.h

@@ -8412,6 +8412,7 @@ struct ImportPathInfo final
 struct Param final
 {
     bool obj;
+    bool readStdin;
     bool multiobj;
     bool trace;
     bool tracegc;
@@ -8499,6 +8500,7 @@ struct Param final
     bool parsingUnittestsRequired();
     Param() :
         obj(true),
+        readStdin(),
         multiobj(),
         trace(),
         tracegc(),
@@ -8577,8 +8579,9 @@ struct Param final
         timeTraceFile()
     {
     }
-    Param(bool obj, bool multiobj = false, bool trace = false, bool tracegc = false, bool vcg_ast = false, DiagnosticReporting useDeprecated = (DiagnosticReporting)1u, bool useUnitTests = false, bool useInline = false, bool release = false, bool preservePaths = false, DiagnosticReporting useWarnings = (DiagnosticReporting)2u, bool cov = false, uint8_t covPercent = 0u, bool ctfe_cov = false, bool ignoreUnsupportedPragmas = true, bool useModuleInfo = true, bool useTypeInfo = true, bool useExceptions = true, bool useGC = true, bool betterC = false, bool addMain = false, bool allInst = false, bool bitfields = false, CppStdRevision cplusplus = (CppStdRevision)201103u, Help help = Help(), Verbose v = Verbose(), FeatureState useDIP25 = (FeatureState)2u, FeatureState useDIP1000 = (FeatureState)0u, bool ehnogc = false, bool useDIP1021 = false, FeatureState fieldwise = (FeatureState)0u, bool fixAliasThis = false, FeatureState rvalueRefParam = (FeatureState)0u, FeatureState safer = (FeatureState)0u, FeatureState noSharedAccess = (FeatureState)0u, bool previewIn = false, bool inclusiveInContracts = false, bool shortenedMethods = true, bool fixImmutableConv = false, bool fix16997 = true, FeatureState dtorFields = (FeatureState)0u, FeatureState systemVariables = (FeatureState)0u, CHECKENABLE useInvariants = (CHECKENABLE)0u, CHECKENABLE useIn = (CHECKENABLE)0u, CHECKENABLE useOut = (CHECKENABLE)0u, CHECKENABLE useArrayBounds = (CHECKENABLE)0u, CHECKENABLE useAssert = (CHECKENABLE)0u, CHECKENABLE useSwitchError = (CHECKENABLE)0u, CHECKENABLE boundscheck = (CHECKENABLE)0u, CHECKACTION checkAction = (CHECKACTION)0u, CLIIdentifierTable dIdentifierTable = (CLIIdentifierTable)0u, CLIIdentifierTable cIdentifierTable = (CLIIdentifierTable)0u, _d_dynamicArray< const char > argv0 = {}, Array<const char* > modFileAliasStrings = Array<const char* >(), Array<ImportPathInfo > imppath = Array<ImportPathInfo >(), Array<const char* > fileImppath = Array<const char* >(), _d_dynamicArray< const char > objdir = {}, _d_dynamicArray< const char > objname = {}, _d_dynamicArray< const char > libname = {}, Output ddoc = Output(), Output dihdr = Output(), Output cxxhdr = Output(), Output json = Output(), JsonFieldFlags jsonFieldFlags = (JsonFieldFlags)0u, Output makeDeps = Output(), Output mixinOut = Output(), Output moduleDeps = Output(), bool debugEnabled = false, bool run = false, Array<const char* > runargs = Array<const char* >(), Array<const char* > cppswitches = Array<const char* >(), const char* cpp = nullptr, Array<const char* > objfiles = Array<const char* >(), Array<const char* > linkswitches = Array<const char* >(), Array<bool > linkswitchIsForCC = Array<bool >(), Array<const char* > libfiles = Array<const char* >(), Array<const char* > dllfiles = Array<const char* >(), _d_dynamicArray< const char > deffile = {}, _d_dynamicArray< const char > resfile = {}, _d_dynamicArray< const char > exefile = {}, _d_dynamicArray< const char > mapfile = {}, bool fullyQualifiedObjectFiles = false, bool timeTrace = false, uint32_t timeTraceGranularityUs = 500u, const char* timeTraceFile = nullptr) :
+    Param(bool obj, bool readStdin = false, bool multiobj = false, bool trace = false, bool tracegc = false, bool vcg_ast = false, DiagnosticReporting useDeprecated = (DiagnosticReporting)1u, bool useUnitTests = false, bool useInline = false, bool release = false, bool preservePaths = false, DiagnosticReporting useWarnings = (DiagnosticReporting)2u, bool cov = false, uint8_t covPercent = 0u, bool ctfe_cov = false, bool ignoreUnsupportedPragmas = true, bool useModuleInfo = true, bool useTypeInfo = true, bool useExceptions = true, bool useGC = true, bool betterC = false, bool addMain = false, bool allInst = false, bool bitfields = false, CppStdRevision cplusplus = (CppStdRevision)201103u, Help help = Help(), Verbose v = Verbose(), FeatureState useDIP25 = (FeatureState)2u, FeatureState useDIP1000 = (FeatureState)0u, bool ehnogc = false, bool useDIP1021 = false, FeatureState fieldwise = (FeatureState)0u, bool fixAliasThis = false, FeatureState rvalueRefParam = (FeatureState)0u, FeatureState safer = (FeatureState)0u, FeatureState noSharedAccess = (FeatureState)0u, bool previewIn = false, bool inclusiveInContracts = false, bool shortenedMethods = true, bool fixImmutableConv = false, bool fix16997 = true, FeatureState dtorFields = (FeatureState)0u, FeatureState systemVariables = (FeatureState)0u, CHECKENABLE useInvariants = (CHECKENABLE)0u, CHECKENABLE useIn = (CHECKENABLE)0u, CHECKENABLE useOut = (CHECKENABLE)0u, CHECKENABLE useArrayBounds = (CHECKENABLE)0u, CHECKENABLE useAssert = (CHECKENABLE)0u, CHECKENABLE useSwitchError = (CHECKENABLE)0u, CHECKENABLE boundscheck = (CHECKENABLE)0u, CHECKACTION checkAction = (CHECKACTION)0u, CLIIdentifierTable dIdentifierTable = (CLIIdentifierTable)0u, CLIIdentifierTable cIdentifierTable = (CLIIdentifierTable)0u, _d_dynamicArray< const char > argv0 = {}, Array<const char* > modFileAliasStrings = Array<const char* >(), Array<ImportPathInfo > imppath = Array<ImportPathInfo >(), Array<const char* > fileImppath = Array<const char* >(), _d_dynamicArray< const char > objdir = {}, _d_dynamicArray< const char > objname = {}, _d_dynamicArray< const char > libname = {}, Output ddoc = Output(), Output dihdr = Output(), Output cxxhdr = Output(), Output json = Output(), JsonFieldFlags jsonFieldFlags = (JsonFieldFlags)0u, Output makeDeps = Output(), Output mixinOut = Output(), Output moduleDeps = Output(), bool debugEnabled = false, bool run = false, Array<const char* > runargs = Array<const char* >(), Array<const char* > cppswitches = Array<const char* >(), const char* cpp = nullptr, Array<const char* > objfiles = Array<const char* >(), Array<const char* > linkswitches = Array<const char* >(), Array<bool > linkswitchIsForCC = Array<bool >(), Array<const char* > libfiles = Array<const char* >(), Array<const char* > dllfiles = Array<const char* >(), _d_dynamicArray< const char > deffile = {}, _d_dynamicArray< const char > resfile = {}, _d_dynamicArray< const char > exefile = {}, _d_dynamicArray< const char > mapfile = {}, bool fullyQualifiedObjectFiles = false, bool timeTrace = false, uint32_t timeTraceGranularityUs = 500u, const char* timeTraceFile = nullptr) :
         obj(obj),
+        readStdin(readStdin),
         multiobj(multiobj),
         trace(trace),
         tracegc(tracegc),

compiler/src/dmd/globals.d

@@ -160,6 +160,7 @@ extern (C++) struct ImportPathInfo {
 extern (C++) struct Param
 {
     bool obj = true;        // write object file
+    bool readStdin;         // saw "-" on command line, read source file from stdin
     bool multiobj;          // break one object file into multiple ones
     bool trace;             // insert profiling hooks
     bool tracegc;           // instrument calls to 'new'

compiler/src/dmd/globals.h

@@ -168,6 +168,7 @@ struct ImportPathInfo
 struct Param
 {
     d_bool obj;           // write object file
+    d_bool readStdin;     // read source file from stdin
     d_bool multiobj;      // break one object file into multiple ones
     d_bool trace;         // insert profiling hooks
     d_bool tracegc;       // instrument calls to 'new'

compiler/src/dmd/main.d

@@ -353,7 +353,7 @@ private int tryMain(size_t argc, const(char)** argv, ref Param params)
     {
         fatal();
     }
-    if (files.length == 0)
+    if (files.length == 0 && !params.readStdin)
     {
         if (params.jsonFieldFlags)
         {

compiler/src/dmd/mars.d

@@ -59,6 +59,13 @@ import dmd.semantic3;
 import dmd.target;
 import dmd.utils;
 
+version (Windows)
+    import core.sys.windows.winbase : getpid = GetCurrentProcessId;
+else version (Posix)
+    import core.sys.posix.unistd : getpid;
+else
+    static assert(0);
+
 /**
  * Print DMD's logo on stdout
  */
@@ -1734,7 +1741,7 @@ bool parseCommandLine(const ref Strings arguments, const size_t argc, ref Param
                     break;
                 }
                 if (runarg == "-")
-                    files.push("__stdin.d");
+                    params.readStdin = true;
                 else
                     files.push(arguments[i + 1]);
                 params.runargs.setDim(length - 1);
@@ -1751,7 +1758,7 @@ bool parseCommandLine(const ref Strings arguments, const size_t argc, ref Param
             }
         }
         else if (p[1] == '\0')
-            files.push("__stdin.d");
+            params.readStdin = true;
         else
         {
         Lerror:
@@ -1937,10 +1944,38 @@ bool createModules(ref Strings files, ref Strings libmodules, ref Param params,
         modules.push(m);
         if (firstmodule)
         {
-            global.params.objfiles.push(m.objfile.toChars());
+            params.objfiles.push(m.objfile.toChars());
             firstmodule = false;
         }
     }
+
+    // Special module representing `stdin`
+    if (params.readStdin)
+    {
+        Module m;
+        if (createModule("__stdin.d", libmodules, params, target, eSink, m))
+            return true;
+        if (m is null)
+            return false;
+
+        modules.push(m);
+
+        // Set the source file contents of the module
+        OutBuffer buf;
+        buf.readFromStdin();
+        m.src = cast(ubyte[])buf.extractSlice();
+
+        // Give unique outfile name
+        OutBuffer namebuf;
+        namebuf.printf("__stdin_%d", getpid());
+
+        auto filename = FileName.forceExt(namebuf.extractSlice(), target.obj_ext);
+        m.objfile = FileName(filename);
+
+        if (firstmodule)
+            params.objfiles.push(m.objfile.toChars());
+    }
+
     return false;
 }
 
@@ -1959,3 +1994,37 @@ Module moduleWithEmptyMain()
     result.semantic3(null);
     return result;
 }
+
+private void readFromStdin(ref OutBuffer sink) nothrow
+{
+    import core.stdc.stdio;
+    import dmd.errors;
+
+    enum BufIncrement = 128 * 1024;
+
+    for (size_t j; 1; ++j)
+    {
+        char[] buffer = sink.allocate(BufIncrement + 16);
+
+        // Fill up buffer
+        size_t filled = 0;
+        do
+        {
+            filled += fread(buffer.ptr + filled, 1, buffer.length - filled, stdin);
+            if (ferror(stdin))
+            {
+                import core.stdc.errno;
+                error(Loc.initial, "cannot read from stdin, errno = %d", errno);
+                fatal();
+            }
+            if (feof(stdin)) // successful completion
+            {
+                memset(buffer.ptr + filled, '\0', 16);
+                sink.setsize(j * BufIncrement + filled);
+                return;
+            }
+        } while (filled < BufIncrement);
+    }
+
+    assert(0);
+}

compiler/test/fail_compilation/fail21045.d

@@ -0,0 +1,12 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fail21045.d(12): Error: unable to read module `__stdin`
+fail_compilation/fail21045.d(12):        Expected '__stdin.d' or '__stdin/package.d' in one of the following import paths:
+import path[0] = fail_compilation
+import path[1] = $p:druntime/import$
+import path[2] = $p:phobos$
+---
+*/
+
+import __stdin;