From f8cc6a191723d763fc7a8908f3e5beb4eff8317f Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Thu, 2 Apr 2020 21:15:36 -0400
Subject: [PATCH] zig cc: fix ambiguity with -MT

In an MSVC context, `-MT` means
"Use static run-time"
and it is a flag with no parameter.

On POSIX it means
"Specify name of main file output in depfile"
and it is "joined or separate".

The former was interfering with the latter. Now, the MT flag is required
to be specified with a `/` to disambiguate: `/MT`.
---
 src-self-hosted/clang_options.zig      | 10 ++++
 src-self-hosted/clang_options_data.zig | 74 ++++++++++++++++++++------
 tools/update_clang_options.zig         | 37 ++++++++++++-
 3 files changed, 104 insertions(+), 17 deletions(-)

diff --git a/src-self-hosted/clang_options.zig b/src-self-hosted/clang_options.zig
index 70525655de..1b70c71dac 100644
--- a/src-self-hosted/clang_options.zig
+++ b/src-self-hosted/clang_options.zig
@@ -95,6 +95,16 @@ pub fn flagpd1(name: []const u8) CliArg {
     };
 }
 
+/// Shortcut function for initializing a `CliArg`
+pub fn flagpsl(name: []const u8) CliArg {
+    return .{
+        .name = name,
+        .syntax = .flag,
+        .zig_equivalent = .other,
+        .psl = true,
+    };
+}
+
 /// Shortcut function for initializing a `CliArg`
 pub fn joinpd1(name: []const u8) CliArg {
     return .{
diff --git a/src-self-hosted/clang_options_data.zig b/src-self-hosted/clang_options_data.zig
index 0b3a3b9416..2afe7f5681 100644
--- a/src-self-hosted/clang_options_data.zig
+++ b/src-self-hosted/clang_options_data.zig
@@ -34,10 +34,38 @@ flagpd1("M"),
     .pd2 = false,
     .psl = false,
 },
-flagpd1("MG"),
-flagpd1("MM"),
-flagpd1("MMD"),
-flagpd1("MP"),
+.{
+    .name = "MG",
+    .syntax = .flag,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "MM",
+    .syntax = .flag,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "MMD",
+    .syntax = .flag,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "MP",
+    .syntax = .flag,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
 .{
     .name = "MV",
     .syntax = .flag,
@@ -517,14 +545,7 @@ sepd1("Zlinker-input"),
     .pd2 = false,
     .psl = true,
 },
-.{
-    .name = "MT",
-    .syntax = .flag,
-    .zig_equivalent = .other,
-    .pd1 = true,
-    .pd2 = false,
-    .psl = true,
-},
+flagpsl("MT"),
 .{
     .name = "MTd",
     .syntax = .flag,
@@ -5463,9 +5484,30 @@ joinpd1("G="),
     .pd2 = false,
     .psl = false,
 },
-jspd1("MJ"),
-jspd1("MQ"),
-jspd1("MT"),
+.{
+    .name = "MJ",
+    .syntax = .joined_or_separate,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "MQ",
+    .syntax = .joined_or_separate,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "MT",
+    .syntax = .joined_or_separate,
+    .zig_equivalent = .dep_file,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
 .{
     .name = "AI",
     .syntax = .joined_or_separate,
@@ -5589,7 +5631,7 @@ jspd1("MT"),
 .{
     .name = "MP",
     .syntax = .joined,
-    .zig_equivalent = .other,
+    .zig_equivalent = .dep_file,
     .pd1 = true,
     .pd2 = false,
     .psl = true,
diff --git a/tools/update_clang_options.zig b/tools/update_clang_options.zig
index dd46f72d4c..fd6edbdf2c 100644
--- a/tools/update_clang_options.zig
+++ b/tools/update_clang_options.zig
@@ -206,6 +206,34 @@ const known_options = [_]KnownOpt{
         .name = "MF",
         .ident = "dep_file",
     },
+    .{
+        .name = "MT",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MG",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MJ",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MM",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MMD",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MP",
+        .ident = "dep_file",
+    },
+    .{
+        .name = "MQ",
+        .ident = "dep_file",
+    },
     .{
         .name = "F",
         .ident = "framework_dir",
@@ -336,7 +364,12 @@ pub fn main() anyerror!void {
         }
         const syntax = objSyntax(obj);
 
-        if (knownOption(name)) |ident| {
+        if (std.mem.eql(u8, name, "MT") and syntax == .flag) {
+            // `-MT foo` is ambiguous because there is also an -MT flag
+            // The canonical way to specify the flag is with `/MT` and so we make this
+            // the only way.
+            try stdout.print("flagpsl(\"{}\"),\n", .{name});
+        } else if (knownOption(name)) |ident| {
             try stdout.print(
                 \\.{{
                 \\    .name = "{}",
@@ -350,6 +383,8 @@ pub fn main() anyerror!void {
             , .{ name, syntax, ident, pd1, pd2, pslash });
         } else if (pd1 and !pd2 and !pslash and syntax == .flag) {
             try stdout.print("flagpd1(\"{}\"),\n", .{name});
+        } else if (!pd1 and !pd2 and pslash and syntax == .flag) {
+            try stdout.print("flagpsl(\"{}\"),\n", .{name});
         } else if (pd1 and !pd2 and !pslash and syntax == .joined) {
             try stdout.print("joinpd1(\"{}\"),\n", .{name});
         } else if (pd1 and !pd2 and !pslash and syntax == .joined_or_separate) {