VS: Fix mapping of `-Qspectre-` flag

The mapping for this flag was added by commit 43aa632f57 (VS: Populate
`-Qspectre-` flag table entry for v142, 2019-01-24, v3.14.0-rc1~74^2~7).
However, it did not do anything because the special logic added by
commit bb60ed6e72 (VS: Add flag table entry for -Qspectre, 2018-10-08,
v3.13.0-rc1~4^2) to move the `SpectreMitigation` element from
`ClCompile` to the top level only handled the presence of the setting
and not its value.  Extend the special logic to carry the value too.

Fixes: #19535

1 files changed, 7 insertions, 4 deletions

diff --git a/Source/cmVisualStudio10TargetGenerator.cxx b/Source/cmVisualStudio10TargetGenerator.cxx
index 8c6ba4e..7d25713 100644
--- a/Source/cmVisualStudio10TargetGenerator.cxx
+++ b/Source/cmVisualStudio10TargetGenerator.cxx
@@ -1229,8 +1229,11 @@ void cmVisualStudio10TargetGenerator::WriteMSToolConfigurationValues(
   if (this->IPOEnabledConfigurations.count(config) > 0) {
     e1.Element("WholeProgramOptimization", "true");
   }
-  if (this->SpectreMitigationConfigurations.count(config) > 0) {
-    e1.Element("SpectreMitigation", "Spectre");
+  {
+    auto s = this->SpectreMitigation.find(config);
+    if (s != this->SpectreMitigation.end()) {
+      e1.Element("SpectreMitigation", s->second);
+    }
   }
 }
 
@@ -2760,8 +2763,8 @@ bool cmVisualStudio10TargetGenerator::ComputeClOptions(
     }
   }
 
-  if (clOptions.HasFlag("SpectreMitigation")) {
-    this->SpectreMitigationConfigurations.insert(configName);
+  if (const char* s = clOptions.GetFlag("SpectreMitigation")) {
+    this->SpectreMitigation[configName] = s;
     clOptions.RemoveFlag("SpectreMitigation");
   }